/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2007-2008 Kristian Duske
Copyright (C) 2010-2014 QuakeSpasm developers

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// gl_vidsdl.c -- SDL GL vid component

#include "quakedef.hpp"
#include "cfgfile.hpp"
#include "bgmusic.hpp"
#include "resource.hpp"
#if defined(SDL_FRAMEWORK) || defined(NO_SDL_CONFIG)
#if defined(USE_SDL2)
#include <SDL2/SDL.h>
#else
#include <SDL/SDL.h>
#endif
#else
#include "SDL.h"
#endif

//ericw -- for putting the driver into multithreaded mode
#ifdef __APPLE__
#include <OpenGL/OpenGL.h>
#endif

#define MAX_MODE_LIST	600 //johnfitz -- was 30
#define MAX_BPPS_LIST	5
#define MAX_RATES_LIST	20
#define WARP_WIDTH		320
#define WARP_HEIGHT		200
#define MAXWIDTH		10000
#define MAXHEIGHT		10000

#define DEFAULT_SDL_FLAGS	SDL_OPENGL

#define DEFAULT_REFRESHRATE	60

typedef struct {
    int width;
    int height;
    int refreshrate;
    int bpp;
} vmode_t;

static const char *gl_vendor;
static const char *gl_renderer;
static const char *gl_version;
static int gl_version_major;
static int gl_version_minor;
static const char *gl_extensions;
static char *gl_extensions_nice;

static vmode_t modelist[MAX_MODE_LIST];
static int nummodes;

static bool vid_initialized = false;

#if defined(USE_SDL2)
static SDL_Window *draw_context;
static SDL_GLContext gl_context;
#else
static SDL_Surface *draw_context;
#endif

static bool vid_locked = false; //johnfitz
static bool vid_changed = false;

static void VID_Menu_Init(void); //johnfitz
static void VID_Menu_f(void); //johnfitz
static void VID_MenuDraw(void);

static void VID_MenuKey(int key);

static void ClearAllStates(void);

static void GL_Init(void);

static void GL_SetupState(void); //johnfitz

viddef_t vid; // global video state
modestate_t modestate = MS_UNINIT;
bool scr_skipupdate;

bool gl_mtexable = false;
bool gl_packed_pixels = false;
bool gl_texture_env_combine = false; //johnfitz
bool gl_texture_env_add = false; //johnfitz
bool gl_swap_control = false; //johnfitz
bool gl_anisotropy_able = false; //johnfitz
float gl_max_anisotropy; //johnfitz
bool gl_texture_NPOT = false; //ericw
bool gl_vbo_able = false; //ericw
bool gl_glsl_able = false; //ericw
GLint gl_max_texture_units = 0; //ericw
bool gl_glsl_gamma_able = false; //ericw
bool gl_glsl_alias_able = false; //ericw
int gl_stencilbits;

PFNGLMULTITEXCOORD2FARBPROC GL_MTexCoord2fFunc = NULL; //johnfitz
PFNGLACTIVETEXTUREARBPROC GL_SelectTextureFunc = NULL; //johnfitz
PFNGLCLIENTACTIVETEXTUREARBPROC GL_ClientActiveTextureFunc = NULL; //ericw
PFNGLBINDBUFFERARBPROC GL_BindBufferFunc = NULL; //ericw
PFNGLBUFFERDATAARBPROC GL_BufferDataFunc = NULL; //ericw
PFNGLBUFFERSUBDATAARBPROC GL_BufferSubDataFunc = NULL; //ericw
PFNGLDELETEBUFFERSARBPROC GL_DeleteBuffersFunc = NULL; //ericw
PFNGLGENBUFFERSARBPROC GL_GenBuffersFunc = NULL; //ericw

QS_PFNGLCREATESHADERPROC GL_CreateShaderFunc = NULL; //ericw
QS_PFNGLDELETESHADERPROC GL_DeleteShaderFunc = NULL; //ericw
QS_PFNGLDELETEPROGRAMPROC GL_DeleteProgramFunc = NULL; //ericw
QS_PFNGLSHADERSOURCEPROC GL_ShaderSourceFunc = NULL; //ericw
QS_PFNGLCOMPILESHADERPROC GL_CompileShaderFunc = NULL; //ericw
QS_PFNGLGETSHADERIVPROC GL_GetShaderivFunc = NULL; //ericw
QS_PFNGLGETSHADERINFOLOGPROC GL_GetShaderInfoLogFunc = NULL; //ericw
QS_PFNGLGETPROGRAMIVPROC GL_GetProgramivFunc = NULL; //ericw
QS_PFNGLGETPROGRAMINFOLOGPROC GL_GetProgramInfoLogFunc = NULL; //ericw
QS_PFNGLCREATEPROGRAMPROC GL_CreateProgramFunc = NULL; //ericw
QS_PFNGLATTACHSHADERPROC GL_AttachShaderFunc = NULL; //ericw
QS_PFNGLLINKPROGRAMPROC GL_LinkProgramFunc = NULL; //ericw
QS_PFNGLBINDATTRIBLOCATIONFUNC GL_BindAttribLocationFunc = NULL; //ericw
QS_PFNGLUSEPROGRAMPROC GL_UseProgramFunc = NULL; //ericw
QS_PFNGLGETATTRIBLOCATIONPROC GL_GetAttribLocationFunc = NULL; //ericw
QS_PFNGLVERTEXATTRIBPOINTERPROC GL_VertexAttribPointerFunc = NULL; //ericw
QS_PFNGLENABLEVERTEXATTRIBARRAYPROC GL_EnableVertexAttribArrayFunc = NULL; //ericw
QS_PFNGLDISABLEVERTEXATTRIBARRAYPROC GL_DisableVertexAttribArrayFunc = NULL; //ericw
QS_PFNGLGETUNIFORMLOCATIONPROC GL_GetUniformLocationFunc = NULL; //ericw
QS_PFNGLUNIFORM1IPROC GL_Uniform1iFunc = NULL; //ericw
QS_PFNGLUNIFORM1FPROC GL_Uniform1fFunc = NULL; //ericw
QS_PFNGLUNIFORM3FPROC GL_Uniform3fFunc = NULL; //ericw
QS_PFNGLUNIFORM4FPROC GL_Uniform4fFunc = NULL; //ericw

QS_PFNGENERATEMIPMAP GL_GenerateMipmap = NULL;

//====================================

//johnfitz -- new cvars
static convar vid_fullscreen{"vid_fullscreen", "0", {.archive = true}}; // QuakeSpasm, was "1"
static convar vid_width{"vid_width", "800", {.archive = true}}; // QuakeSpasm, was 640
static convar vid_height{"vid_height", "600", {.archive = true}}; // QuakeSpasm, was 480
static convar vid_bpp{"vid_bpp", "16", {.archive = true}};
static convar vid_refreshrate{"vid_refreshrate", "60", {.archive = true}};
static convar vid_vsync{"vid_vsync", "0", {.archive = true}};
static convar vid_fsaa{"vid_fsaa", "0", {.archive = true}}; // QuakeSpasm
static convar vid_desktopfullscreen{"vid_desktopfullscreen", "0", {.archive = true}}; // QuakeSpasm
static convar vid_borderless{"vid_borderless", "0", {.archive = true}}; // QuakeSpasm
//johnfitz

convar vid_gamma = {"gamma", "1", {.archive = true}}; //johnfitz -- moved here from view.c
convar vid_contrast = {"contrast", "1", {.archive = true}}; //QuakeSpasm, MarkV

//==========================================================================
//
//  HARDWARE GAMMA -- johnfitz
//
//==========================================================================

#define	USE_GAMMA_RAMPS			0

#if USE_GAMMA_RAMPS
static unsigned short vid_gamma_red[256];
static unsigned short vid_gamma_green[256];
static unsigned short vid_gamma_blue[256];

static unsigned short vid_sysgamma_red[256];
static unsigned short vid_sysgamma_green[256];
static unsigned short vid_sysgamma_blue[256];
#endif

static bool gammaworks = false; // whether hw-gamma works
static int fsaa;

/*
================
VID_Gamma_SetGamma -- apply gamma correction
================
*/
static void VID_Gamma_SetGamma(void) {
    if (gl_glsl_gamma_able)
        return;

    if (draw_context && gammaworks) {
        float value;

        if (vid_gamma.value > (1.0f / GAMMA_MAX))
            value = 1.0f / vid_gamma.value;
        else
            value = GAMMA_MAX;

#if defined(USE_SDL2)
# if USE_GAMMA_RAMPS
        if (SDL_SetWindowGammaRamp(draw_context, vid_gamma_red, vid_gamma_green, vid_gamma_blue) != 0)
            console::info("VID_Gamma_SetGamma: failed on SDL_SetWindowGammaRamp\n");
# else
        if (SDL_SetWindowBrightness(draw_context, value) != 0)
            console::info("VID_Gamma_SetGamma: failed on SDL_SetWindowBrightness\n");
# endif
#else /* USE_SDL2 */
# if USE_GAMMA_RAMPS
        if (SDL_SetGammaRamp(vid_gamma_red, vid_gamma_green, vid_gamma_blue) == -1)
            console::info("VID_Gamma_SetGamma: failed on SDL_SetGammaRamp\n");
# else
        if (SDL_SetGamma(value, value, value) == -1)
            console::info("VID_Gamma_SetGamma: failed on SDL_SetGamma\n");
# endif
#endif /* USE_SDL2 */
    }
}

/*
================
VID_Gamma_Restore -- restore system gamma
================
*/
static void VID_Gamma_Restore(void) {
    if (gl_glsl_gamma_able)
        return;

    if (draw_context && gammaworks) {
#if defined(USE_SDL2)
# if USE_GAMMA_RAMPS
        if (SDL_SetWindowGammaRamp(draw_context, vid_sysgamma_red, vid_sysgamma_green, vid_sysgamma_blue) != 0)
            console::info("VID_Gamma_Restore: failed on SDL_SetWindowGammaRamp\n");
# else
        if (SDL_SetWindowBrightness(draw_context, 1) != 0)
            console::info("VID_Gamma_Restore: failed on SDL_SetWindowBrightness\n");
# endif
#else /* USE_SDL2 */
# if USE_GAMMA_RAMPS
        if (SDL_SetGammaRamp(vid_sysgamma_red, vid_sysgamma_green, vid_sysgamma_blue) == -1)
            console::info("VID_Gamma_Restore: failed on SDL_SetGammaRamp\n");
# else
        if (SDL_SetGamma(1, 1, 1) == -1)
            console::info("VID_Gamma_Restore: failed on SDL_SetGamma\n");
# endif
#endif /* USE_SDL2 */
    }
}

/*
================
VID_Gamma_Shutdown -- called on exit
================
*/
static void VID_Gamma_Shutdown(void) {
    VID_Gamma_Restore();
}

/*
================
VID_Gamma_f -- callback when the cvar changes
================
*/
static void VID_Gamma_f(convar *var) {
    if (gl_glsl_gamma_able)
        return;

#if USE_GAMMA_RAMPS
    int i;

    for (i = 0; i < 256; i++) {
        vid_gamma_red[i] =
                CLAMP(0, (int) ((255 * pow((i + 0.5)/255.5, vid_gamma.value) + 0.5) * vid_contrast.value), 255) << 8;
        vid_gamma_green[i] = vid_gamma_red[i];
        vid_gamma_blue[i] = vid_gamma_red[i];
    }
#endif
    VID_Gamma_SetGamma();
}

/*
================
VID_Gamma_Init -- call on init
================
*/
static void VID_Gamma_Init(void) {
    vid_gamma.inscribe();
    vid_contrast.inscribe();
    vid_gamma.set_callback(VID_Gamma_f);
    vid_contrast.set_callback(VID_Gamma_f);

    if (gl_glsl_gamma_able)
        return;

#if defined(USE_SDL2)
# if USE_GAMMA_RAMPS
    gammaworks = (SDL_GetWindowGammaRamp(draw_context, vid_sysgamma_red, vid_sysgamma_green, vid_sysgamma_blue) == 0);
    if (gammaworks)
        gammaworks = (SDL_SetWindowGammaRamp(draw_context, vid_sysgamma_red, vid_sysgamma_green, vid_sysgamma_blue) ==
                      0);
# else
    gammaworks = (SDL_SetWindowBrightness(draw_context, 1) == 0);
# endif
#else /* USE_SDL2 */
# if USE_GAMMA_RAMPS
    gammaworks = (SDL_GetGammaRamp(vid_sysgamma_red, vid_sysgamma_green, vid_sysgamma_blue) == 0);
    if (gammaworks)
        gammaworks = (SDL_SetGammaRamp(vid_sysgamma_red, vid_sysgamma_green, vid_sysgamma_blue) == 0);
# else
    gammaworks = (SDL_SetGamma(1, 1, 1) == 0);
# endif
#endif /* USE_SDL2 */

    if (!gammaworks)
        console::safe_print("gamma adjustment not available\n");
}

/*
======================
VID_GetCurrentWidth
======================
*/
static int VID_GetCurrentWidth(void) {
#if defined(USE_SDL2)
    int w = 0, h = 0;
    SDL_GetWindowSize(draw_context, &w, &h);
    return w;
#else
    return draw_context->w;
#endif
}

/*
=======================
VID_GetCurrentHeight
=======================
*/
static int VID_GetCurrentHeight(void) {
#if defined(USE_SDL2)
    int w = 0, h = 0;
    SDL_GetWindowSize(draw_context, &w, &h);
    return h;
#else
    return draw_context->h;
#endif
}

/*
====================
VID_GetCurrentRefreshRate
====================
*/
static int VID_GetCurrentRefreshRate(void) {
#if defined(USE_SDL2)
    SDL_DisplayMode mode;
    int current_display;

    current_display = SDL_GetWindowDisplayIndex(draw_context);

    if (0 != SDL_GetCurrentDisplayMode(current_display, &mode))
        return DEFAULT_REFRESHRATE;

    return mode.refresh_rate;
#else
    // SDL1.2 doesn't support refresh rates
    return DEFAULT_REFRESHRATE;
#endif
}


/*
====================
VID_GetCurrentBPP
====================
*/
static int VID_GetCurrentBPP(void) {
#if defined(USE_SDL2)
    const Uint32 pixelFormat = SDL_GetWindowPixelFormat(draw_context);
    return SDL_BITSPERPIXEL(pixelFormat);
#else
    return draw_context->format->BitsPerPixel;
#endif
}

/*
====================
VID_GetFullscreen

returns true if we are in regular fullscreen or "desktop fullscren"
====================
*/
static bool VID_GetFullscreen(void) {
#if defined(USE_SDL2)
    return (SDL_GetWindowFlags(draw_context) & SDL_WINDOW_FULLSCREEN) != 0;
#else
    return (draw_context->flags & SDL_FULLSCREEN) != 0;
#endif
}

/*
====================
VID_GetDesktopFullscreen

returns true if we are specifically in "desktop fullscreen" mode
====================
*/
static bool VID_GetDesktopFullscreen(void) {
#if defined(USE_SDL2)
    return (SDL_GetWindowFlags(draw_context) & SDL_WINDOW_FULLSCREEN_DESKTOP) == SDL_WINDOW_FULLSCREEN_DESKTOP;
#else
    return false;
#endif
}

/*
====================
VID_GetVSync
====================
*/
static bool VID_GetVSync(void) {
#if defined(USE_SDL2)
    return SDL_GL_GetSwapInterval() == 1;
#else
    int swap_control;
    if (SDL_GL_GetAttribute(SDL_GL_SWAP_CONTROL, &swap_control) == 0)
        return swap_control > 0;
    return false;
#endif
}

/*
====================
VID_GetWindow

used by pl_win.c
====================
*/
void *VID_GetWindow(void) {
#if defined(USE_SDL2)
    return draw_context;
#else
    return NULL;
#endif
}

/*
====================
VID_HasMouseOrInputFocus
====================
*/
bool VID_HasMouseOrInputFocus(void) {
#if defined(USE_SDL2)
    return (SDL_GetWindowFlags(draw_context) & (SDL_WINDOW_MOUSE_FOCUS | SDL_WINDOW_INPUT_FOCUS)) != 0;
#else
    return (SDL_GetAppState() & (SDL_APPMOUSEFOCUS | SDL_APPINPUTFOCUS)) != 0;
#endif
}

/*
====================
VID_IsMinimized
====================
*/
bool VID_IsMinimized(void) {
#if defined(USE_SDL2)
    return !(SDL_GetWindowFlags(draw_context) & SDL_WINDOW_SHOWN);
#else
    /* SDL_APPACTIVE in SDL 1.x means "not minimized" */
    return !(SDL_GetAppState() & SDL_APPACTIVE);
#endif
}

#if defined(USE_SDL2)
/*
================
VID_SDL2_GetDisplayMode

Returns a pointer to a statically allocated SDL_DisplayMode structure
if there is one with the requested params on the default display.
Otherwise returns NULL.

This is passed to SDL_SetWindowDisplayMode to specify a pixel format
with the requested bpp. If we didn't care about bpp we could just pass NULL.
================
*/
static SDL_DisplayMode *VID_SDL2_GetDisplayMode(int width, int height, int refreshrate, int bpp) {
    static SDL_DisplayMode mode;
    const int sdlmodes = SDL_GetNumDisplayModes(0);
    int i;

    for (i = 0; i < sdlmodes; i++) {
        if (SDL_GetDisplayMode(0, i, &mode) != 0)
            continue;

        if (mode.w == width && mode.h == height
            && SDL_BITSPERPIXEL(mode.format) == bpp
            && mode.refresh_rate == refreshrate) {
            return &mode;
        }
    }
    return NULL;
}
#endif /* USE_SDL2 */

/*
================
VID_ValidMode
================
*/
static bool VID_ValidMode(int width, int height, int refreshrate, int bpp, bool fullscreen) {
    // ignore width / height / bpp if vid_desktopfullscreen is enabled
    if (fullscreen && vid_desktopfullscreen.value)
        return true;

    if (width < 320)
        return false;

    if (height < 200)
        return false;

#if defined(USE_SDL2)
    if (fullscreen && VID_SDL2_GetDisplayMode(width, height, refreshrate, bpp) == NULL)
        bpp = 0;
#else
    {
        Uint32 flags = DEFAULT_SDL_FLAGS;
        if (fullscreen)
            flags |= SDL_FULLSCREEN;

        bpp = SDL_VideoModeOK(width, height, bpp, flags);
    }
#endif

    switch (bpp) {
        case 16:
        case 24:
        case 32:
            break;
        default:
            return false;
    }

    return true;
}

/*
================
VID_SetMode
================
*/
static bool VID_SetMode(int width, int height, int refreshrate, int bpp, bool fullscreen) {
    int temp;
    Uint32 flags;
    char caption[50];
    int depthbits, stencilbits;
    int fsaa_obtained;
#if defined(USE_SDL2)
    int previous_display;
#endif

    // so console::infos don't mess us up by forcing vid and snd updates
    temp = scr_disabled_for_loading;
    scr_disabled_for_loading = true;

    CDAudio_Pause();
    music::pause();

    /* z-buffer depth */
    if (bpp == 16) {
        depthbits = 16;
        stencilbits = 0;
    } else {
        depthbits = 24;
        stencilbits = 8;
    }
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, depthbits);
    SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, stencilbits);

    /* fsaa */
    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, fsaa > 0 ? 1 : 0);
    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, fsaa);

    q_snprintf(caption, sizeof(caption), "QuakeSpasm " QUAKESPASM_VER_STRING);

#if defined(USE_SDL2)
    /* Create the window if needed, hidden */
    if (!draw_context) {
        flags = SDL_WINDOW_OPENGL | SDL_WINDOW_HIDDEN;

        if (vid_borderless.value)
            flags |= SDL_WINDOW_BORDERLESS;

        draw_context = SDL_CreateWindow(caption, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height,
                                        flags);
        if (!draw_context) {
            // scale back fsaa
            SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 0);
            SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 0);
            draw_context = SDL_CreateWindow(caption, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height,
                                            flags);
        }
        if (!draw_context) {
            // scale back SDL_GL_DEPTH_SIZE
            SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
            draw_context = SDL_CreateWindow(caption, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height,
                                            flags);
        }
        if (!draw_context) {
            // scale back SDL_GL_STENCIL_SIZE
            SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
            draw_context = SDL_CreateWindow(caption, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height,
                                            flags);
        }
        if (!draw_context)
            Sys_Error("Couldn't create window");

        previous_display = -1;
    } else {
        previous_display = SDL_GetWindowDisplayIndex(draw_context);
    }

    /* Ensure the window is not fullscreen */
    if (VID_GetFullscreen()) {
        if (SDL_SetWindowFullscreen(draw_context, 0) != 0)
            Sys_Error("Couldn't set fullscreen state mode");
    }

    /* Set window size and display mode */
    SDL_SetWindowSize(draw_context, width, height);
    if (previous_display >= 0)
        SDL_SetWindowPosition(draw_context, SDL_WINDOWPOS_CENTERED_DISPLAY(previous_display),
                              SDL_WINDOWPOS_CENTERED_DISPLAY(previous_display));
    else
        SDL_SetWindowPosition(draw_context, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
    SDL_SetWindowDisplayMode(draw_context, VID_SDL2_GetDisplayMode(width, height, refreshrate, bpp));
    SDL_SetWindowBordered(draw_context, vid_borderless.value ? SDL_FALSE : SDL_TRUE);

    /* Make window fullscreen if needed, and show the window */

    if (fullscreen) {
        const Uint32 flag = vid_desktopfullscreen.value ? SDL_WINDOW_FULLSCREEN_DESKTOP : SDL_WINDOW_FULLSCREEN;
        if (SDL_SetWindowFullscreen(draw_context, flag) != 0)
            Sys_Error("Couldn't set fullscreen state mode");
    }

    SDL_ShowWindow(draw_context);
    SDL_RaiseWindow(draw_context);

    /* Create GL context if needed */
    if (!gl_context) {
        gl_context = SDL_GL_CreateContext(draw_context);
        if (!gl_context)
            Sys_Error("Couldn't create GL context");
    }

    gl_swap_control = true;
    if (SDL_GL_SetSwapInterval((vid_vsync.value) ? 1 : 0) == -1)
        gl_swap_control = false;

#else /* !defined(USE_SDL2) */

    flags = DEFAULT_SDL_FLAGS;
    if (fullscreen)
        flags |= SDL_FULLSCREEN;
    if (vid_borderless.value)
        flags |= SDL_NOFRAME;

    gl_swap_control = true;
    if (SDL_GL_SetAttribute(SDL_GL_SWAP_CONTROL, (vid_vsync.value) ? 1 : 0) == -1)
        gl_swap_control = false;

    bpp = SDL_VideoModeOK(width, height, bpp, flags);

    draw_context = SDL_SetVideoMode(width, height, bpp, flags);
    if (!draw_context) {
        // scale back fsaa
        SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 0);
        SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 0);
        draw_context = SDL_SetVideoMode(width, height, bpp, flags);
    }
    if (!draw_context) {
        // scale back SDL_GL_DEPTH_SIZE
        SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
        draw_context = SDL_SetVideoMode(width, height, bpp, flags);
    }
    if (!draw_context) {
        // scale back SDL_GL_STENCIL_SIZE
        SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
        draw_context = SDL_SetVideoMode(width, height, bpp, flags);
        if (!draw_context)
            Sys_Error("Couldn't set video mode");
    }

    SDL_WM_SetCaption(caption, caption);
#endif /* !defined(USE_SDL2) */

    vid.width = VID_GetCurrentWidth();
    vid.height = VID_GetCurrentHeight();
    vid.conwidth = vid.width & 0xFFFFFFF8;
    vid.conheight = vid.conwidth * vid.height / vid.width;
    vid.numpages = 2;

    // read the obtained z-buffer depth
    if (SDL_GL_GetAttribute(SDL_GL_DEPTH_SIZE, &depthbits) == -1)
        depthbits = 0;

    // read obtained fsaa samples
    if (SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &fsaa_obtained) == -1)
        fsaa_obtained = 0;

    // read stencil bits
    if (SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &gl_stencilbits) == -1)
        gl_stencilbits = 0;

    modestate = VID_GetFullscreen() ? MS_FULLSCREEN : MS_WINDOWED;

    CDAudio_Resume();
    music::resume();
    scr_disabled_for_loading = temp;

    // fix the leftover Alt from any Alt-Tab or the like that switched us away
    ClearAllStates();

    console::safe_print("Video mode %dx%dx%d %dHz (%d-bit z-buffer, %dx FSAA) initialized\n",
                   VID_GetCurrentWidth(),
                   VID_GetCurrentHeight(),
                   VID_GetCurrentBPP(),
                   VID_GetCurrentRefreshRate(),
                   depthbits,
                   fsaa_obtained);

    vid.recalc_refdef = 1;

    // no pending changes
    vid_changed = false;

    return true;
}

/*
===================
VID_Changed_f -- kristian -- notify us that a value has changed that requires a vid_restart
===================
*/
static void VID_Changed_f(convar *var) {
    vid_changed = true;
}

/*
===================
VID_Restart -- johnfitz -- change video modes on the fly
===================
*/
static void VID_Restart(void) {
    int width, height, refreshrate, bpp;
    bool fullscreen;

    if (vid_locked || !vid_changed)
        return;

    width = (int) vid_width.value;
    height = (int) vid_height.value;
    refreshrate = (int) vid_refreshrate.value;
    bpp = (int) vid_bpp.value;
    fullscreen = vid_fullscreen.value ? true : false;

    //
    // validate new mode
    //
    if (!VID_ValidMode(width, height, refreshrate, bpp, fullscreen)) {
        console::info("%dx%dx%d %dHz %s is not a valid mode\n",
                   width, height, bpp, refreshrate, fullscreen ? "fullscreen" : "windowed");
        return;
    }

    // ericw -- OS X, SDL1: textures, VBO's invalid after mode change
    //          OS X, SDL2: still valid after mode change
    // To handle both cases, delete all GL objects (textures, VBO, GLSL) now.
    // We must not interleave deleting the old objects with creating new ones, because
    // one of the new objects could be given the same ID as an invalid handle
    // which is later deleted.

    TexMgr_DeleteTextureObjects();
    GLSLGamma_DeleteTexture();
    R_ScaleView_DeleteTexture();
    R_DeleteShaders();
    GL_DeleteBModelVertexBuffer();
    GLMesh_DeleteVertexBuffers();

    //
    // set new mode
    //
    VID_SetMode(width, height, refreshrate, bpp, fullscreen);

    GL_Init();
    TexMgr_ReloadImages();
    GL_BuildBModelVertexBuffer();
    GLMesh_LoadVertexBuffers();
    GL_SetupState();
    Fog_SetupState();

    //warpimages needs to be recalculated
    TexMgr_RecalcWarpImageSize();

    //conwidth and conheight need to be recalculated
    vid.conwidth = (scr_conwidth.value > 0)
                       ? (int) scr_conwidth.value
                       : (scr_conscale.value > 0)
                             ? (int) (vid.width / scr_conscale.value)
                             : vid.width;
    vid.conwidth = std::clamp(vid.conwidth, 320, vid.width);
    vid.conwidth &= 0xFFFFFFF8;
    vid.conheight = vid.conwidth * vid.height / vid.width;
    //
    // keep cvars in line with actual mode
    //
    VID_SyncCvars();
    //
    // update mouse grab
    //
    if (key_dest == key_console || key_dest == key_menu) {
        if (modestate == MS_WINDOWED)
            IN_Deactivate(true);
        else if (modestate == MS_FULLSCREEN)
            IN_Activate();
    }
}

/*
================
VID_Test -- johnfitz -- like vid_restart, but asks for confirmation after switching modes
================
*/
static void VID_Test(void) {
    int old_width, old_height, old_refreshrate, old_bpp, old_fullscreen;

    if (vid_locked || !vid_changed)
        return;
    //
    // now try the switch
    //
    old_width = VID_GetCurrentWidth();
    old_height = VID_GetCurrentHeight();
    old_refreshrate = VID_GetCurrentRefreshRate();
    old_bpp = VID_GetCurrentBPP();
    old_fullscreen = VID_GetFullscreen() ? true : false;

    VID_Restart();

    //pop up confirmation dialoge
    if (!SCR_ModalMessage("Would you like to keep this\nvideo mode? (y/n)\n", 5.0f)) {
        //revert cvars and mode
        vid_width.set_value(old_width);
        vid_height.set_value(old_height);
        vid_refreshrate.set_value(old_refreshrate);
        vid_bpp.set_value(old_bpp);
        vid_fullscreen.set(old_fullscreen ? "1" : "0");
        VID_Restart();
    }
}

/*
================
VID_Unlock -- johnfitz
================
*/
static void VID_Unlock(void) {
    vid_locked = false;
    VID_SyncCvars();
}

/*
================
VID_Lock -- ericw

Subsequent changes to vid_* mode settings, and vid_restart commands, will
be ignored until the "vid_unlock" command is run.

Used when changing gamedirs so the current settings override what was saved
in the config.cfg.
================
*/
void VID_Lock(void) {
    vid_locked = true;
}

//==============================================================================
//
//	OPENGL STUFF
//
//==============================================================================

/*
===============
GL_MakeNiceExtensionsList -- johnfitz
===============
*/
static char *GL_MakeNiceExtensionsList(const char *in) {
    char *copy, *token, *out;
    int i, count;

    if (!in) return Z_Strdup("(none)");

    //each space will be replaced by 4 chars, so count the spaces before we malloc
    for (i = 0, count = 1; i < (int) strlen(in); i++) {
        if (in[i] == ' ')
            count++;
    }

    out = (char *) Z_Malloc(strlen(in) + count * 3 + 1); //usually about 1-2k
    out[0] = 0;

    copy = (char *) Z_Strdup(in);
    for (token = strtok(copy, " "); token; token = strtok(NULL, " ")) {
        strcat(out, "\n   ");
        strcat(out, token);
    }

    Z_Free(copy);
    return out;
}

/*
===============
GL_Info_f -- johnfitz
===============
*/
static void GL_Info_f(void) {
    console::safe_print("GL_VENDOR: %s\n", gl_vendor);
    console::safe_print("GL_RENDERER: %s\n", gl_renderer);
    console::safe_print("GL_VERSION: %s\n", gl_version);
    console::info("GL_EXTENSIONS: %s\n", gl_extensions_nice);
}

/*
===============
GL_CheckExtensions
===============
*/
static bool GL_ParseExtensionList(const char *list, const char *name) {
    const char *start;
    const char *where, *terminator;

    if (!list || !name || !*name)
        return false;
    if (strchr(name, ' ') != NULL)
        return false; // extension names must not have spaces

    start = list;
    while (1) {
        where = strstr(start, name);
        if (!where)
            break;
        terminator = where + strlen(name);
        if (where == start || where[-1] == ' ')
            if (*terminator == ' ' || *terminator == '\0')
                return true;
        start = terminator;
    }
    return false;
}

static void GL_CheckExtensions(void) {
    int swap_control;

    // ARB_vertex_buffer_object
    //
    if (common::check_param("-novbo").has_value())
        console::warn("Vertex buffer objects disabled at command line\n");
    else if (gl_version_major < 1 || (gl_version_major == 1 && gl_version_minor < 5))
        console::warn("OpenGL version < 1.5, skipping ARB_vertex_buffer_object check\n");
    else {
        GL_BindBufferFunc = (PFNGLBINDBUFFERARBPROC) SDL_GL_GetProcAddress("glBindBufferARB");
        GL_BufferDataFunc = (PFNGLBUFFERDATAARBPROC) SDL_GL_GetProcAddress("glBufferDataARB");
        GL_BufferSubDataFunc = (PFNGLBUFFERSUBDATAARBPROC) SDL_GL_GetProcAddress("glBufferSubDataARB");
        GL_DeleteBuffersFunc = (PFNGLDELETEBUFFERSARBPROC) SDL_GL_GetProcAddress("glDeleteBuffersARB");
        GL_GenBuffersFunc = (PFNGLGENBUFFERSARBPROC) SDL_GL_GetProcAddress("glGenBuffersARB");
        if (GL_BindBufferFunc && GL_BufferDataFunc && GL_BufferSubDataFunc && GL_DeleteBuffersFunc &&
            GL_GenBuffersFunc) {
            console::info("FOUND: ARB_vertex_buffer_object\n");
            gl_vbo_able = true;
        } else {
            console::warn("ARB_vertex_buffer_object not available\n");
        }
    }

    // multitexture
    //
    if (common::check_param("-nomtex").has_value())
        console::warn("Mutitexture disabled at command line\n");
    else if (GL_ParseExtensionList(gl_extensions, "GL_ARB_multitexture")) {
        GL_MTexCoord2fFunc = (PFNGLMULTITEXCOORD2FARBPROC) SDL_GL_GetProcAddress("glMultiTexCoord2fARB");
        GL_SelectTextureFunc = (PFNGLACTIVETEXTUREARBPROC) SDL_GL_GetProcAddress("glActiveTextureARB");
        GL_ClientActiveTextureFunc = (PFNGLCLIENTACTIVETEXTUREARBPROC)
                SDL_GL_GetProcAddress("glClientActiveTextureARB");
        if (GL_MTexCoord2fFunc && GL_SelectTextureFunc && GL_ClientActiveTextureFunc) {
            console::info("FOUND: ARB_multitexture\n");
            gl_mtexable = true;

            glGetIntegerv(GL_MAX_TEXTURE_UNITS, &gl_max_texture_units);
            console::info("GL_MAX_TEXTURE_UNITS: %d\n", (int) gl_max_texture_units);
        } else {
            console::warn("Couldn't link to multitexture functions\n");
        }
    } else {
        console::warn("multitexture not supported (extension not found)\n");
    }

    // texture_env_combine
    //
    if (common::check_param("-nocombine").has_value())
        console::warn("texture_env_combine disabled at command line\n");
    else if (GL_ParseExtensionList(gl_extensions, "GL_ARB_texture_env_combine")) {
        console::info("FOUND: ARB_texture_env_combine\n");
        gl_texture_env_combine = true;
    } else if (GL_ParseExtensionList(gl_extensions, "GL_EXT_texture_env_combine")) {
        console::info("FOUND: EXT_texture_env_combine\n");
        gl_texture_env_combine = true;
    } else {
        console::warn("texture_env_combine not supported\n");
    }

    // texture_env_add
    //
    if (common::check_param("-noadd").has_value())
        console::warn("texture_env_add disabled at command line\n");
    else if (GL_ParseExtensionList(gl_extensions, "GL_ARB_texture_env_add")) {
        console::info("FOUND: ARB_texture_env_add\n");
        gl_texture_env_add = true;
    } else if (GL_ParseExtensionList(gl_extensions, "GL_EXT_texture_env_add")) {
        console::info("FOUND: EXT_texture_env_add\n");
        gl_texture_env_add = true;
    } else {
        console::warn("texture_env_add not supported\n");
    }

    // swap control
    //
    if (!gl_swap_control) {
#if defined(USE_SDL2)
        console::warn("vertical sync not supported (SDL_GL_SetSwapInterval failed)\n");
#else
        console::warn("vertical sync not supported (SDL_GL_SetAttribute failed)\n");
#endif
    }
#if defined(USE_SDL2)
	else if ((swap_control = SDL_GL_GetSwapInterval()) == -1)
#else
    else if (SDL_GL_GetAttribute(SDL_GL_SWAP_CONTROL, &swap_control) == -1)
#endif
    {
        gl_swap_control = false;
#if defined(USE_SDL2)
        console::warn("vertical sync not supported (SDL_GL_GetSwapInterval failed)\n");
#else
        console::warn("vertical sync not supported (SDL_GL_GetAttribute failed)\n");
#endif
    } else if ((vid_vsync.value && swap_control != 1) || (!vid_vsync.value && swap_control != 0)) {
        gl_swap_control = false;
        console::warn("vertical sync not supported (swap_control doesn't match vid_vsync)\n");
    } else {
#if defined(USE_SDL2)
        console::info("FOUND: SDL_GL_SetSwapInterval\n");
#else
        console::info("FOUND: SDL_GL_SWAP_CONTROL\n");
#endif
    }

    // anisotropic filtering
    //
    if (GL_ParseExtensionList(gl_extensions, "GL_EXT_texture_filter_anisotropic")) {
        float test1, test2;
        GLuint tex;

        // test to make sure we really have control over it
        // 1.0 and 2.0 should always be legal values
        glGenTextures(1, &tex);
        glBindTexture(GL_TEXTURE_2D, tex);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 1.0f);
        glGetTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, &test1);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 2.0f);
        glGetTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, &test2);
        glDeleteTextures(1, &tex);

        if (test1 == 1 && test2 == 2) {
            console::info("FOUND: EXT_texture_filter_anisotropic\n");
            gl_anisotropy_able = true;
        } else {
            console::warn("anisotropic filtering locked by driver. Current driver setting is %f\n", test1);
        }

        //get max value either way, so the menu and stuff know it
        glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &gl_max_anisotropy);
        if (gl_max_anisotropy < 2) {
            gl_anisotropy_able = false;
            gl_max_anisotropy = 1;
            console::warn("anisotropic filtering broken: disabled\n");
        }
    } else {
        gl_max_anisotropy = 1;
        console::warn("texture_filter_anisotropic not supported\n");
    }

    // texture_non_power_of_two
    //
    if (common::check_param("-notexturenpot").has_value())
        console::warn("texture_non_power_of_two disabled at command line\n");
    else if (GL_ParseExtensionList(gl_extensions, "GL_ARB_texture_non_power_of_two")) {
        console::info("FOUND: ARB_texture_non_power_of_two\n");
        gl_texture_NPOT = true;
    } else {
        console::warn("texture_non_power_of_two not supported\n");
    }

    // GLSL
    //
    if (common::check_param("-noglsl").has_value())
        console::warn("GLSL disabled at command line\n");
    else if (gl_version_major >= 2) {
        GL_CreateShaderFunc = (QS_PFNGLCREATESHADERPROC) SDL_GL_GetProcAddress("glCreateShader");
        GL_DeleteShaderFunc = (QS_PFNGLDELETESHADERPROC) SDL_GL_GetProcAddress("glDeleteShader");
        GL_DeleteProgramFunc = (QS_PFNGLDELETEPROGRAMPROC) SDL_GL_GetProcAddress("glDeleteProgram");
        GL_ShaderSourceFunc = (QS_PFNGLSHADERSOURCEPROC) SDL_GL_GetProcAddress("glShaderSource");
        GL_CompileShaderFunc = (QS_PFNGLCOMPILESHADERPROC) SDL_GL_GetProcAddress("glCompileShader");
        GL_GetShaderivFunc = (QS_PFNGLGETSHADERIVPROC) SDL_GL_GetProcAddress("glGetShaderiv");
        GL_GetShaderInfoLogFunc = (QS_PFNGLGETSHADERINFOLOGPROC) SDL_GL_GetProcAddress("glGetShaderInfoLog");
        GL_GetProgramivFunc = (QS_PFNGLGETPROGRAMIVPROC) SDL_GL_GetProcAddress("glGetProgramiv");
        GL_GetProgramInfoLogFunc = (QS_PFNGLGETPROGRAMINFOLOGPROC) SDL_GL_GetProcAddress("glGetProgramInfoLog");
        GL_CreateProgramFunc = (QS_PFNGLCREATEPROGRAMPROC) SDL_GL_GetProcAddress("glCreateProgram");
        GL_AttachShaderFunc = (QS_PFNGLATTACHSHADERPROC) SDL_GL_GetProcAddress("glAttachShader");
        GL_LinkProgramFunc = (QS_PFNGLLINKPROGRAMPROC) SDL_GL_GetProcAddress("glLinkProgram");
        GL_BindAttribLocationFunc = (QS_PFNGLBINDATTRIBLOCATIONFUNC) SDL_GL_GetProcAddress("glBindAttribLocation");
        GL_UseProgramFunc = (QS_PFNGLUSEPROGRAMPROC) SDL_GL_GetProcAddress("glUseProgram");
        GL_GetAttribLocationFunc = (QS_PFNGLGETATTRIBLOCATIONPROC) SDL_GL_GetProcAddress("glGetAttribLocation");
        GL_VertexAttribPointerFunc = (QS_PFNGLVERTEXATTRIBPOINTERPROC) SDL_GL_GetProcAddress("glVertexAttribPointer");
        GL_EnableVertexAttribArrayFunc = (QS_PFNGLENABLEVERTEXATTRIBARRAYPROC) SDL_GL_GetProcAddress(
            "glEnableVertexAttribArray");
        GL_DisableVertexAttribArrayFunc = (QS_PFNGLDISABLEVERTEXATTRIBARRAYPROC) SDL_GL_GetProcAddress(
            "glDisableVertexAttribArray");
        GL_GetUniformLocationFunc = (QS_PFNGLGETUNIFORMLOCATIONPROC) SDL_GL_GetProcAddress("glGetUniformLocation");
        GL_Uniform1iFunc = (QS_PFNGLUNIFORM1IPROC) SDL_GL_GetProcAddress("glUniform1i");
        GL_Uniform1fFunc = (QS_PFNGLUNIFORM1FPROC) SDL_GL_GetProcAddress("glUniform1f");
        GL_Uniform3fFunc = (QS_PFNGLUNIFORM3FPROC) SDL_GL_GetProcAddress("glUniform3f");
        GL_Uniform4fFunc = (QS_PFNGLUNIFORM4FPROC) SDL_GL_GetProcAddress("glUniform4f");

        if (GL_CreateShaderFunc &&
            GL_DeleteShaderFunc &&
            GL_DeleteProgramFunc &&
            GL_ShaderSourceFunc &&
            GL_CompileShaderFunc &&
            GL_GetShaderivFunc &&
            GL_GetShaderInfoLogFunc &&
            GL_GetProgramivFunc &&
            GL_GetProgramInfoLogFunc &&
            GL_CreateProgramFunc &&
            GL_AttachShaderFunc &&
            GL_LinkProgramFunc &&
            GL_BindAttribLocationFunc &&
            GL_UseProgramFunc &&
            GL_GetAttribLocationFunc &&
            GL_VertexAttribPointerFunc &&
            GL_EnableVertexAttribArrayFunc &&
            GL_DisableVertexAttribArrayFunc &&
            GL_GetUniformLocationFunc &&
            GL_Uniform1iFunc &&
            GL_Uniform1fFunc &&
            GL_Uniform3fFunc &&
            GL_Uniform4fFunc) {
            console::info("FOUND: GLSL\n");
            gl_glsl_able = true;
        } else {
            console::warn("GLSL not available\n");
        }
    } else {
        console::warn("OpenGL version < 2, GLSL not available\n");
    }
    // GLSL gamma
    //
    if (common::check_param("-noglslgamma").has_value())
        console::warn("GLSL gamma disabled at command line\n");
    else if (gl_glsl_able) {
        gl_glsl_gamma_able = true;
        console::info("Enabled: GLSL gamma\n");
    } else {
        console::warn("GLSL gamma not available, using hardware gamma\n");
    }
    // GLSL alias model rendering
    //
    if (common::check_param("-noglslalias").has_value())
        console::warn("GLSL alias model rendering disabled at command line\n");
    else if (gl_glsl_able && gl_vbo_able && gl_max_texture_units >= 3) {
        gl_glsl_alias_able = true;
        console::info("Enabled: GLSL alias model rendering\n");
    } else {
        console::warn("GLSL alias model rendering not available, using Fitz renderer\n");
    }

    // packed_pixels
    //
    if (common::check_param("-nopackedpixels").has_value())
        console::warn("EXT_packed_pixels disabled at command line\n");
    else if (gl_glsl_alias_able) {
        gl_packed_pixels = true;
        console::info("Enabled: EXT_packed_pixels\n");
    }
#if 0 /* Disabling for non-GLSL path, needs more surgery. */
	else if (GL_ParseExtensionList(gl_extensions, "GL_APPLE_packed_pixels")) {
        console::info("FOUND: APPLE_packed_pixels\n");
        gl_packed_pixels = true;
    } else if (GL_ParseExtensionList(gl_extensions, "GL_EXT_packed_pixels")) {
        console::info("FOUND: EXT_packed_pixels\n");
        gl_packed_pixels = true;
    } else {
        console::warn("packed_pixels not supported\n");
    }
#endif

    // glGenerateMipmap for warp textures
    if (common::check_param("-nowarpmipmaps").has_value())
        console::warn("glGenerateMipmap disabled at command line\n");
    else {
        if (gl_version_major >= 3 || GL_ParseExtensionList(gl_extensions, "GL_ARB_framebuffer_object")) {
            GL_GenerateMipmap = (QS_PFNGENERATEMIPMAP) SDL_GL_GetProcAddress("glGenerateMipmap");
            if (GL_GenerateMipmap != NULL)
                console::info("FOUND: glGenerateMipmap\n");
        } else if (GL_ParseExtensionList(gl_extensions, "GL_EXT_framebuffer_object")) {
            GL_GenerateMipmap = (QS_PFNGENERATEMIPMAP) SDL_GL_GetProcAddress("glGenerateMipmapEXT");
            if (GL_GenerateMipmap != NULL)
                console::info("FOUND: glGenerateMipmapEXT\n");
        }
        if (GL_GenerateMipmap == NULL)
            console::warn("glGenerateMipmap not available, liquids won't have mipmaps\n");
    }
}

/*
===============
GL_SetupState -- johnfitz

does all the stuff from GL_Init that needs to be done every time a new GL render context is created
===============
*/
static void GL_SetupState(void) {
    glClearColor(0.15, 0.15, 0.15, 0); //johnfitz -- originally 1,0,0,0
    glCullFace(GL_BACK); //johnfitz -- glquake used CCW with backwards culling -- let's do it right
    glFrontFace(GL_CW); //johnfitz -- glquake used CCW with backwards culling -- let's do it right
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_ALPHA_TEST);
    glAlphaFunc(GL_GREATER, 0.666);
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    glShadeModel(GL_FLAT);
    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); //johnfitz
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glDepthRange(0, 1); //johnfitz -- moved here becuase gl_ztrick is gone.
    glDepthFunc(GL_LEQUAL); //johnfitz -- moved here becuase gl_ztrick is gone.
}

/*
===============
GL_Init
===============
*/
static void GL_Init(void) {
    gl_vendor = (const char *) glGetString(GL_VENDOR);
    gl_renderer = (const char *) glGetString(GL_RENDERER);
    gl_version = (const char *) glGetString(GL_VERSION);
    gl_extensions = (const char *) glGetString(GL_EXTENSIONS);

    console::safe_print("GL_VENDOR: %s\n", gl_vendor);
    console::safe_print("GL_RENDERER: %s\n", gl_renderer);
    console::safe_print("GL_VERSION: %s\n", gl_version);

    if (gl_version == NULL || sscanf(gl_version, "%d.%d", &gl_version_major, &gl_version_minor) < 2) {
        gl_version_major = 0;
        gl_version_minor = 0;
    }

    if (gl_extensions_nice != NULL)
        Z_Free(gl_extensions_nice);
    gl_extensions_nice = GL_MakeNiceExtensionsList(gl_extensions);

    GL_CheckExtensions(); //johnfitz

#ifdef __APPLE__
    // ericw -- enable multi-threaded OpenGL, gives a decent FPS boost.
    // https://developer.apple.com/library/mac/technotes/tn2085/
    if (host_parms->numcpus > 1 &&
        kCGLNoError != CGLEnable(CGLGetCurrentContext(), kCGLCEMPEngine)) {
        console::warn("Couldn't enable multi-threaded OpenGL");
    }
#endif

    //johnfitz -- intel video workarounds from Baker
    if (!strcmp(gl_vendor, "Intel")) {
        console::info("Intel Display Adapter detected, enabling gl_clear\n");
        command::buffer::add_text("gl_clear 1");
    }
    //johnfitz

    GLAlias_CreateShaders();
    GLWorld_CreateShaders();
    GL_ClearBufferBindings();
}

/*
=================
GL_BeginRendering -- sets values of glx, gly, glwidth, glheight
=================
*/
void GL_BeginRendering(int *x, int *y, int *width, int *height) {
    *x = *y = 0;
    *width = vid.width;
    *height = vid.height;
}

/*
=================
GL_EndRendering
=================
*/
void GL_EndRendering(void) {
    if (!scr_skipupdate) {
#if defined(USE_SDL2)
        SDL_GL_SwapWindow(draw_context);
#else

        SDL_GL_SwapBuffers();
#endif
    }
}


void VID_Shutdown(void) {
    if (vid_initialized) {
        VID_Gamma_Shutdown(); //johnfitz
#if defined(USE_SDL2)
        SDL_GL_DeleteContext(gl_context);
        gl_context = NULL;
        SDL_DestroyWindow(draw_context);
#endif
        SDL_QuitSubSystem(SDL_INIT_VIDEO);
        draw_context = NULL;
        PL_VID_Shutdown();
    }
}

/*
===================================================================

MAIN WINDOW

===================================================================
*/

/*
================
ClearAllStates
================
*/
static void ClearAllStates(void) {
    Key_ClearStates();
    IN_ClearStates();
}


//==========================================================================
//
//  COMMANDS
//
//==========================================================================

/*
=================
VID_DescribeCurrentMode_f
=================
*/
static void VID_DescribeCurrentMode_f(void) {
    if (draw_context)
        console::info("%dx%dx%d %dHz %s\n",
                   VID_GetCurrentWidth(),
                   VID_GetCurrentHeight(),
                   VID_GetCurrentBPP(),
                   VID_GetCurrentRefreshRate(),
                   VID_GetFullscreen() ? "fullscreen" : "windowed");
}

/*
=================
VID_DescribeModes_f -- johnfitz -- changed formatting, and added refresh rates after each mode.
=================
*/
static void VID_DescribeModes_f(void) {
    int i;
    int lastwidth, lastheight, lastbpp, count;

    lastwidth = lastheight = lastbpp = count = 0;

    for (i = 0; i < nummodes; i++) {
        if (lastwidth != modelist[i].width || lastheight != modelist[i].height || lastbpp != modelist[i].bpp) {
            if (count > 0)
                console::safe_print("\n");
            console::safe_print("   %4i x %4i x %i : %i", modelist[i].width, modelist[i].height, modelist[i].bpp,
                           modelist[i].refreshrate);
            lastwidth = modelist[i].width;
            lastheight = modelist[i].height;
            lastbpp = modelist[i].bpp;
            count++;
        }
    }
    console::info("\n%i modes\n", count);
}

/*
===================
VID_FSAA_f -- ericw -- warn that vid_fsaa requires engine restart
===================
*/
static void VID_FSAA_f(convar *var) {
    // don't print the warning if vid_fsaa is set during startup
    if (vid_initialized)
        console::info("%s %d requires engine restart to take effect\n", var->name.c_str(), (int) var->value);
}

//==========================================================================
//
//  INIT
//
//==========================================================================

/*
=================
VID_InitModelist
=================
*/
static void VID_InitModelist(void) {
#if defined(USE_SDL2)
    const int sdlmodes = SDL_GetNumDisplayModes(0);
    int i;

    nummodes = 0;
    for (i = 0; i < sdlmodes; i++) {
        SDL_DisplayMode mode;

        if (nummodes >= MAX_MODE_LIST)
            break;
        if (SDL_GetDisplayMode(0, i, &mode) == 0) {
            modelist[nummodes].width = mode.w;
            modelist[nummodes].height = mode.h;
            modelist[nummodes].bpp = SDL_BITSPERPIXEL(mode.format);
            modelist[nummodes].refreshrate = mode.refresh_rate;
            nummodes++;
        }
    }
#else /* !defined(USE_SDL2) */
    SDL_PixelFormat format;
    SDL_Rect **modes;
    Uint32 flags;
    int i, j, k, originalnummodes, existingmode;
    int bpps[] = {16, 24, 32}; // enumerate >8 bpp modes

    originalnummodes = nummodes = 0;
    memset(&format, 0, sizeof(format));

    // enumerate fullscreen modes
    flags = DEFAULT_SDL_FLAGS | SDL_FULLSCREEN;
    for (i = 0; i < (int) std::size(bpps); i++) {
        if (nummodes >= MAX_MODE_LIST)
            break;

        format.BitsPerPixel = bpps[i];
        modes = SDL_ListModes(&format, flags);

        if (modes == (SDL_Rect **) 0 || modes == (SDL_Rect **) -1)
            continue;

        for (j = 0; modes[j]; j++) {
            if (modes[j]->w > MAXWIDTH || modes[j]->h > MAXHEIGHT || nummodes >= MAX_MODE_LIST)
                continue;

            modelist[nummodes].width = modes[j]->w;
            modelist[nummodes].height = modes[j]->h;
            modelist[nummodes].bpp = bpps[i];
            modelist[nummodes].refreshrate = DEFAULT_REFRESHRATE;

            for (k = originalnummodes, existingmode = 0; k < nummodes; k++) {
                if ((modelist[nummodes].width == modelist[k].width) &&
                    (modelist[nummodes].height == modelist[k].height) &&
                    (modelist[nummodes].bpp == modelist[k].bpp)) {
                    existingmode = 1;
                    break;
                }
            }

            if (!existingmode) {
                nummodes++;
            }
        }
    }

    if (nummodes == originalnummodes)
        console::safe_print("No fullscreen DIB modes found\n");
#endif /* !defined(USE_SDL2) */
}

/*
===================
VID_Init
===================
*/
void VID_Init(void) {
    static char vid_center[] = "SDL_VIDEO_CENTERED=center";
    int width, height, refreshrate, bpp;
    int display_width, display_height, display_refreshrate, display_bpp;
    bool fullscreen;
    const char *read_vars[] = {
        "vid_fullscreen",
        "vid_width",
        "vid_height",
        "vid_refreshrate",
        "vid_bpp",
        "vid_vsync",
        "vid_fsaa",
        "vid_desktopfullscreen",
        "vid_borderless"
    };
#define num_readvars	std::size(read_vars)

    vid_fullscreen.inscribe(); //johnfitz
    vid_width.inscribe(); //johnfitz
    vid_height.inscribe(); //johnfitz
    vid_refreshrate.inscribe(); //johnfitz
    vid_bpp.inscribe(); //johnfitz
    vid_vsync.inscribe(); //johnfitz
    vid_fsaa.inscribe(); //QuakeSpasm
    vid_desktopfullscreen.inscribe(); //QuakeSpasm
    vid_borderless.inscribe(); //QuakeSpasm
    vid_fullscreen.set_callback(VID_Changed_f);
    vid_width.set_callback(VID_Changed_f);
    vid_height.set_callback(VID_Changed_f);
    vid_refreshrate.set_callback(VID_Changed_f);
    vid_bpp.set_callback(VID_Changed_f);
    vid_vsync.set_callback(VID_Changed_f);
    vid_fsaa.set_callback(VID_FSAA_f);
    vid_desktopfullscreen.set_callback(VID_Changed_f);
    vid_borderless.set_callback(VID_Changed_f);

    command::add("vid_unlock", VID_Unlock); //johnfitz
    command::add("vid_restart", VID_Restart); //johnfitz
    command::add("vid_test", VID_Test); //johnfitz
    command::add("vid_describecurrentmode", VID_DescribeCurrentMode_f);
    command::add("vid_describemodes", VID_DescribeModes_f);

    putenv(vid_center); /* SDL_putenv is problematic in versions <= 1.2.9 */

    if (SDL_InitSubSystem(SDL_INIT_VIDEO) < 0)
        Sys_Error("Couldn't init SDL video: %s", SDL_GetError());

#if defined(USE_SDL2)
    {
        SDL_DisplayMode mode;
        if (SDL_GetDesktopDisplayMode(0, &mode) != 0)
            Sys_Error("Could not get desktop display mode");

        display_width = mode.w;
        display_height = mode.h;
        display_refreshrate = mode.refresh_rate;
        display_bpp = SDL_BITSPERPIXEL(mode.format);
    }
#else
    {
        const SDL_VideoInfo *info = SDL_GetVideoInfo();
        display_width = info->current_w;
        display_height = info->current_h;
        display_refreshrate = DEFAULT_REFRESHRATE;
        display_bpp = info->vfmt->BitsPerPixel;
    }
#endif

    vid_bpp.set_value((float) display_bpp);

    if (CFG_OpenConfig("config.cfg") == 0) {
        CFG_ReadCvars(read_vars, num_readvars);
        CFG_CloseConfig();
    }
    CFG_ReadCvarOverrides(read_vars, num_readvars);

    VID_InitModelist();

    width = (int) vid_width.value;
    height = (int) vid_height.value;
    refreshrate = (int) vid_refreshrate.value;
    bpp = (int) vid_bpp.value;
    fullscreen = (int) vid_fullscreen.value;
    fsaa = (int) vid_fsaa.value;

    if (common::check_param("-current").has_value()) {
        width = display_width;
        height = display_height;
        refreshrate = display_refreshrate;
        bpp = display_bpp;
        fullscreen = true;
    } else {
        auto p = common::check_param("-width");
        if (p.has_value() && p.value() < common::_argv.size() - 1) {
            width = std::atoi(common::_argv[p.value() + 1].c_str());

            if (!common::check_param("-height").has_value())
                height = width * 3 / 4;
        }

        p = common::check_param("-height");
        if (p.has_value() && p.value() < common::_argv.size() - 1) {
            height = std::atoi(common::_argv[p.value() + 1].c_str());

            if (!common::check_param("-width").has_value())
                width = height * 4 / 3;
        }

        p = common::check_param("-refreshrate");
        if (p.has_value() && p.value() < common::_argv.size() - 1)
            refreshrate = std::atoi(common::_argv[p.value() + 1].c_str());

        p = common::check_param("-bpp");
        if (p.has_value() && p.value() < common::_argv.size() - 1)
            bpp = std::atoi(common::_argv[p.value() + 1].c_str());

        if (common::check_param("-window").has_value() || common::check_param("-w").has_value())
            fullscreen = false;
        else if (common::check_param("-fullscreen").has_value() || common::check_param("-f").has_value())
            fullscreen = true;
    }

    auto p = common::check_param("-fsaa");
    if (p.has_value() && p.value() < common::_argv.size() - 1)
        fsaa = atoi(common::_argv[p.value() + 1].c_str());

    if (!VID_ValidMode(width, height, refreshrate, bpp, fullscreen)) {
        width = (int) vid_width.value;
        height = (int) vid_height.value;
        refreshrate = (int) vid_refreshrate.value;
        bpp = (int) vid_bpp.value;
        fullscreen = (int) vid_fullscreen.value;
    }

    if (!VID_ValidMode(width, height, refreshrate, bpp, fullscreen)) {
        width = 640;
        height = 480;
        refreshrate = display_refreshrate;
        bpp = display_bpp;
        fullscreen = false;
    }

    vid_initialized = true;

    vid.maxwarpwidth = WARP_WIDTH;
    vid.maxwarpheight = WARP_HEIGHT;
    vid.colormap = host_colormap;
    vid.fullbright = 256 - LittleLong(*((int *) vid.colormap + 2048));

#if !defined(USE_SDL2)
    // set window icon
    PL_SetWindowIcon();
#endif

    VID_SetMode(width, height, refreshrate, bpp, fullscreen);

#if defined(USE_SDL2)
    // set window icon
    PL_SetWindowIcon();
#endif

    GL_Init();
    GL_SetupState();
    command::add("gl_info", GL_Info_f); //johnfitz

    //johnfitz -- removed code creating "glquake" subdirectory

    vid_menucmdfn = VID_Menu_f; //johnfitz
    vid_menudrawfn = VID_MenuDraw;
    vid_menukeyfn = VID_MenuKey;

    VID_Gamma_Init(); //johnfitz
    VID_Menu_Init(); //johnfitz

    //QuakeSpasm: current vid settings should override config file settings.
    //so we have to lock the vid mode from now until after all config files are read.
    vid_locked = true;
}

// new proc by S.A., called by alt-return key binding.
void VID_Toggle(void) {
    // disabling the fast path completely because SDL_SetWindowFullscreen was changing
    // the window size on SDL2/WinXP and we weren't set up to handle it. --ericw
    //
    // TODO: Clear out the dead code, reinstate the fast path using SDL_SetWindowFullscreen
    // inside VID_SetMode, check window size to fix WinXP issue. This will
    // keep all the mode changing code in one place.
    static bool vid_toggle_works = false;
    bool toggleWorked;
#if defined(USE_SDL2)
    Uint32 flags = 0;
#endif

    S_ClearBuffer();

    if (!vid_toggle_works)
        goto vrestart;
    else if (gl_vbo_able) {
        // disabling the fast path because with SDL 1.2 it invalidates VBOs (using them
        // causes a crash, sugesting that the fullscreen toggle created a new GL context,
        // although texture objects remain valid for some reason).
        //
        // SDL2 does promise window resizes / fullscreen changes preserve the GL context,
        // so we could use the fast path with SDL2. --ericw
        vid_toggle_works = false;
        goto vrestart;
    }

#if defined(USE_SDL2)
    if (!VID_GetFullscreen()) {
        flags = vid_desktopfullscreen.value ? SDL_WINDOW_FULLSCREEN_DESKTOP : SDL_WINDOW_FULLSCREEN;
    }

    toggleWorked = SDL_SetWindowFullscreen(draw_context, flags) == 0;
#else
    toggleWorked = SDL_WM_ToggleFullScreen(draw_context) == 1;
#endif

    if (toggleWorked) {
        Sbar_Changed(); // Sbar seems to need refreshing

        modestate = VID_GetFullscreen() ? MS_FULLSCREEN : MS_WINDOWED;

        VID_SyncCvars();

        // update mouse grab
        if (key_dest == key_console || key_dest == key_menu) {
            if (modestate == MS_WINDOWED)
                IN_Deactivate(true);
            else if (modestate == MS_FULLSCREEN)
                IN_Activate();
        }
    } else {
        vid_toggle_works = false;
        console::debug("SDL_WM_ToggleFullScreen failed, attempting VID_Restart\n");
    vrestart:
        vid_fullscreen.set(VID_GetFullscreen() ? "0" : "1");
        command::buffer::add_text("vid_restart\n");
    }
}

/*
================
VID_SyncCvars -- johnfitz -- set vid cvars to match current video mode
================
*/
void VID_SyncCvars(void) {
    if (draw_context) {
        if (!VID_GetDesktopFullscreen()) {
            vid_width.set_value(VID_GetCurrentWidth());
            vid_height.set_value(VID_GetCurrentHeight());
        }
        vid_refreshrate.set_value(VID_GetCurrentRefreshRate());
        vid_bpp.set_value(VID_GetCurrentBPP());
        vid_fullscreen.set(VID_GetFullscreen() ? "1" : "0");
        // don't sync vid_desktopfullscreen, it's a user preference that
        // should persist even if we are in windowed mode.
        vid_vsync.set(VID_GetVSync() ? "1" : "0");
    }

    vid_changed = false;
}

//==========================================================================
//
//  NEW VIDEO MENU -- johnfitz
//
//==========================================================================

enum {
    VID_OPT_MODE,
    VID_OPT_BPP,
    VID_OPT_REFRESHRATE,
    VID_OPT_FULLSCREEN,
    VID_OPT_VSYNC,
    VID_OPT_TEST,
    VID_OPT_APPLY,
    VIDEO_OPTIONS_ITEMS
};

static int video_options_cursor = 0;

typedef struct {
    int width, height;
} vid_menu_mode;

//TODO: replace these fixed-length arrays with hunk_allocated buffers
static vid_menu_mode vid_menu_modes[MAX_MODE_LIST];
static int vid_menu_nummodes = 0;

static int vid_menu_bpps[MAX_BPPS_LIST];
static int vid_menu_numbpps = 0;

static int vid_menu_rates[MAX_RATES_LIST];
static int vid_menu_numrates = 0;

/*
================
VID_Menu_Init
================
*/
static void VID_Menu_Init(void) {
    int i, j, h, w;

    for (i = 0; i < nummodes; i++) {
        w = modelist[i].width;
        h = modelist[i].height;

        for (j = 0; j < vid_menu_nummodes; j++) {
            if (vid_menu_modes[j].width == w &&
                vid_menu_modes[j].height == h)
                break;
        }

        if (j == vid_menu_nummodes) {
            vid_menu_modes[j].width = w;
            vid_menu_modes[j].height = h;
            vid_menu_nummodes++;
        }
    }
}

/*
================
VID_Menu_RebuildBppList

regenerates bpp list based on current vid_width and vid_height
================
*/
static void VID_Menu_RebuildBppList(void) {
    int i, j, b;

    vid_menu_numbpps = 0;

    for (i = 0; i < nummodes; i++) {
        if (vid_menu_numbpps >= MAX_BPPS_LIST)
            break;

        //bpp list is limited to bpps available with current width/height
        if (modelist[i].width != vid_width.value ||
            modelist[i].height != vid_height.value)
            continue;

        b = modelist[i].bpp;

        for (j = 0; j < vid_menu_numbpps; j++) {
            if (vid_menu_bpps[j] == b)
                break;
        }

        if (j == vid_menu_numbpps) {
            vid_menu_bpps[j] = b;
            vid_menu_numbpps++;
        }
    }

    //if there are no valid fullscreen bpps for this width/height, just pick one
    if (vid_menu_numbpps == 0) {
        vid_bpp.set_value((float) modelist[0].bpp);
        return;
    }

    //if vid_bpp is not in the new list, change vid_bpp
    for (i = 0; i < vid_menu_numbpps; i++)
        if (vid_menu_bpps[i] == (int) (vid_bpp.value))
            break;

    if (i == vid_menu_numbpps)
        vid_bpp.set_value((float) vid_menu_bpps[0]);
}

/*
================
VID_Menu_RebuildRateList

regenerates rate list based on current vid_width, vid_height and vid_bpp
================
*/
static void VID_Menu_RebuildRateList(void) {
    int i, j, r;

    vid_menu_numrates = 0;

    for (i = 0; i < nummodes; i++) {
        //rate list is limited to rates available with current width/height/bpp
        if (modelist[i].width != vid_width.value ||
            modelist[i].height != vid_height.value ||
            modelist[i].bpp != vid_bpp.value)
            continue;

        r = modelist[i].refreshrate;

        for (j = 0; j < vid_menu_numrates; j++) {
            if (vid_menu_rates[j] == r)
                break;
        }

        if (j == vid_menu_numrates) {
            vid_menu_rates[j] = r;
            vid_menu_numrates++;
        }
    }

    //if there are no valid fullscreen refreshrates for this width/height, just pick one
    if (vid_menu_numrates == 0) {
        convar::set_value("vid_refreshrate", (float) modelist[0].refreshrate);
        return;
    }

    //if vid_refreshrate is not in the new list, change vid_refreshrate
    for (i = 0; i < vid_menu_numrates; i++)
        if (vid_menu_rates[i] == (int) (vid_refreshrate.value))
            break;

    if (i == vid_menu_numrates)
        convar::set_value("vid_refreshrate", (float) vid_menu_rates[0]);
}

/*
================
VID_Menu_ChooseNextMode

chooses next resolution in order, then updates vid_width and
vid_height cvars, then updates bpp and refreshrate lists
================
*/
static void VID_Menu_ChooseNextMode(int dir) {
    int i;

    if (vid_menu_nummodes) {
        for (i = 0; i < vid_menu_nummodes; i++) {
            if (vid_menu_modes[i].width == vid_width.value &&
                vid_menu_modes[i].height == vid_height.value)
                break;
        }

        if (i == vid_menu_nummodes) //can't find it in list, so it must be a custom windowed res
        {
            i = 0;
        } else {
            i += dir;
            if (i >= vid_menu_nummodes)
                i = 0;
            else if (i < 0)
                i = vid_menu_nummodes - 1;
        }

        vid_width.set_value((float) vid_menu_modes[i].width);
        vid_height.set_value((float) vid_menu_modes[i].height);
        VID_Menu_RebuildBppList();
        VID_Menu_RebuildRateList();
    }
}

/*
================
VID_Menu_ChooseNextBpp

chooses next bpp in order, then updates vid_bpp cvar
================
*/
static void VID_Menu_ChooseNextBpp(int dir) {
    int i;

    if (vid_menu_numbpps) {
        for (i = 0; i < vid_menu_numbpps; i++) {
            if (vid_menu_bpps[i] == vid_bpp.value)
                break;
        }

        if (i == vid_menu_numbpps) //can't find it in list
        {
            i = 0;
        } else {
            i += dir;
            if (i >= vid_menu_numbpps)
                i = 0;
            else if (i < 0)
                i = vid_menu_numbpps - 1;
        }

        vid_bpp.set_value((float) vid_menu_bpps[i]);
    }
}

/*
================
VID_Menu_ChooseNextRate

chooses next refresh rate in order, then updates vid_refreshrate cvar
================
*/
static void VID_Menu_ChooseNextRate(int dir) {
    int i;

    for (i = 0; i < vid_menu_numrates; i++) {
        if (vid_menu_rates[i] == vid_refreshrate.value)
            break;
    }

    if (i == vid_menu_numrates) //can't find it in list
    {
        i = 0;
    } else {
        i += dir;
        if (i >= vid_menu_numrates)
            i = 0;
        else if (i < 0)
            i = vid_menu_numrates - 1;
    }

    convar::set_value("vid_refreshrate", (float) vid_menu_rates[i]);
}

/*
================
VID_MenuKey
================
*/
static void VID_MenuKey(int key) {
    switch (key) {
        case K_ESCAPE:
        case K_BBUTTON:
            VID_SyncCvars(); //sync cvars before leaving menu. FIXME: there are other ways to leave menu
            S_LocalSound("misc/menu1.wav");
            M_Menu_Options_f();
            break;

        case K_UPARROW:
            S_LocalSound("misc/menu1.wav");
            video_options_cursor--;
            if (video_options_cursor < 0)
                video_options_cursor = VIDEO_OPTIONS_ITEMS - 1;
            break;

        case K_DOWNARROW:
            S_LocalSound("misc/menu1.wav");
            video_options_cursor++;
            if (video_options_cursor >= VIDEO_OPTIONS_ITEMS)
                video_options_cursor = 0;
            break;

        case K_LEFTARROW:
            S_LocalSound("misc/menu3.wav");
            switch (video_options_cursor) {
                case VID_OPT_MODE:
                    VID_Menu_ChooseNextMode(1);
                    break;
                case VID_OPT_BPP:
                    VID_Menu_ChooseNextBpp(1);
                    break;
                case VID_OPT_REFRESHRATE:
                    VID_Menu_ChooseNextRate(1);
                    break;
                case VID_OPT_FULLSCREEN:
                    command::buffer::add_text("toggle vid_fullscreen\n");
                    break;
                case VID_OPT_VSYNC:
                    command::buffer::add_text("toggle vid_vsync\n"); // kristian
                    break;
                default:
                    break;
            }
            break;

        case K_RIGHTARROW:
            S_LocalSound("misc/menu3.wav");
            switch (video_options_cursor) {
                case VID_OPT_MODE:
                    VID_Menu_ChooseNextMode(-1);
                    break;
                case VID_OPT_BPP:
                    VID_Menu_ChooseNextBpp(-1);
                    break;
                case VID_OPT_REFRESHRATE:
                    VID_Menu_ChooseNextRate(-1);
                    break;
                case VID_OPT_FULLSCREEN:
                    command::buffer::add_text("toggle vid_fullscreen\n");
                    break;
                case VID_OPT_VSYNC:
                    command::buffer::add_text("toggle vid_vsync\n");
                    break;
                default:
                    break;
            }
            break;

        case K_ENTER:
        case K_KP_ENTER:
        case K_ABUTTON:
            m_entersound = true;
            switch (video_options_cursor) {
                case VID_OPT_MODE:
                    VID_Menu_ChooseNextMode(1);
                    break;
                case VID_OPT_BPP:
                    VID_Menu_ChooseNextBpp(1);
                    break;
                case VID_OPT_REFRESHRATE:
                    VID_Menu_ChooseNextRate(1);
                    break;
                case VID_OPT_FULLSCREEN:
                    command::buffer::add_text("toggle vid_fullscreen\n");
                    break;
                case VID_OPT_VSYNC:
                    command::buffer::add_text("toggle vid_vsync\n");
                    break;
                case VID_OPT_TEST:
                    command::buffer::add_text("vid_test\n");
                    break;
                case VID_OPT_APPLY:
                    command::buffer::add_text("vid_restart\n");
                    key_dest = key_game;
                    m_state = m_none;
                    IN_Activate();
                    break;
                default:
                    break;
            }
            break;

        default:
            break;
    }
}

/*
================
VID_MenuDraw
================
*/
static void VID_MenuDraw(void) {
    int i, y;
    qpic_t *p;
    const char *title;

    y = 4;

    // plaque
    p = Draw_CachePic("gfx/qplaque.lmp");
    M_DrawTransPic(16, y, p);

    //p = Draw_CachePic ("gfx/vidmodes.lmp");
    p = Draw_CachePic("gfx/p_option.lmp");
    M_DrawPic((320 - p->width) / 2, y, p);

    y += 28;

    // title
    title = "Video Options";
    M_PrintWhite((320 - 8 * strlen(title)) / 2, y, title);

    y += 16;

    // options
    for (i = 0; i < VIDEO_OPTIONS_ITEMS; i++) {
        switch (i) {
            case VID_OPT_MODE:
                M_Print(16, y, "        Video mode");
                M_Print(184, y, va("%ix%i", (int) vid_width.value, (int) vid_height.value));
                break;
            case VID_OPT_BPP:
                M_Print(16, y, "       Color depth");
                M_Print(184, y, va("%i", (int) vid_bpp.value));
                break;
            case VID_OPT_REFRESHRATE:
                M_Print(16, y, "      Refresh rate");
                M_Print(184, y, va("%i", (int) vid_refreshrate.value));
                break;
            case VID_OPT_FULLSCREEN:
                M_Print(16, y, "        Fullscreen");
                M_DrawCheckbox(184, y, (int) vid_fullscreen.value);
                break;
            case VID_OPT_VSYNC:
                M_Print(16, y, "     Vertical sync");
                if (gl_swap_control)
                    M_DrawCheckbox(184, y, (int) vid_vsync.value);
                else
                    M_Print(184, y, "N/A");
                break;
            case VID_OPT_TEST:
                y += 8; //separate the test and apply items
                M_Print(16, y, "      Test changes");
                break;
            case VID_OPT_APPLY:
                M_Print(16, y, "     Apply changes");
                break;
        }

        if (video_options_cursor == i)
            M_DrawCharacter(168, y, 12 + ((int) (realtime * 4) & 1));

        y += 8;
    }
}

/*
================
VID_Menu_f
================
*/
static void VID_Menu_f(void) {
    IN_Deactivate(modestate == MS_WINDOWED);
    key_dest = key_menu;
    m_state = m_video;
    m_entersound = true;

    //set all the cvars to match the current mode when entering the menu
    VID_SyncCvars();

    //set up bpp and rate lists based on current cvars
    VID_Menu_RebuildBppList();
    VID_Menu_RebuildRateList();
}
