From 552953540cbb8065160c6670e8655b8d4279c286 Mon Sep 17 00:00:00 2001
From: icculus <icculus@edf5b092-35ff-0310-97b2-ce42778d08ea>
Date: Fri, 13 Jun 2008 02:28:51 +0000
Subject: Added GL_EXT_texture_compression_s3tc support.

GL_S3_s3tc, which Quake 3 previously supported, is legacy. This new codepath
 is the common, vendor-neutral extension to get the same results.


git-svn-id: svn://svn.icculus.org/quake3/trunk@1387 edf5b092-35ff-0310-97b2-ce42778d08ea
---
 code/renderer/tr_image.c |  7 +++++-
 code/renderer/tr_types.h |  3 ++-
 code/sdl/sdl_glimp.c     | 58 ++++++++++++++++++++++++++++++++++++++----------
 3 files changed, 54 insertions(+), 14 deletions(-)

(limited to 'code')

diff --git a/code/renderer/tr_image.c b/code/renderer/tr_image.c
index 737370f..c3828cd 100644
--- a/code/renderer/tr_image.c
+++ b/code/renderer/tr_image.c
@@ -182,6 +182,7 @@ void R_ImageList_f( void ) {
 			ri.Printf( PRINT_ALL, "RGB8" );
 			break;
 		case GL_RGB4_S3TC:
+		case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 			ri.Printf( PRINT_ALL, "S3TC " );
 			break;
 		case GL_RGBA4:
@@ -602,7 +603,11 @@ static void Upload32( unsigned *data,
 			}
 			else
 			{
-				if ( glConfig.textureCompression == TC_S3TC )
+				if ( glConfig.textureCompression == TC_S3TC_ARB )
+				{
+					internalFormat = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
+				}
+				else if ( glConfig.textureCompression == TC_S3TC )
 				{
 					internalFormat = GL_RGB4_S3TC;
 				}
diff --git a/code/renderer/tr_types.h b/code/renderer/tr_types.h
index 2a10342..50f9759 100644
--- a/code/renderer/tr_types.h
+++ b/code/renderer/tr_types.h
@@ -151,7 +151,8 @@ typedef enum {
 */
 typedef enum {
 	TC_NONE,
-	TC_S3TC
+	TC_S3TC,  // this is for the GL_S3_s3tc extension.
+	TC_S3TC_ARB  // this is for the GL_EXT_texture_compression_s3tc extension.
 } textureCompression_t;
 
 typedef enum {
diff --git a/code/sdl/sdl_glimp.c b/code/sdl/sdl_glimp.c
index c378d5d..f6719a5 100644
--- a/code/sdl/sdl_glimp.c
+++ b/code/sdl/sdl_glimp.c
@@ -445,6 +445,17 @@ static qboolean GLimp_StartDriverAndSetMode( int mode, qboolean fullscreen )
 
 	return qtrue;
 }
+
+static qboolean GLimp_HaveExtension(const char *ext)
+{
+	const char *ptr = Q_stristr( glConfig.extensions_string, ext );
+	if (ptr == NULL)
+		return qfalse;
+	ptr += strlen(ext);
+	return ((*ptr == ' ') || (*ptr == '\0'));  // verify it's complete string.
+}
+
+
 /*
 ===============
 GLimp_InitExtensions
@@ -460,29 +471,52 @@ static void GLimp_InitExtensions( void )
 
 	ri.Printf( PRINT_ALL, "Initializing OpenGL extensions\n" );
 
-	// GL_S3_s3tc
-	if ( Q_stristr( glConfig.extensions_string, "GL_S3_s3tc" ) )
+	glConfig.textureCompression = TC_NONE;
+
+	// GL_EXT_texture_compression_s3tc
+	if ( GLimp_HaveExtension( "GL_ARB_texture_compression" ) &&
+	     GLimp_HaveExtension( "GL_EXT_texture_compression_s3tc" ) )
 	{
 		if ( r_ext_compressed_textures->value )
 		{
-			glConfig.textureCompression = TC_S3TC;
-			ri.Printf( PRINT_ALL, "...using GL_S3_s3tc\n" );
+			glConfig.textureCompression = TC_S3TC_ARB;
+			ri.Printf( PRINT_ALL, "...using GL_EXT_texture_compression_s3tc\n" );
 		}
 		else
 		{
-			glConfig.textureCompression = TC_NONE;
-			ri.Printf( PRINT_ALL, "...ignoring GL_S3_s3tc\n" );
+			ri.Printf( PRINT_ALL, "...ignoring GL_EXT_texture_compression_s3tc\n" );
 		}
 	}
 	else
 	{
-		glConfig.textureCompression = TC_NONE;
-		ri.Printf( PRINT_ALL, "...GL_S3_s3tc not found\n" );
+		ri.Printf( PRINT_ALL, "...GL_EXT_texture_compression_s3tc not found\n" );
 	}
 
+	// GL_S3_s3tc ... legacy extension before GL_EXT_texture_compression_s3tc.
+	if (glConfig.textureCompression == TC_NONE)
+	{
+		if ( GLimp_HaveExtension( "GL_S3_s3tc" ) )
+		{
+			if ( r_ext_compressed_textures->value )
+			{
+				glConfig.textureCompression = TC_S3TC;
+				ri.Printf( PRINT_ALL, "...using GL_S3_s3tc\n" );
+			}
+			else
+			{
+				ri.Printf( PRINT_ALL, "...ignoring GL_S3_s3tc\n" );
+			}
+		}
+		else
+		{
+			ri.Printf( PRINT_ALL, "...GL_S3_s3tc not found\n" );
+		}
+	}
+
+
 	// GL_EXT_texture_env_add
 	glConfig.textureEnvAddAvailable = qfalse;
-	if ( Q_stristr( glConfig.extensions_string, "EXT_texture_env_add" ) )
+	if ( GLimp_HaveExtension( "EXT_texture_env_add" ) )
 	{
 		if ( r_ext_texture_env_add->integer )
 		{
@@ -504,7 +538,7 @@ static void GLimp_InitExtensions( void )
 	qglMultiTexCoord2fARB = NULL;
 	qglActiveTextureARB = NULL;
 	qglClientActiveTextureARB = NULL;
-	if ( Q_stristr( glConfig.extensions_string, "GL_ARB_multitexture" ) )
+	if ( GLimp_HaveExtension( "GL_ARB_multitexture" ) )
 	{
 		if ( r_ext_multitexture->value )
 		{
@@ -541,7 +575,7 @@ static void GLimp_InitExtensions( void )
 	}
 
 	// GL_EXT_compiled_vertex_array
-	if ( Q_stristr( glConfig.extensions_string, "GL_EXT_compiled_vertex_array" ) )
+	if ( GLimp_HaveExtension( "GL_EXT_compiled_vertex_array" ) )
 	{
 		if ( r_ext_compiled_vertex_array->value )
 		{
@@ -564,7 +598,7 @@ static void GLimp_InitExtensions( void )
 	}
 
 	textureFilterAnisotropic = qfalse;
-	if ( strstr( glConfig.extensions_string, "GL_EXT_texture_filter_anisotropic" ) )
+	if ( GLimp_HaveExtension( "GL_EXT_texture_filter_anisotropic" ) )
 	{
 		if ( r_ext_texture_filter_anisotropic->integer ) {
 			qglGetIntegerv( GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, (GLint *)&maxAnisotropy );
-- 
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