renderer: disable realtime lighting when ARB_texture_float isn't available

Author: illwieckz

src/engine/renderer/tr_image.cpp

@@ -2569,13 +2569,13 @@ static void R_CreateCurrentRenderImage()
 
 static void R_CreateDepthRenderImage()
 {
-	ASSERT( glConfig2.textureFloatAvailable );
-
 	if ( !glConfig2.realtimeLighting )
 	{
 		return;
 	}
 
+	ASSERT( glConfig2.textureFloatAvailable );
+
 	{
 		int width = glConfig.vidWidth;
 		int height = glConfig.vidHeight;

src/engine/renderer/tr_shade.cpp

@@ -52,6 +52,12 @@ static void EnableAvailableFeatures()
 			glConfig2.realtimeLighting = false;
 		}
 
+		if ( !glConfig2.textureFloatAvailable )
+		{
+			Log::Warn( "Tiled dynamic light renderer disabled because GL_ARB_texture_float is not available." );
+			glConfig2.realtimeLighting = false;
+		}
+
 		if ( glConfig2.max3DTextureSize == 0 )
 		{
 			Log::Warn( "Tiled dynamic light renderer disabled because of missing 3D texture support." );