From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 1 Feb 2021 12:52:05 +0000 (+0200)
Subject: Always use swizzle to implement luminance formats
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=2ed67ce59027c34f0ae78118d82c70eb1577e949

Always use swizzle to implement luminance formats

ARB_texture_swizzle was promoted to core in OpenGL 3.3 and hardware not
supporting that is obsolete.
---

diff --git a/source/texture.cpp b/source/texture.cpp
index 90e3bb17..772f2d16 100644
--- a/source/texture.cpp
+++ b/source/texture.cpp
@@ -53,26 +53,28 @@ DataType Texture::get_alloc_type(PixelFormat fmt)
 
 void Texture::set_internal_format(PixelFormat fmt)
 {
-	swizzle = NO_SWIZZLE;
-	if(ARB_texture_rg && ARB_texture_swizzle)
+	FormatSwizzle swiz = NO_SWIZZLE;
+	switch(get_base_pixelformat(fmt))
 	{
-		if(fmt==LUMINANCE)
-		{
-			fmt = RED;
-			swizzle = R_TO_LUMINANCE;
-		}
-		else if(fmt==LUMINANCE_ALPHA)
-		{
-			fmt = RG;
-			swizzle = RG_TO_LUMINANCE_ALPHA;
-		}
+	case LUMINANCE:
+		fmt = RED;
+		swiz = R_TO_LUMINANCE;
+		break;
+	case LUMINANCE_ALPHA:
+		fmt = RG;
+		swiz = RG_TO_LUMINANCE_ALPHA;
+		break;
+	default:;
 	}
 
 	if(!get_component_size(fmt) && OES_required_internalformat)
 		fmt = get_default_sized_pixelformat(fmt);
 
 	require_pixelformat(fmt);
+	if(swiz!=NO_SWIZZLE)
+		static Require _req(ARB_texture_swizzle);
 	ifmt = fmt;
+	swizzle = swiz;
 }
 
 PixelFormat Texture::get_upload_format(PixelFormat fmt) const