From b2ab4b6cf1a38a66211cc72325cbc949986014c2 Mon Sep 17 00:00:00 2001
From: slipher <slipher@protonmail.com>
Date: Fri, 1 Aug 2025 17:25:45 -0500
Subject: [PATCH 1/2] Warn when loading non-2D shaders before map

Since the necessity of sRGB conversions is not known.
---
 src/engine/client/cl_main.cpp     | 2 +-
 src/engine/client/client.h        | 2 +-
 src/engine/renderer/tr_shader.cpp | 5 +++++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/engine/client/cl_main.cpp b/src/engine/client/cl_main.cpp
index da9a91d9d2..7a02046fe5 100644
--- a/src/engine/client/cl_main.cpp
+++ b/src/engine/client/cl_main.cpp
@@ -2143,7 +2143,7 @@ bool CL_InitRenderer()
 		FS_FCloseFile( f );
 	}
 
-	cls.whiteShader = re.RegisterShader( "white", RSF_NOMIP );
+	cls.whiteShader = re.RegisterShader( "white", RSF_NOMIP | RSF_2D );
 
 	g_console_field_width = cls.glconfig.vidWidth / SMALLCHAR_WIDTH - 2;
 	g_consoleField.SetWidth(g_console_field_width);
diff --git a/src/engine/client/client.h b/src/engine/client/client.h
index f53156e89f..6e2eb49000 100644
--- a/src/engine/client/client.h
+++ b/src/engine/client/client.h
@@ -315,7 +315,7 @@ struct clientStatic_t
 	glconfig_t  glconfig;
 	glconfig2_t glconfig2;
 	qhandle_t   charSetShader;
-	qhandle_t   whiteShader;
+	qhandle_t   whiteShader; // used for console drawing
 	bool    useLegacyConsoleFont;
 	bool    useLegacyConsoleFace;
 	fontInfo_t *consoleFont;
diff --git a/src/engine/renderer/tr_shader.cpp b/src/engine/renderer/tr_shader.cpp
index c59bb64b89..3ec2926424 100644
--- a/src/engine/renderer/tr_shader.cpp
+++ b/src/engine/renderer/tr_shader.cpp
@@ -6092,6 +6092,11 @@ shader_t       *R_FindShader( const char *name, int flags )
 	// going to have to upload an image
 	R_SyncRenderThread();
 
+	if ( !( flags & RSF_2D ) && !tr.worldMapLoaded )
+	{
+		Log::Warn( "non-2D shader '%s' registered before map colorspace is known, assuming naive blending", name );
+	}
+
 	ClearGlobalShader();
 
 	Q_strncpyz( shader.name, strippedName, sizeof( shader.name ) );

From 3493cb6139275a7b00791b64f875965fde6c3dc6 Mon Sep 17 00:00:00 2001
From: slipher <slipher@protonmail.com>
Date: Fri, 1 Aug 2025 18:16:44 -0500
Subject: [PATCH 2/2] Implement stage-level colorspace shader keyword

Allows making conditional stages that depend on whether naive or linear
blending is used.
---
 src/engine/renderer/tr_shader.cpp | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/engine/renderer/tr_shader.cpp b/src/engine/renderer/tr_shader.cpp
index 3ec2926424..5ef5fb2891 100644
--- a/src/engine/renderer/tr_shader.cpp
+++ b/src/engine/renderer/tr_shader.cpp
@@ -2020,6 +2020,7 @@ static bool ParseStage( shaderStage_t *stage, const char **text )
 	filterType_t filterType;
 	char         buffer[ 1024 ] = "";
 	bool     loadMap = false;
+	bool colorspaceMatch = true;
 
 	while ( true )
 	{
@@ -2855,6 +2856,23 @@ static bool ParseStage( shaderStage_t *stage, const char **text )
 				continue;
 			}
 		}
+		// disable the stage if the renderer's blending mode does not match the specified mode
+		else if ( !Q_stricmp( token, "colorspace" ) )
+		{
+			token = COM_ParseExt2( text, false );
+			if ( !Q_stricmp( token, "naive" ) )
+			{
+				colorspaceMatch = !tr.worldLinearizeTexture;
+			}
+			else if ( !Q_stricmp( token, "linear" ) )
+			{
+				colorspaceMatch = tr.worldLinearizeTexture;
+			}
+			else
+			{
+				Log::Warn( "unknown colorspace '%s' in shader '%s'", token, shader.name );
+			}
+		}
 		// alpha <arithmetic expression>
 		else if ( !Q_stricmp( token, "alpha" ) )
 		{
@@ -3233,6 +3251,11 @@ static bool ParseStage( shaderStage_t *stage, const char **text )
 		}
 	}
 
+	if ( !colorspaceMatch )
+	{
+		return true; // parsing succeeded, but not active
+	}
+
 	// parsing succeeded
 	stage->active = true;
 
@@ -3866,8 +3889,6 @@ static bool ParseShader( const char *_text )
 				return false;
 			}
 
-			stage->active = true;
-
 			/* Examples of shaders with light styles, those
 			shaders are generated by the q3map2 map compiler.