quakeforge/libs/video/renderer/gl/vid_common_gl.c

/*
	vid_common_gl.c

	Common OpenGL video driver functions

	Copyright (C) 1996-1997 Id Software, Inc.
	Copyright (C) 2000      Marcus Sundberg [mackan@stacken.kth.se]

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#ifdef HAVE_MATH_H
# include <math.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif

#include "QF/cvar.h"
#include "QF/qargs.h"
#include "QF/quakefs.h"
#include "QF/sys.h"
#include "QF/va.h"
#include "QF/vid.h"
#include "QF/GL/defines.h"
#include "QF/GL/extensions.h"
#include "QF/GL/funcs.h"
#include "QF/GL/qf_rmain.h"
#include "QF/GL/qf_textures.h"
#include "QF/GL/qf_vid.h"

#include "compat.h"
#include "d_iface.h"
#include "r_internal.h"

#define WARP_WIDTH              320
#define WARP_HEIGHT             200

unsigned char	gl_15to8table[65536];

QF_glActiveTexture			qglActiveTexture = NULL;
QF_glMultiTexCoord2f		qglMultiTexCoord2f = NULL;
QF_glMultiTexCoord2fv		qglMultiTexCoord2fv = NULL;

const char		   *gl_extensions;
const char		   *gl_renderer;
const char		   *gl_vendor;
const char		   *gl_version;

int					gl_major;
int					gl_minor;
int					gl_release_number;

static int			gl_bgra_capable;
int					gl_use_bgra;
int					gl_va_capable;
static  int					driver_vaelements;
int					vaelements;
int					gl_filter_min = GL_LINEAR_MIPMAP_LINEAR;
int					gl_filter_max = GL_LINEAR;
float       		gldepthmin, gldepthmax;

// Multitexture
bool				gl_mtex_capable = false;
static int			gl_mtex_tmus = 0;
GLenum				gl_mtex_enum;
int					gl_mtex_active_tmus = 0;
bool				gl_mtex_fullbright = false;

// Combine
bool				gl_combine_capable = false;
int					lm_src_blend, lm_dest_blend;
float				gl_rgb_scale = 1.0;

QF_glColorTableEXT	qglColorTableEXT = NULL;

bool				gl_feature_mach64 = false;

// GL_EXT_texture_filter_anisotropic
bool 			gl_Anisotropy;
static float		aniso_max;
float				gl_aniso;

// GL_ATI_pn_triangles
static bool			TruForm;
static int			tess_max;
int			gl_tess;

// GL_LIGHT
int					gl_max_lights;

float gl_anisotropy;
static cvar_t gl_anisotropy_cvar = {
	.name = "gl_anisotropy",
	.description = 0,
	.default_value = "1.0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_float, .value = &gl_anisotropy },
};
int gl_fb_bmodels;
static cvar_t gl_fb_bmodels_cvar = {
	.name = "gl_fb_bmodels",
	.description =
		"Toggles fullbright color support for bmodels",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_fb_bmodels },
};
int gl_finish;
static cvar_t gl_finish_cvar = {
	.name = "gl_finish",
	.description =
		"wait for rendering to finish",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_finish },
};
int gl_max_size;
static cvar_t gl_max_size_cvar = {
	.name = "gl_max_size",
	.description =
		"Texture dimension",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_max_size },
};
int gl_multitexture;
static cvar_t gl_multitexture_cvar = {
	.name = "gl_multitexture",
	.description =
		"Use multitexture when available.",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_multitexture },
};
int gl_tessellate;
static cvar_t gl_tessellate_cvar = {
	.name = "gl_tessellate",
	.description = 0,
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_tessellate },
};
int gl_textures_bgra;
static cvar_t gl_textures_bgra_cvar = {
	.name = "gl_textures_bgra",
	.description =
		"If set to 1, try to use BGR & BGRA textures instead of RGB & RGBA.",
	.default_value = "0",
	.flags = CVAR_ROM,
	.value = { .type = &cexpr_int, .value = &gl_textures_bgra },
};
int gl_vaelements_max;
static cvar_t gl_vaelements_max_cvar = {
	.name = "gl_vaelements_max",
	.description =
		"Limit the vertex array size for buggy drivers. 0 (default) uses "
		"driver provided limit, -1 disables use of vertex arrays.",
	.default_value = "0",
	.flags = CVAR_ROM,
	.value = { .type = &cexpr_int, .value = &gl_vaelements_max },
};
int gl_vector_light;
static cvar_t gl_vector_light_cvar = {
	.name = "gl_vector_light",
	.description =
		"Enable use of GL vector lighting. 0 = flat lighting.",
	.default_value = "1",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_vector_light },
};
int gl_screenshot_byte_swap;
static cvar_t gl_screenshot_byte_swap_cvar = {
	.name = "gl_screenshot_byte_swap",
	.description =
		"Swap the bytes for gl screenshots. Needed if you get screenshots with"
		" red and blue swapped.",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_screenshot_byte_swap },
};

int gl_affinemodels;
static cvar_t gl_affinemodels_cvar = {
	.name = "gl_affinemodels",
	.description =
		"Makes texture rendering quality better if set to 1",
	.default_value = "0",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_affinemodels },
};
int gl_clear;
static cvar_t gl_clear_cvar = {
	.name = "gl_clear",
	.description =
		"Set to 1 to make background black. Useful for removing HOM effect",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_clear },
};
float gl_conspin;
static cvar_t gl_conspin_cvar = {
	.name = "gl_conspin",
	.description =
		"speed at which the console spins",
	.default_value = "0",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_float, .value = &gl_conspin },
};
int gl_constretch;
static cvar_t gl_constretch_cvar = {
	.name = "gl_constretch",
	.description =
		"toggle console between slide and stretch",
	.default_value = "0",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_constretch },
};
int gl_dlight_polyblend;
static cvar_t gl_dlight_polyblend_cvar = {
	.name = "gl_dlight_polyblend",
	.description =
		"Set to 1 to use a dynamic light effect faster on GL",
	.default_value = "0",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_dlight_polyblend },
};
int gl_dlight_smooth;
static cvar_t gl_dlight_smooth_cvar = {
	.name = "gl_dlight_smooth",
	.description =
		"Smooth dynamic vertex lighting",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_dlight_smooth },
};
int gl_fb_models;
static cvar_t gl_fb_models_cvar = {
	.name = "gl_fb_models",
	.description =
		"Toggles fullbright color support for models",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_fb_models },
};
int gl_keeptjunctions;
static cvar_t gl_keeptjunctions_cvar = {
	.name = "gl_keeptjunctions",
	.description =
		"Set to 0 to turn off colinear vertexes upon level load.",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_keeptjunctions },
};
int gl_lerp_anim;
static cvar_t gl_lerp_anim_cvar = {
	.name = "gl_lerp_anim",
	.description =
		"Toggles model animation interpolation",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_lerp_anim },
};
int gl_lightmap_align;
static cvar_t gl_lightmap_align_cvar = {
	.name = "gl_lightmap_align",
	.description =
		"Workaround for nvidia slow path. Set to 4 or 16 if you have an nvidia"
		" 3d accelerator, set to 1 otherwise.",
	.default_value = "1",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_lightmap_align },
};
int gl_lightmap_subimage;
static cvar_t gl_lightmap_subimage_cvar = {
	.name = "gl_lightmap_subimage",
	.description =
		"Lightmap Update method. Default 2 updates a minimum 'dirty rectangle'"
		" around the area changed. 1 updates every line that changed. 0 "
		"updates the entire lightmap.",
	.default_value = "1",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_lightmap_subimage },
};
int gl_nocolors;
static cvar_t gl_nocolors_cvar = {
	.name = "gl_nocolors",
	.description =
		"Set to 1, turns off all player colors",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_nocolors },
};
int gl_overbright;
static cvar_t gl_overbright_cvar = {
	.name = "gl_overbright",
	.description =
		"Darken lightmaps so that dynamic lights can be overbright. 1 = 0.75 "
		"brightness, 2 = 0.5 brightness.",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_overbright },
};
int gl_particle_mip;
static cvar_t gl_particle_mip_cvar = {
	.name = "gl_particle_mip",
	.description =
		"Toggles particle texture mipmapping.",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_particle_mip },
};
int gl_particle_size;
static cvar_t gl_particle_size_cvar = {
	.name = "gl_particle_size",
	.description =
		"Vertical and horizontal size of particle textures as a power of 2. "
		"Default is 5 (32 texel square).",
	.default_value = "5",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_particle_size },
};
int gl_picmip;
static cvar_t gl_picmip_cvar = {
	.name = "gl_picmip",
	.description =
		"Dimensions of textures. 0 is normal, 1 is half, 2 is 1/4",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_picmip },
};
int gl_playermip;
static cvar_t gl_playermip_cvar = {
	.name = "gl_playermip",
	.description =
		"Detail of player skins. 0 best, 4 worst.",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_playermip },
};
int gl_reporttjunctions;
static cvar_t gl_reporttjunctions_cvar = {
	.name = "gl_reporttjunctions",
	.description =
		"None",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_reporttjunctions },
};
int gl_sky_clip;
static cvar_t gl_sky_clip_cvar = {
	.name = "gl_sky_clip",
	.description =
		"controls amount of sky overdraw",
	.default_value = "2",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_sky_clip },
};
int gl_sky_debug;
static cvar_t gl_sky_debug_cvar = {
	.name = "gl_sky_debug",
	.description =
		"debugging `info' for sky clipping",
	.default_value = "0",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_sky_debug },
};
int gl_sky_divide;
static cvar_t gl_sky_divide_cvar = {
	.name = "gl_sky_divide",
	.description =
		"subdivide sky polys",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_sky_divide },
};
int gl_sky_multipass;
static cvar_t gl_sky_multipass_cvar = {
	.name = "gl_sky_multipass",
	.description =
		"controls whether the skydome is single or double pass",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_sky_multipass },
};
int gl_texsort;
static cvar_t gl_texsort_cvar = {
	.name = "gl_texsort",
	.description =
		"None",
	.default_value = "1",
	.flags = CVAR_NONE,
	.value = { .type = &cexpr_int, .value = &gl_texsort },
};
int gl_triplebuffer;
static cvar_t gl_triplebuffer_cvar = {
	.name = "gl_triplebuffer",
	.description =
		"Set to 1 by default. Fixes status bar flicker on some hardware",
	.default_value = "1",
	.flags = CVAR_ARCHIVE,
	.value = { .type = &cexpr_int, .value = &gl_triplebuffer },
};
static int vid_use8bit;
static cvar_t vid_use8bit_cvar = {
	.name = "vid_use8bit",
	.description =
		"Use 8-bit shared palettes.",
	.default_value = "0",
	.flags = CVAR_ROM,
	.value = { .type = &cexpr_int, .value = &vid_use8bit },
};

static void
gl_triplebuffer_f (void *data, const cvar_t *cvar)
{
	vid.numpages = gl_triplebuffer ? 3 : 2;
}

static void
gl_max_size_f (void *data, const cvar_t *cvar)
{
	GLint		texSize;

	if (!cvar)
		return;

	// Check driver's max texture size
	qfglGetIntegerv (GL_MAX_TEXTURE_SIZE, &texSize);
	if (gl_max_size < 1) {
		gl_max_size = texSize;
	} else {
		gl_max_size = bound (1, gl_max_size, texSize);
	}
}

static void
gl_textures_bgra_f (void *data, const cvar_t *cvar)
{
	if (!cvar)
		return;

	if (gl_textures_bgra && gl_bgra_capable) {
		gl_use_bgra = 1;
	} else {
		gl_use_bgra = 0;
	}
}

static void
gl_fb_bmodels_f (void *data, const cvar_t *cvar)
{
	if (!cvar)
		return;

	if (gl_fb_bmodels && gl_mtex_tmus >= 3) {
		gl_mtex_fullbright = true;
	} else {
		gl_mtex_fullbright = false;
	}
}

void
gl_multitexture_f (void *data, const cvar_t *cvar)
{
	if (gl_multitexture && gl_mtex_capable) {
		gl_mtex_active_tmus = gl_mtex_tmus;

		if (gl_fb_bmodels) {
			if (gl_fb_bmodels) {
				if (gl_mtex_tmus >= 3) {
					gl_mtex_fullbright = true;

					qglActiveTexture (gl_mtex_enum + 2);
					qfglEnable (GL_TEXTURE_2D);
					qfglTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,
								 GL_DECAL);
					qfglDisable (GL_TEXTURE_2D);
				} else {
					gl_mtex_fullbright = false;
					Sys_MaskPrintf (SYS_vid,
									"Not enough TMUs for BSP fullbrights.\n");
				}
			}
		} else {
			gl_mtex_fullbright = false;
		}

		// Lightmaps
		qglActiveTexture (gl_mtex_enum + 1);
		qfglEnable (GL_TEXTURE_2D);
		if (gl_overbright) {
			if (gl_combine_capable && gl_overbright) {
				qfglTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
				qfglTexEnvf (GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_MODULATE);
				qfglTexEnvf (GL_TEXTURE_ENV, GL_RGB_SCALE, gl_rgb_scale);
			} else {
				qfglTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
			}
		} else {
			qfglTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
		}
		qfglDisable (GL_TEXTURE_2D);

		// Base Texture
		qglActiveTexture (gl_mtex_enum + 0);
	} else {
		gl_mtex_active_tmus = 0;
		gl_mtex_fullbright = false;
	}
}

static void
gl_screenshot_byte_swap_f (void *data, const cvar_t *cvar)
{
	if (cvar)
		qfglPixelStorei (GL_PACK_SWAP_BYTES,
						 gl_screenshot_byte_swap ? GL_TRUE : GL_FALSE);
}

static void
gl_anisotropy_f (void *data, const cvar_t *var)
{
	if (gl_Anisotropy) {
		if (var)
			gl_aniso = (bound (1.0, gl_anisotropy, aniso_max));
		else
			gl_aniso = 1.0;
	} else {
		gl_aniso = 1.0;
		if (var)
			Sys_MaskPrintf (SYS_vid,
							"Anisotropy (GL_EXT_texture_filter_anisotropic) "
							"is not supported by your hardware and/or "
							"drivers.\n");
	}
}

static void
gl_tessellate_f (void *data, const cvar_t *var)
{
	if (TruForm) {
		if (var)
			gl_tess = (bound (0, gl_tessellate, tess_max));
		else
			gl_tess = 0;
		qfglPNTrianglesiATI (GL_PN_TRIANGLES_TESSELATION_LEVEL_ATI, gl_tess);
	} else {
		gl_tess = 0;
		if (var)
			Sys_MaskPrintf (SYS_vid,
							"TruForm (GL_ATI_pn_triangles) is not supported "
							"by your hardware and/or drivers.\n");
	}
}

static void
gl_vaelements_max_f (void *data, const cvar_t *cvar)
{
	if (gl_vaelements_max)
		vaelements = min (gl_vaelements_max, driver_vaelements);
	else
		vaelements = driver_vaelements;
}

static void
gl_sky_divide_f (void *data, const cvar_t *cvar)
{
	mod_sky_divide = gl_sky_divide;
}

static void
GL_Common_Init_Cvars (void)
{
	Cvar_Register (&vid_use8bit_cvar, 0, 0);
	Cvar_Register (&gl_textures_bgra_cvar, gl_textures_bgra_f, 0);
	Cvar_Register (&gl_fb_bmodels_cvar, gl_fb_bmodels_f, 0);
	Cvar_Register (&gl_finish_cvar, 0, 0);
	Cvar_Register (&gl_max_size_cvar, gl_max_size_f, 0);
	Cvar_Register (&gl_multitexture_cvar, gl_multitexture_f, 0);
	Cvar_Register (&gl_screenshot_byte_swap_cvar, gl_screenshot_byte_swap_f, 0);
	Cvar_Register (&gl_anisotropy_cvar, gl_anisotropy_f, 0);
	gl_anisotropy_cvar.description = nva (
		"Specifies degree of anisotropy, from 1.0 to %f. Higher anisotropy "
		"means less distortion of textures at shallow angles to the viewer.",
		aniso_max);
	Cvar_Register (&gl_tessellate_cvar, gl_tessellate_f, 0);
	gl_tessellate_cvar.description = nva (
		"Specifies tessellation level from 0 to %i. Higher tessellation level "
		"means more triangles.",
		tess_max);
	Cvar_Register (&gl_vaelements_max_cvar, gl_vaelements_max_f, 0);
	Cvar_Register (&gl_vector_light_cvar, 0, 0);
	Cvar_Register (&gl_affinemodels_cvar, 0, 0);
	Cvar_Register (&gl_clear_cvar, 0, 0);
	Cvar_Register (&gl_conspin_cvar, 0, 0);
	Cvar_Register (&gl_constretch_cvar, 0, 0);
	Cvar_Register (&gl_dlight_polyblend_cvar, 0, 0);
	Cvar_Register (&gl_dlight_smooth_cvar, 0, 0);
	Cvar_Register (&gl_fb_models_cvar, 0, 0);
	Cvar_Register (&gl_keeptjunctions_cvar, 0, 0);
	Cvar_Register (&gl_lerp_anim_cvar, 0, 0);

	Cvar_Register (&gl_lightmap_align_cvar, 0, 0);
	Cvar_Register (&gl_lightmap_subimage_cvar, 0, 0);
	Cvar_Register (&gl_nocolors_cvar, 0, 0);
	Cvar_Register (&gl_overbright_cvar, gl_overbright_f, 0);
	Cvar_Register (&gl_particle_mip_cvar, 0, 0);
	Cvar_Register (&gl_particle_size_cvar, 0, 0);
	Cvar_Register (&gl_picmip_cvar, 0, 0);
	Cvar_Register (&gl_playermip_cvar, 0, 0);
	Cvar_Register (&gl_reporttjunctions_cvar, 0, 0);
	Cvar_Register (&gl_sky_clip_cvar, 0, 0);
	Cvar_Register (&gl_sky_debug_cvar, 0, 0);
	Cvar_Register (&gl_sky_divide_cvar, gl_sky_divide_f, 0);
	Cvar_Register (&gl_sky_multipass_cvar, 0, 0);
	Cvar_Register (&gl_texsort_cvar, 0, 0);
	Cvar_Register (&gl_triplebuffer_cvar, gl_triplebuffer_f, 0);

	Cvar_AddListener (&gl_overbright_cvar, gl_multitexture_f, 0);
}

static void
CheckGLVersionString (void)
{
	gl_version = (char *) qfglGetString (GL_VERSION);
	if (sscanf (gl_version, "%d.%d", &gl_major, &gl_minor) == 2) {
		gl_release_number = 0;
		if (gl_major >= 1) {
			if (gl_minor >= 1) {
				gl_va_capable = true;
			} else {
				gl_va_capable = false;
			}
		}
	} else if (sscanf (gl_version, "%d.%d.%d", &gl_major, &gl_minor,
					   &gl_release_number) == 3) {
		if (gl_major >= 1) {
			if (gl_minor >= 1) {
				gl_va_capable = true;
			} else {
				gl_va_capable = false;
			}
		}
	} else {
		Sys_Error ("Malformed OpenGL version string!");
	}
	Sys_MaskPrintf (SYS_vid, "GL_VERSION: %s\n", gl_version);

	gl_vendor = (char *) qfglGetString (GL_VENDOR);
	Sys_MaskPrintf (SYS_vid, "GL_VENDOR: %s\n", gl_vendor);
	gl_renderer = (char *) qfglGetString (GL_RENDERER);
	Sys_MaskPrintf (SYS_vid, "GL_RENDERER: %s\n", gl_renderer);
	gl_extensions = (char *) qfglGetString (GL_EXTENSIONS);
	Sys_MaskPrintf (SYS_vid, "GL_EXTENSIONS: %s\n", gl_extensions);

	if (strstr (gl_renderer, "Mesa DRI Mach64"))
		gl_feature_mach64 = true;
}

static void
CheckAnisotropyExtensions (void)
{
	if (QFGL_ExtensionPresent ("GL_EXT_texture_filter_anisotropic")) {
		gl_Anisotropy = true;
		qfglGetFloatv (GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &aniso_max);
	} else {
		gl_Anisotropy = false;
		aniso_max = 1.0;
	}
}

static void
CheckBGRAExtensions (void)
{
	if (gl_major > 1 || (gl_major == 1 && gl_minor >= 3)) {
		gl_bgra_capable = true;
	} else if (QFGL_ExtensionPresent ("GL_EXT_bgra")) {
		gl_bgra_capable = true;
	} else {
		gl_bgra_capable = false;
	}
}

static void
CheckCombineExtensions (void)
{
	if (gl_major >= 1 && gl_minor >= 3) {
		gl_combine_capable = true;
		Sys_MaskPrintf (SYS_vid, "COMBINE active, multitextured doublebright "
						"enabled.\n");
	} else if (QFGL_ExtensionPresent ("GL_ARB_texture_env_combine")) {
		gl_combine_capable = true;
		Sys_MaskPrintf (SYS_vid, "COMBINE_ARB active, multitextured "
						"doublebright enabled.\n");
	} else {
		gl_combine_capable = false;
	}
}

/*
	CheckMultiTextureExtensions

	Check for ARB multitexture support
*/
static void
CheckMultiTextureExtensions (void)
{
	Sys_MaskPrintf (SYS_vid, "Checking for multitexture: ");
	if (COM_CheckParm ("-nomtex")) {
		Sys_MaskPrintf (SYS_vid, "disabled.\n");
		return;
	}
	if (gl_major >= 1 && gl_minor >= 3) {
		qfglGetIntegerv (GL_MAX_TEXTURE_UNITS, &gl_mtex_tmus);
		if (gl_mtex_tmus >= 2) {
			Sys_MaskPrintf (SYS_vid, "enabled, %d TMUs.\n", gl_mtex_tmus);
			qglMultiTexCoord2f =
				QFGL_ExtensionAddress ("glMultiTexCoord2f");
			qglMultiTexCoord2fv =
				QFGL_ExtensionAddress ("glMultiTexCoord2fv");
			qglActiveTexture = QFGL_ExtensionAddress ("glActiveTexture");
			gl_mtex_enum = GL_TEXTURE0;
			if (qglMultiTexCoord2f && gl_mtex_enum)
				gl_mtex_capable = true;
			else
				Sys_MaskPrintf (SYS_vid, "Multitexture disabled, could not "
								"find required functions\n");
		} else {
			Sys_MaskPrintf (SYS_vid,
							"Multitexture disabled, not enough TMUs.\n");
		}
	} else if (QFGL_ExtensionPresent ("GL_ARB_multitexture")) {
		qfglGetIntegerv (GL_MAX_TEXTURE_UNITS_ARB, &gl_mtex_tmus);
		if (gl_mtex_tmus >= 2) {
			Sys_MaskPrintf (SYS_vid, "enabled, %d TMUs.\n", gl_mtex_tmus);
			qglMultiTexCoord2f =
				QFGL_ExtensionAddress ("glMultiTexCoord2fARB");
			qglMultiTexCoord2fv =
				QFGL_ExtensionAddress ("glMultiTexCoord2fvARB");
			qglActiveTexture = QFGL_ExtensionAddress ("glActiveTextureARB");
			gl_mtex_enum = GL_TEXTURE0_ARB;
			if (qglMultiTexCoord2f && gl_mtex_enum)
				gl_mtex_capable = true;
			else
				Sys_MaskPrintf (SYS_vid, "Multitexture disabled, could not "
								"find required functions\n");
		} else {
			Sys_MaskPrintf (SYS_vid,
							"Multitexture disabled, not enough TMUs.\n");
		}
	} else {
		Sys_MaskPrintf (SYS_vid, "not found.\n");
	}
}

static void
CheckTruFormExtensions (void)
{
	if (QFGL_ExtensionPresent ("GL_ATI_pn_triangles")) {
		TruForm = true;
		qfglGetIntegerv (GL_MAX_PN_TRIANGLES_TESSELATION_LEVEL_ATI,
						 &tess_max);
		qfglPNTrianglesiATI (GL_PN_TRIANGLES_NORMAL_MODE_ATI,
							 GL_PN_TRIANGLES_NORMAL_MODE_QUADRATIC_ATI);
		qfglPNTrianglesiATI (GL_PN_TRIANGLES_POINT_MODE_ATI,
							 GL_PN_TRIANGLES_POINT_MODE_CUBIC_ATI);
	} else {
		TruForm = false;
		gl_tess = 0;
		tess_max = 0;
	}
}

static void
CheckVertexArraySize (void)
{
	qfglGetIntegerv (GL_MAX_ELEMENTS_VERTICES, &driver_vaelements);
	if (driver_vaelements > 65536)
		driver_vaelements = 65536;
	vaelements = driver_vaelements;
//	qfglGetIntegerv (MAX_ELEMENTS_INDICES, *vaindices);
}

static void
CheckLights (void)
{
	int		i;
	float	dark[4] = {0.0, 0.0, 0.0, 1.0},
			ambient[4] = {0.2, 0.2, 0.2, 1.0},
			diffuse[4] = {0.7, 0.7, 0.7, 1.0},
			specular[4] = {0.1, 0.1, 0.1, 1.0};

	qfglGetIntegerv (GL_MAX_LIGHTS, &gl_max_lights);
	Sys_MaskPrintf (SYS_vid, "Max GL Lights %d.\n", gl_max_lights);

	qfglEnable (GL_LIGHTING);
	qfglLightModelfv (GL_LIGHT_MODEL_AMBIENT, dark);
	qfglLightModelf (GL_LIGHT_MODEL_TWO_SIDE, 0.0);

	for (i = 0; i < gl_max_lights; i++) {
		qfglEnable (GL_LIGHT0 + i);
		qfglLightf (GL_LIGHT0 + i, GL_CONSTANT_ATTENUATION, 0.5);
		qfglDisable (GL_LIGHT0 + i);
	}

	// Set up material defaults
	qfglMaterialfv (GL_FRONT, GL_AMBIENT, ambient);
	qfglMaterialfv (GL_FRONT, GL_DIFFUSE, diffuse);
	qfglMaterialfv (GL_FRONT, GL_SPECULAR, specular);
	qfglMaterialf (GL_FRONT, GL_SHININESS, 1.0);

	qfglDisable (GL_LIGHTING);
}

static void
Tdfx_Init8bitPalette (void)
{
	// Check for 8bit Extensions and initialize them.
	int         i;

	if (vr_data.vid->is8bit)
		return;

	if (QFGL_ExtensionPresent ("3DFX_set_global_palette")) {
		char       *oldpal;
		GLubyte     table[256][4];
		QF_gl3DfxSetPaletteEXT qgl3DfxSetPaletteEXT = NULL;

		if (!(qgl3DfxSetPaletteEXT =
			  QFGL_ExtensionAddress ("gl3DfxSetPaletteEXT"))) {
			Sys_MaskPrintf (SYS_vid, "3DFX_set_global_palette not found.\n");
			return;
		}

		Sys_MaskPrintf (SYS_vid, "3DFX_set_global_palette.\n");

		oldpal = (char *) d_8to24table;	// d_8to24table3dfx;
		for (i = 0; i < 256; i++) {
			table[i][2] = *oldpal++;
			table[i][1] = *oldpal++;
			table[i][0] = *oldpal++;
			table[i][3] = 255;
			oldpal++;
		}
		qfglEnable (GL_SHARED_TEXTURE_PALETTE_EXT);
		qgl3DfxSetPaletteEXT ((GLuint *) table);
		vr_data.vid->is8bit = true;
	} else {
		Sys_MaskPrintf (SYS_vid, "\n    3DFX_set_global_palette not found.");
	}
}

/*
  The GL_EXT_shared_texture_palette seems like an idea which is
  /almost/ a good idea, but seems to be severely broken with many
  drivers, as such it is disabled.

  It should be noted, that a palette object extension as suggested by
  the GL_EXT_shared_texture_palette spec might be a very good idea in
  general.
*/
static void
Shared_Init8bitPalette (void)
{
	int 		i;
	GLubyte 	thePalette[256 * 3];
	GLubyte 	*oldPalette, *newPalette;

	if (vr_data.vid->is8bit)
		return;

	if (QFGL_ExtensionPresent ("GL_EXT_shared_texture_palette")) {
		if (!(qglColorTableEXT = QFGL_ExtensionAddress ("glColorTableEXT"))) {
			Sys_MaskPrintf (SYS_vid, "glColorTableEXT not found.\n");
			return;
		}

		Sys_MaskPrintf (SYS_vid, "GL_EXT_shared_texture_palette\n");

		qfglEnable (GL_SHARED_TEXTURE_PALETTE_EXT);
		oldPalette = (GLubyte *) d_8to24table;	// d_8to24table3dfx;
		newPalette = thePalette;
		for (i = 0; i < 256; i++) {
			*newPalette++ = *oldPalette++;
			*newPalette++ = *oldPalette++;
			*newPalette++ = *oldPalette++;
			oldPalette++;
		}
		qglColorTableEXT (GL_SHARED_TEXTURE_PALETTE_EXT, GL_RGB, 256, GL_RGB,
							GL_UNSIGNED_BYTE, (GLvoid *) thePalette);
		vr_data.vid->is8bit = true;
	} else {
		Sys_MaskPrintf (SYS_vid,
						"\n    GL_EXT_shared_texture_palette not found.");
	}
}

static void
VID_Init8bitPalette (void)
{
	Sys_MaskPrintf (SYS_vid, "Checking for 8-bit extension: ");
	if (vid_use8bit) {
		Tdfx_Init8bitPalette ();
		Shared_Init8bitPalette ();
		if (!vr_data.vid->is8bit)
			Sys_MaskPrintf (SYS_vid, "\n  8-bit extension not found.\n");
	} else {
		Sys_MaskPrintf (SYS_vid, "disabled.\n");
	}
}

void
GL_SetPalette (void *data, const byte *palette)
{
	const byte *pal;
	char        s[255];
	float       dist, bestdist;
	int			r1, g1, b1, k;
	unsigned int r, g, b, v;
	unsigned short i;
	unsigned int *table;
	static bool palflag = false;
	QFile      *f;
	static int  inited_8 = 0;

	if (!inited_8) {
		inited_8 = 1;
		// Check for 8-bit extension and initialize if present
		VID_Init8bitPalette ();
	}
	// 8 8 8 encoding
	Sys_MaskPrintf (SYS_vid, "Converting 8to24\n");

	pal = palette;
	table = d_8to24table;
	for (i = 0; i < 255; i++) { // used to be i<256, see d_8to24table below
		r = pal[0];
		g = pal[1];
		b = pal[2];
		pal += 3;

#ifdef WORDS_BIGENDIAN
		v = (255 << 0) + (r << 24) + (g << 16) + (b << 8);
#else
		v = (255 << 24) + (r << 0) + (g << 8) + (b << 16);
#endif
		*table++ = v;
	}
	d_8to24table[255] = 0;	// 255 is transparent

	// JACK: 3D distance calcs - k is last closest, l is the distance.
	if (palflag)
		return;
	palflag = true;

	f = QFS_FOpenFile ("glquake/15to8.pal");
	if (f) {
		Qread (f, gl_15to8table, 1 << 15);
		Qclose (f);
	} else {
		for (i = 0; i < (1 << 15); i++) {
			/* Maps
			   000000000000000
			   000000000011111 = Red  = 0x001F
			   000001111100000 = Blue = 0x03E0
			   111110000000000 = Grn  = 0x7C00
			*/
			r = ((i & 0x1F) << 3) + 4;
			g = ((i & 0x03E0) >> 2) + 4;
			b = ((i & 0x7C00) >> 7) + 4;

			pal = (unsigned char *) d_8to24table;

			for (v = 0, k = 0, bestdist = 10000.0; v < 256; v++, pal += 4) {
				r1 = (int) r - (int) pal[0];
				g1 = (int) g - (int) pal[1];
				b1 = (int) b - (int) pal[2];
				dist = sqrt (((r1 * r1) + (g1 * g1) + (b1 * b1)));
				if (dist < bestdist) {
					k = v;
					bestdist = dist;
				}
			}
			gl_15to8table[i] = k;
		}
		snprintf (s, sizeof (s), "%s/glquake/15to8.pal", qfs_gamedir->dir.def);
		if ((f = QFS_WOpen (s, 0)) != NULL) {
			Qwrite (f, gl_15to8table, 1 << 15);
			Qclose (f);
		}
	}
}

void
GL_Init_Common (void)
{
	GLF_FindFunctions ();
	CheckGLVersionString ();

	CheckAnisotropyExtensions ();
	CheckMultiTextureExtensions ();
	CheckCombineExtensions ();
	CheckBGRAExtensions ();
	CheckTruFormExtensions ();
	CheckVertexArraySize ();
	CheckLights ();

	GL_Common_Init_Cvars ();

	GL_TextureInit ();

	qfglClearColor (0, 0, 0, 0);

	qfglEnable (GL_TEXTURE_2D);
	qfglFrontFace (GL_CW);
	qfglCullFace (GL_BACK);
	qfglPolygonMode (GL_FRONT_AND_BACK, GL_FILL);
	qfglShadeModel (GL_FLAT);

	qfglEnable (GL_BLEND);
	qfglBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	qfglTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
	qfglTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, gl_filter_min);
	qfglTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gl_filter_max);
	if (gl_Anisotropy)
		qfglTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT,
						   gl_aniso);
	qfglTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	qfglTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
}