Clean up some OpenGL feature detection cruft

src/engine/renderer/tr_image.cpp

@@ -919,18 +919,6 @@ void R_UploadImage( const char *name, const byte **dataArray, int numLayers, int
 		format = GL_DEPTH_STENCIL;
 		internalFormat = GL_DEPTH24_STENCIL8;
 	}
-	else if ( image->bits & IF_RGBA16 )
-	{
-		if ( !glConfig2.textureRGBA16BlendAvailable )
-		{
-			Log::Warn("RGBA16 image '%s' cannot be blended", image->name );
-			internalFormat = GL_RGBA8;
-		}
-		else
-		{
-			internalFormat = GL_RGBA16;
-		}
-	}
 	else if ( image->bits & ( IF_RGBA16F | IF_RGBA32F | IF_TWOCOMP16F | IF_TWOCOMP32F | IF_ONECOMP16F | IF_ONECOMP32F ) )
 	{
 		if( !glConfig2.textureFloatAvailable ) {

src/engine/renderer/tr_init.cpp

@@ -968,10 +968,8 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 			Log::Notice("Using OpenGL version %d.%d, requested: %d.%d", glConfig2.glMajor, glConfig2.glMinor, glConfig2.glRequestedMajor, glConfig2.glRequestedMinor );
 		}
 
-		if ( glConfig.driverType == glDriverType_t::GLDRV_OPENGL3 )
+		if ( std::make_pair( glConfig2.glMajor, glConfig2.glMinor ) >= std::make_pair( 3, 2 ) )
 		{
-			Log::Notice("%sUsing OpenGL 3.x context.", Color::ToString( Color::Green ) );
-
 			/* See https://www.khronos.org/opengl/wiki/OpenGL_Context
 			for information about core, compatibility and forward context. */
 
@@ -983,19 +981,15 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 			{
 				Log::Notice("%sUsing an OpenGL compatibility profile.", Color::ToString( Color::Red ) );
 			}
+		}
 
-			if ( glConfig2.glForwardCompatibleContext )
-			{
-				Log::Notice("OpenGL 3.x context is forward compatible.");
-			}
-			else
-			{
-				Log::Notice("OpenGL 3.x context is not forward compatible.");
-			}
+		if ( glConfig2.glForwardCompatibleContext )
+		{
+			Log::Notice("OpenGL context is forward compatible.");
 		}
 		else
 		{
-			Log::Notice("%sUsing OpenGL 2.x context.", Color::ToString( Color::Red ) );
+			Log::Notice("OpenGL context is not forward compatible.");
 		}
 
 		if ( glConfig2.glEnabledExtensionsString.length() != 0 )
@@ -1047,20 +1041,6 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 			Log::Notice("%sMissing GPU vertex skinning, models are not hardware-accelerated.", Color::ToString( Color::Red ) );
 		}
 
-		switch ( glConfig2.textureRGBA16BlendAvailable )
-		{
-			case 1:
-				Log::Notice( "%sUsing GL_RGBA16 with GL_FRAMEBUFFER_BLEND.", Color::ToString( Color::Green ) );
-				break;
-			case -1:
-				Log::Notice( "%sUsing GL_RGBA16 with GL_FRAMEBUFFER_BLEND (assumed to be available).", Color::ToString( Color::Yellow ) );
-				break;
-			default:
-			case 0:
-				Log::Notice( "%sMissing GL_RGBA16 with GL_FRAMEBUFFER_BLEND.", Color::ToString( Color::Red ) );
-				break;
-		}
-
 		if ( glConfig.smpActive )
 		{
 			Log::Notice("Using dual processor acceleration." );

src/engine/renderer/tr_local.h

@@ -473,7 +473,6 @@ enum class ssaoMode {
 	  IF_DEPTH32 = BIT( 11 ),
 	  IF_PACKED_DEPTH24_STENCIL8 = BIT( 12 ),
 	  IF_LIGHTMAP = BIT( 13 ),
-	  IF_RGBA16 = BIT( 14 ),
 	  IF_RGBE = BIT( 15 ),
 	  IF_ALPHATEST = BIT( 16 ), // FIXME: this is unused
 	  IF_ALPHA = BIT( 17 ),

src/engine/renderer/tr_public.h

@@ -87,10 +87,8 @@ struct glconfig2_t
 	int maxTexIndirections;
 
 	bool drawBuffersAvailable;
-	bool internalFormatQuery2Available;
 	bool textureHalfFloatAvailable;
 	bool textureFloatAvailable;
-	int textureRGBA16BlendAvailable;
 	bool textureIntegerAvailable;
 	bool textureRGAvailable;
 	bool computeShaderAvailable;

src/engine/renderer/tr_types.h

@@ -251,20 +251,13 @@ enum class textureCompression_t
   TC_EXT_COMP_S3TC
 };
 
-// Keep the list in sdl_glimp.c:reportDriverType in sync with this
+// TODO(0.56): remove.
 enum class glDriverType_t
 {
   GLDRV_UNKNOWN = -1,
-  GLDRV_ICD, // driver is integrated with window system
-  // WARNING: there are tests that check for
-  // > GLDRV_ICD for minidriverness, so this
-  // should always be the lowest value in this
-  // enum set
-  GLDRV_STANDALONE, // driver is a non-3Dfx standalone driver
-
-// XreaL BEGIN
-  GLDRV_OPENGL3, // new driver system
-// XreaL END
+  GLDRV_ICD,
+  GLDRV_STANDALONE,
+  GLDRV_OPENGL3,
 };
 
 // Keep the list in sdl_glimp.c:reportHardwareType in sync with this

src/engine/sys/sdl_glimp.cpp

@@ -46,8 +46,6 @@ static Cvar::Modified<Cvar::Cvar<bool>> r_noBorder(
 static Cvar::Modified<Cvar::Range<Cvar::Cvar<int>>> r_swapInterval(
 	"r_swapInterval", "enable vsync on every Nth frame, negative for apdative", Cvar::ARCHIVE, 0, -5, 5 );
 
-static Cvar::Cvar<std::string> r_glForceDriver(
-	"r_glForceDriver", "treat the OpenGL driver type as: 'icd' 'standalone' or 'opengl3'", Cvar::NONE, "");
 static Cvar::Cvar<std::string> r_glForceHardware(
 	"r_glForceHardware", "treat the GPU type as: 'r300' or 'generic'", Cvar::NONE, "");
 
@@ -135,10 +133,6 @@ static Cvar::Cvar<bool> workaround_glDriver_amd_oglp_disableBindlessTexture(
 	"workaround.glDriver.amd.oglp.disableBindlessTexture",
 	"Disable ARB_bindless_texture on AMD OGLP driver",
 	Cvar::NONE, true );
-static Cvar::Cvar<bool> workaround_glDriver_mesa_ati_rv300_disableRgba16Blend(
-	"workaround.glDriver.mesa.ati.rv300.disableRgba16Blend",
-	"Disable misdetected RGBA16 on Mesa driver on RV300 hardware",
-	Cvar::NONE, true );
 static Cvar::Cvar<bool> workaround_glDriver_mesa_ati_rv300_useFloatVertex(
 	"workaround.glDriver.mesa.ati.rv300.useFloatVertex",
 	"Use float vertex instead of supported-but-slower half-float vertex on Mesa driver on ATI RV300 hardware",
@@ -1381,7 +1375,19 @@ static void GLimp_RegisterConfiguration( const glConfiguration& highestConfigura
 		}
 	}
 
-	if ( requestedConfiguration.profile == glProfile::CORE )
+	{
+		int GLmajor, GLminor;
+		if ( 2 != sscanf( ( const char * ) glGetString( GL_VERSION ), "%d.%d", &GLmajor, &GLminor ) )
+		{
+			Sys::Error( "Indecipherable GL_VERSION" );
+		}
+
+		glConfig2.glMajor = GLmajor;
+		glConfig2.glMinor = GLminor;
+	}
+
+	// CONTEXT_FLAGS and forward compatibility were added in OpenGL 3.0
+	if ( glConfig2.glMajor >= 3 )
 	{
 		// Check if context is forward compatible.
 		int contextFlags;
@@ -1391,26 +1397,18 @@ static void GLimp_RegisterConfiguration( const glConfiguration& highestConfigura
 
 		if ( glConfig2.glForwardCompatibleContext )
 		{
-			logger.Debug( "Provided OpenGL core context is forward compatible." );
+			logger.Debug( "Provided OpenGL context is forward compatible." );
 		}
 		else
 		{
-			logger.Debug( "Provided OpenGL core context is not forward compatible." );
+			logger.Debug( "Provided OpenGL context is not forward compatible." );
 		}
 	}
 	else
 	{
 		glConfig2.glForwardCompatibleContext = false;
 	}
 
-	{
-		int GLmajor, GLminor;
-		sscanf( ( const char * ) glGetString( GL_VERSION ), "%d.%d", &GLmajor, &GLminor );
-
-		glConfig2.glMajor = GLmajor;
-		glConfig2.glMinor = GLminor;
-	}
-
 	// Get our config strings.
 	Q_strncpyz( glConfig.vendor_string, ( char * ) glGetString( GL_VENDOR ), sizeof( glConfig.vendor_string ) );
 	Q_strncpyz( glConfig.renderer_string, ( char * ) glGetString( GL_RENDERER ), sizeof( glConfig.renderer_string ) );
@@ -1467,17 +1465,6 @@ static rserr_t GLimp_CheckOpenGLVersion( const glConfiguration &requestedConfigu
 		return rserr_t::RSERR_OLD_GL;
 	}
 
-	if ( glConfig2.glMajor < 3 || ( glConfig2.glMajor == 3 && glConfig2.glMinor < 2 ) )
-	{
-		// Shaders are supported, but not all OpenGL 3.x features
-		logger.Notice("Using GL3 Renderer in OpenGL 2.x mode..." );
-	}
-	else
-	{
-		logger.Notice("Using GL3 Renderer in OpenGL 3.x mode..." );
-		glConfig.driverType = glDriverType_t::GLDRV_OPENGL3;
-	}
-
 	return rserr_t::RSERR_OK;
 }
 
@@ -2108,75 +2095,6 @@ static void GLimp_InitExtensions()
 	// made required in OpenGL 3.0
 	glConfig2.textureFloatAvailable = LOAD_EXTENSION_WITH_TEST( ExtFlag_CORE, ARB_texture_float, r_ext_texture_float.Get() );
 
-	glConfig2.internalFormatQuery2Available = LOAD_EXTENSION_WITH_TEST( ExtFlag_NONE, ARB_internalformat_query2, r_arb_internalformat_query2.Get() );
-
-	if ( glConfig2.internalFormatQuery2Available )
-	{
-		GLint64 param;
-		glGetInternalformati64v( GL_TEXTURE_2D, GL_RGBA16, GL_FRAMEBUFFER_BLEND, 1, &param );
-
-		if ( param == GL_FULL_SUPPORT || param == GL_TRUE )
-		{
-			/* There is a discrepancy between OpenGL specification and OpenGL reference pages.
-
-			The OpenGL 4.3 Core specification says the query should return either GL_FULL_SUPPORT,
-			GL_CAVEAT_SUPPORT, or GL_NONE:
-
-			- https://registry.khronos.org/OpenGL/specs/gl/glspec43.core.pdf#page=517
-
-			The ARB_internalformat_query2 document says the same:
-
-			- https://registry.khronos.org/OpenGL/extensions/ARB/ARB_internalformat_query2.txt
-
-			The OpenGL wiki page for glGetInternalformat says the same:
-
-			- https://www.khronos.org/opengl/wiki/GLAPI/glGetInternalformat
-
-			But the glGetInternalformat reference page says the query should return GL_TRUE
-			or GL_FALSE:
-
-			- https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGetInternalformat.xhtml
-
-			The meaning of GL_CAVEAT_SUPPORT as a return of a GL_FRAMEBUFFER_BLEND query is
-			unknown. See this thread for details:
-
-			- https://github.com/KhronosGroup/OpenGL-Refpages/issues/157
-
-			Because of this discrepancy in documentation, drivers may have implemented
-			either GL_FULL_SUPPORT or GL_TRUE as a return for feature availability. */
-			glConfig2.textureRGBA16BlendAvailable = 1;
-		}
-		else if ( param == GL_CAVEAT_SUPPORT || param == GL_NONE )
-		{
-			/* Older Mesa versions were mistakenly reporting full support for every driver on
-			every hardware. A return that is not GL_FULL_SUPPORT and not GL_TRUE is the only
-			value we can trust. See those threads for details:
-
-			- https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30612
-			- https://gitlab.freedesktop.org/mesa/mesa/-/issues/11669#note_2521403
-
-			GL_FALSE has same value as GL_NONE. */
-			glConfig2.textureRGBA16BlendAvailable = 0;
-		}
-	}
-	else
-	{
-		/* Assume this is an old driver without the query extension but the RGBA16 blending is
-		available, as the feature is much older than the extension to check for it, the feature
-		is very likely supported. */
-		glConfig2.textureRGBA16BlendAvailable = -1;
-	}
-
-	/* Workaround for drivers not implementing the feature query or wrongly reporting the feature
-	to be supported, for various reasons. */
-	if ( workaround_glDriver_mesa_ati_rv300_disableRgba16Blend.Get() )
-	{
-		if ( glConfig2.textureRGBA16BlendAvailable != 0 && glConfig.hardwareType == glHardwareType_t::GLHW_R300 )
-		{
-			glConfig2.textureRGBA16BlendAvailable = 0;
-		}
-	}
-
 	bool gpuShader4Enabled = r_ext_gpu_shader4.Get();
 
 	if ( gpuShader4Enabled
@@ -2663,19 +2581,6 @@ static const int R_MODE_FALLBACK = 3; // 640 * 480
 
 /* Support code for GLimp_Init */
 
-static void reportDriverType( bool force )
-{
-	static const char *const drivers[] = {
-		"integrated", "stand-alone", "OpenGL 3+", "Mesa"
-	};
-	if (glConfig.driverType > glDriverType_t::GLDRV_UNKNOWN && (unsigned) glConfig.driverType < ARRAY_LEN( drivers ) )
-	{
-		logger.Notice("%s graphics driver class '%s'",
-		           force ? "User has forced" : "Detected",
-		           drivers[Util::ordinal(glConfig.driverType)] );
-	}
-}
-
 static void reportHardwareType( bool force )
 {
 	static const char *const hardware[] = {
@@ -2699,7 +2604,7 @@ of OpenGL
 */
 bool GLimp_Init()
 {
-	glConfig.driverType = glDriverType_t::GLDRV_ICD;
+	glConfig.driverType = glDriverType_t::GLDRV_OPENGL3;
 
 	r_sdlDriver = Cvar_Get( "r_sdlDriver", "", CVAR_ROM );
 	r_allowResize = Cvar_Get( "r_allowResize", "0", CVAR_LATCH );
@@ -2708,7 +2613,6 @@ bool GLimp_Init()
 
 	Cvar::Latch( workaround_glDriver_amd_adrenalin_disableBindlessTexture );
 	Cvar::Latch( workaround_glDriver_amd_oglp_disableBindlessTexture );
-	Cvar::Latch( workaround_glDriver_mesa_ati_rv300_disableRgba16Blend );
 	Cvar::Latch( workaround_glDriver_mesa_ati_rv300_useFloatVertex );
 	Cvar::Latch( workaround_glDriver_mesa_ati_rv600_disableHyperZ );
 	Cvar::Latch( workaround_glDriver_mesa_broadcom_vc4_useFloatVertex );
@@ -2828,10 +2732,11 @@ bool GLimp_Init()
 
 	glConfig2.glExtensionsString = std::string();
 
-	if ( glConfig.driverType == glDriverType_t::GLDRV_OPENGL3 )
+	if ( glConfig2.glMajor >= 3 )
 	{
 		GLint numExts, i;
 
+		// NUM_EXTENSIONS and glGetStringi( GL_EXTENSIONS, i ) were added in OpenGL 3.0
 		glGetIntegerv( GL_NUM_EXTENSIONS, &numExts );
 
 		logger.Debug( "Found %d OpenGL extensions.", numExts );
@@ -2869,6 +2774,7 @@ bool GLimp_Init()
 	}
 	else
 	{
+		// glGetString( GL_EXTENSIONS ) was deprecated in OpenGL 3.0
 		char* extensions_string = ( char * ) glGetString( GL_EXTENSIONS );
 
 		if ( extensions_string == nullptr )
@@ -2889,34 +2795,18 @@ bool GLimp_Init()
 		}
 	}
 
-	if ( glConfig2.hardwareVendor == glHardwareVendor_t::ATI
-		&& glConfig.driverType != glDriverType_t::GLDRV_OPENGL3 )
+	if ( glConfig2.hardwareVendor == glHardwareVendor_t::ATI &&
+	     std::make_pair( glConfig2.glMajor, glConfig2.glMinor ) < std::make_pair( 3, 2 ) )
 	{
 		glConfig.hardwareType = glHardwareType_t::GLHW_R300;
 	}
 
-	reportDriverType( false );
 	reportHardwareType( false );
 
 	{ // allow overriding where the user really does know better
-		Cvar::Latch( r_glForceDriver );
 		Cvar::Latch( r_glForceHardware );
-		glDriverType_t   driverType   = glDriverType_t::GLDRV_UNKNOWN;
 		glHardwareType_t hardwareType = glHardwareType_t::GLHW_UNKNOWN;
 
-		if      ( Str::IsIEqual( r_glForceDriver.Get(), "icd" ) )
-		{
-			driverType = glDriverType_t::GLDRV_ICD;
-		}
-		else if ( Str::IsIEqual( r_glForceDriver.Get(), "standalone" ) )
-		{
-			driverType = glDriverType_t::GLDRV_STANDALONE;
-		}
-		else if ( Str::IsIEqual( r_glForceDriver.Get(), "opengl3" ) )
-		{
-			driverType = glDriverType_t::GLDRV_OPENGL3;
-		}
-
 		if      ( Str::IsIEqual( r_glForceHardware.Get(), "generic" ) )
 		{
 			hardwareType = glHardwareType_t::GLHW_GENERIC;
@@ -2926,12 +2816,6 @@ bool GLimp_Init()
 			hardwareType = glHardwareType_t::GLHW_R300;
 		}
 
-		if ( driverType != glDriverType_t::GLDRV_UNKNOWN )
-		{
-			glConfig.driverType = driverType;
-			reportDriverType( true );
-		}
-
 		if ( hardwareType != glHardwareType_t::GLHW_UNKNOWN )
 		{
 			glConfig.hardwareType = hardwareType;