From 8f373af3e375799dd739fe932bc697e8595756b4 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 3 Nov 2016 12:50:35 +0200
Subject: [PATCH] Expand the PixelFormat conversion API

Get_sized_pixelformat now takes an explicit size parameter.  The decision
between 16-bit and 32-bit depth component formats has been moved to
Texture::set_internal_format.

Get_unsized_pixelformat was added as an intermediate step for
get_base_pixelformat.  It preserves sRGB information.
---
 source/pixelformat.cpp | 103 ++++++++++++++++++++++++++++++-----------
 source/pixelformat.h   |   3 +-
 source/texture.cpp     |   7 ++-
 3 files changed, 82 insertions(+), 31 deletions(-)

diff --git a/source/pixelformat.cpp b/source/pixelformat.cpp
index 320fef1f..d866bcf8 100644
--- a/source/pixelformat.cpp
+++ b/source/pixelformat.cpp
@@ -77,6 +77,19 @@ PixelFormat storage_pixelformat_from_graphics(Graphics::PixelFormat pf, bool srg
 }
 
 PixelFormat get_base_pixelformat(PixelFormat pf)
+{
+	PixelFormat unsized = get_unsized_pixelformat(pf);
+	switch(unsized)
+	{
+	case SRGB: return RGB;
+	case SRGB_ALPHA: return RGBA;
+	case SLUMINANCE: return LUMINANCE;
+	case SLUMINANCE_ALPHA: return LUMINANCE_ALPHA;
+	default: return unsized;
+	}
+}
+
+PixelFormat get_unsized_pixelformat(PixelFormat pf)
 {
 	switch(pf)
 	{
@@ -88,20 +101,16 @@ PixelFormat get_base_pixelformat(PixelFormat pf)
 	case RG32F: return RG;
 	case RGB8:
 	case RGB16F:
-	case RGB32F:
-	case SRGB:
-	case SRGB8: return RGB;
+	case RGB32F: return RGB;
+	case SRGB8: return SRGB;
 	case RGBA8:
 	case RGBA16F:
-	case RGBA32F:
-	case SRGB_ALPHA:
-	case SRGB8_ALPHA8: return RGBA;
-	case LUMINANCE8:
-	case SLUMINANCE:
-	case SLUMINANCE8: return LUMINANCE;
-	case LUMINANCE_ALPHA8:
-	case SLUMINANCE_ALPHA:
-	case SLUMINANCE8_ALPHA8: return LUMINANCE_ALPHA;
+	case RGBA32F: return RGBA;
+	case SRGB8_ALPHA8: return SRGB_ALPHA;
+	case LUMINANCE8: return LUMINANCE;
+	case SLUMINANCE8: return SLUMINANCE;
+	case LUMINANCE_ALPHA8: return LUMINANCE_ALPHA;
+	case SLUMINANCE8_ALPHA8: return SLUMINANCE_ALPHA;
 	case DEPTH_COMPONENT16:
 	case DEPTH_COMPONENT24:
 	case DEPTH_COMPONENT32: return DEPTH_COMPONENT;
@@ -109,26 +118,64 @@ PixelFormat get_base_pixelformat(PixelFormat pf)
 	}
 }
 
-PixelFormat get_sized_pixelformat(PixelFormat pf)
+PixelFormat get_sized_pixelformat(PixelFormat pf, unsigned size)
 {
+	if(!size || size>4)
+		throw invalid_argument("get_sized_pixelformat");
+
 	switch(pf)
 	{
-	case RED: return R8;
-	case RG: return RG8;
-	case RGB: return RGB8;
-	case RGBA: return RGBA8;
-	case SRGB: return SRGB8;
-	case SRGB_ALPHA: return SRGB8_ALPHA8;
-	case LUMINANCE: return LUMINANCE8;
-	case SLUMINANCE: return SLUMINANCE8;
-	case LUMINANCE_ALPHA: return LUMINANCE8_ALPHA8;
-	case SLUMINANCE_ALPHA: return SLUMINANCE8_ALPHA8;
-	case DEPTH_COMPONENT:
-		if(get_gl_api()==OPENGL_ES2)
-			return DEPTH_COMPONENT16;
+	case SRGB:
+	case SRGB_ALPHA: break;
+	case SRGB8: pf = SRGB; break;
+	case SRGB8_ALPHA8: pf = SRGB_ALPHA; break;
+	default: pf = get_base_pixelformat(pf);
+	}
+
+	switch(size)
+	{
+	case 1:
+		switch(pf)
+		{
+		case RED: return R8;
+		case RG: return RG8;
+		case RGB: return RGB8;
+		case RGBA: return RGBA8;
+		case SRGB: return SRGB8;
+		case SRGB_ALPHA: return SRGB8_ALPHA8;
+		case LUMINANCE: return LUMINANCE8;
+		case SLUMINANCE: return SLUMINANCE8;
+		case LUMINANCE_ALPHA: return LUMINANCE8_ALPHA8;
+		case SLUMINANCE_ALPHA: return SLUMINANCE8_ALPHA8;
+		default: throw invalid_argument("get_sized_pixelformat");
+		}
+	case 2:
+		switch(pf)
+		{
+		case RED: return R16F;
+		case RG: return RG16F;
+		case RGB: return RGB16F;
+		case RGBA: return RGBA16F;
+		case DEPTH_COMPONENT: return DEPTH_COMPONENT16;
+		default: throw invalid_argument("get_sized_pixelformat");
+		}
+	case 3:
+		if(pf==DEPTH_COMPONENT)
+			return DEPTH_COMPONENT24;
 		else
-			return DEPTH_COMPONENT32;
-	default: return pf;
+			throw invalid_argument("get_sized_pixelformat");
+	case 4:
+		switch(pf)
+		{
+		case RED: return R32F;
+		case RG: return RG32F;
+		case RGB: return RGB32F;
+		case RGBA: return RGBA32F;
+		case DEPTH_COMPONENT: return DEPTH_COMPONENT32;
+		default: throw invalid_argument("get_sized_pixelformat");
+		}
+	default:
+		throw invalid_argument("get_sized_pixelformat");
 	}
 }
 
diff --git a/source/pixelformat.h b/source/pixelformat.h
index 17a90d36..dcbb5948 100644
--- a/source/pixelformat.h
+++ b/source/pixelformat.h
@@ -63,7 +63,8 @@ PixelFormat pixelformat_from_graphics(Graphics::PixelFormat);
 PixelFormat storage_pixelformat_from_graphics(Graphics::PixelFormat, bool = false);
 
 PixelFormat get_base_pixelformat(PixelFormat);
-PixelFormat get_sized_pixelformat(PixelFormat);
+PixelFormat get_unsized_pixelformat(PixelFormat);
+PixelFormat get_sized_pixelformat(PixelFormat, unsigned = 1);
 PixelFormat get_srgb_pixelformat(PixelFormat);
 unsigned get_component_count(PixelFormat);
 unsigned get_component_size(PixelFormat);
diff --git a/source/texture.cpp b/source/texture.cpp
index 21fc7a6a..b545b166 100644
--- a/source/texture.cpp
+++ b/source/texture.cpp
@@ -87,8 +87,11 @@ DataType Texture::get_alloc_type(PixelFormat fmt)
 
 void Texture::set_internal_format(PixelFormat fmt)
 {
-	if(MSP_sized_internal_formats)
-		fmt = get_sized_pixelformat(fmt);
+	if(!get_component_size(fmt) && MSP_sized_internal_formats)
+	{
+		unsigned size = (fmt==DEPTH_COMPONENT ? get_gl_api()==OPENGL_ES2 ? 2 : 4 : 1);
+		fmt = get_sized_pixelformat(fmt, size);
+	}
 
 	require_pixelformat(fmt);
 	ifmt = fmt;
-- 
2.45.2