From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 3 Nov 2016 11:12:06 +0000 (+0200)
Subject: Prefer RG pixelformats over LUMINANCE
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=1955e583d7eeeb0a2ff054d90c3694f575d9a08d;p=libs%2Fgl.git

Prefer RG pixelformats over LUMINANCE

LUMINANCE formats were deprecated in OpenGL 3.0.  ARB_texture_swizzle
was not promoted to core until 3.3, so it's possible this won't work on
some transition period hardware.

SLUMINANCE formats are marked as deprecated in mspgl since it's not
possible to properly emulate them through swizzling.
---

diff --git a/extensions/arb_texture_swizzle.glext b/extensions/arb_texture_swizzle.glext
new file mode 100644
index 00000000..52496521
--- /dev/null
+++ b/extensions/arb_texture_swizzle.glext
@@ -0,0 +1 @@
+extension ARB_texture_swizzle
diff --git a/source/pixelformat.h b/source/pixelformat.h
index dcbb5948..14ca580e 100644
--- a/source/pixelformat.h
+++ b/source/pixelformat.h
@@ -48,6 +48,8 @@ enum PixelFormat
 	LUMINANCE8      = GL_LUMINANCE8,
 	LUMINANCE_ALPHA    = GL_LUMINANCE_ALPHA,
 	LUMINANCE8_ALPHA8  = GL_LUMINANCE8_ALPHA8,
+
+	// Deprecated
 	SLUMINANCE         = GL_SLUMINANCE,
 	SLUMINANCE8        = GL_SLUMINANCE8,
 	SLUMINANCE_ALPHA   = GL_SLUMINANCE_ALPHA,
diff --git a/source/texture.cpp b/source/texture.cpp
index b545b166..18746e5f 100644
--- a/source/texture.cpp
+++ b/source/texture.cpp
@@ -1,5 +1,6 @@
 #include <msp/gl/extensions/arb_direct_state_access.h>
 #include <msp/gl/extensions/arb_shadow.h>
+#include <msp/gl/extensions/arb_texture_swizzle.h>
 #include <msp/gl/extensions/ext_framebuffer_object.h>
 #include <msp/gl/extensions/ext_texture3d.h>
 #include <msp/gl/extensions/ext_texture_filter_anisotropic.h>
@@ -49,6 +50,13 @@ void operator>>(const LexicalConverter &c, TextureWrap &tw)
 }
 
 
+int Texture::swizzle_orders[] =
+{
+	GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA,
+	GL_RED, GL_RED, GL_RED, GL_ONE,
+	GL_RED, GL_RED, GL_RED, GL_GREEN
+};
+
 Texture::Texture(GLenum t, ResourceManager *m):
 	id(0),
 	target(t),
@@ -93,8 +101,34 @@ void Texture::set_internal_format(PixelFormat fmt)
 		fmt = get_sized_pixelformat(fmt, size);
 	}
 
+	FormatSwizzle swiz = NO_SWIZZLE;
+	if(ARB_texture_rg && ARB_texture_swizzle)
+	{
+		if(fmt==LUMINANCE8 || fmt==SLUMINANCE8)
+		{
+			fmt = R8;
+			swiz = R_TO_LUMINANCE;
+		}
+		else if(fmt==LUMINANCE8_ALPHA8 || fmt==SLUMINANCE8_ALPHA8)
+		{
+			fmt = RG8;
+			swiz = RG_TO_LUMINANCE_ALPHA;
+		}
+	}
+
 	require_pixelformat(fmt);
 	ifmt = fmt;
+	swizzle = swiz;
+	if(swizzle)
+		update_parameter(FORMAT_SWIZZLE);
+}
+
+PixelFormat Texture::get_upload_format(PixelFormat fmt) const
+{
+	if(fmt==LUMINANCE || fmt==LUMINANCE_ALPHA)
+		return get_base_pixelformat(ifmt);
+	else
+		return fmt;
 }
 
 void Texture::update_parameter(int mask) const
@@ -129,6 +163,13 @@ void Texture::update_parameter(int mask) const
 		set_parameter_i(GL_TEXTURE_COMPARE_MODE, (compare ? GL_COMPARE_R_TO_TEXTURE : GL_NONE));
 	if(mask&COMPARE_FUNC)
 		set_parameter_i(GL_TEXTURE_COMPARE_FUNC, cmp_func);
+	if(mask&FORMAT_SWIZZLE)
+	{
+		if(ARB_direct_state_access)
+			glTextureParameteriv(id, GL_TEXTURE_SWIZZLE_RGBA, swizzle_orders+swizzle*4);
+		else
+			glTexParameteriv(target, GL_TEXTURE_SWIZZLE_RGBA, swizzle_orders+swizzle*4);
+	}
 }
 
 void Texture::set_parameter_i(GLenum param, int value) const
diff --git a/source/texture.h b/source/texture.h
index 1b80e950..abccb8d8 100644
--- a/source/texture.h
+++ b/source/texture.h
@@ -104,12 +104,21 @@ protected:
 		GENERATE_MIPMAP = 32,
 		COMPARE = 64,
 		COMPARE_FUNC = 128,
-		MAX_ANISOTROPY = 256
+		MAX_ANISOTROPY = 256,
+		FORMAT_SWIZZLE = 512
+	};
+
+	enum FormatSwizzle
+	{
+		NO_SWIZZLE,
+		R_TO_LUMINANCE,
+		RG_TO_LUMINANCE_ALPHA
 	};
 
 	unsigned id;
 	GLenum target;
 	PixelFormat ifmt;
+	FormatSwizzle swizzle;
 	TextureFilter min_filter;
 	TextureFilter mag_filter;
 	float max_anisotropy;
@@ -121,6 +130,8 @@ protected:
 	Predicate cmp_func;
 	mutable int dirty_params;
 
+	static int swizzle_orders[];
+
 	Texture(GLenum, ResourceManager * = 0);
 	Texture(const Texture &);
 	Texture &operator=(const Texture &);
@@ -130,6 +141,7 @@ public:
 protected:
 	static DataType get_alloc_type(PixelFormat);
 	void set_internal_format(PixelFormat);
+	PixelFormat get_upload_format(PixelFormat) const;
 
 	void update_parameter(int) const;
 	void set_parameter_i(GLenum, int) const;
diff --git a/source/texture1d.cpp b/source/texture1d.cpp
index 6affe899..e25a11c0 100644
--- a/source/texture1d.cpp
+++ b/source/texture1d.cpp
@@ -65,7 +65,7 @@ void Texture1D::image(unsigned level, PixelFormat fmt, DataType type, const void
 		return sub_image(level, 0, w, fmt, type, data);
 
 	BindRestore _bind(this);
-	glTexImage1D(target, level, ifmt, w, 0, fmt, type, data);
+	glTexImage1D(target, level, ifmt, w, 0, get_upload_format(fmt), type, data);
 
 	allocated |= 1<<level;
 	if(gen_mipmap && level==0)
@@ -83,6 +83,7 @@ void Texture1D::sub_image(unsigned level, int x, unsigned wd, PixelFormat fmt, D
 	Conditional<BindRestore> _bind(!ARB_direct_state_access, this);
 	allocate(level);
 
+	fmt = get_upload_format(fmt);
 	if(ARB_direct_state_access)
 		glTextureSubImage1D(id, level, x, wd, fmt, type, data);
 	else
diff --git a/source/texture2d.cpp b/source/texture2d.cpp
index e15f9a33..7ce18d00 100644
--- a/source/texture2d.cpp
+++ b/source/texture2d.cpp
@@ -95,7 +95,7 @@ void Texture2D::image(unsigned level, PixelFormat fmt, DataType type, const void
 		return sub_image(level, 0, 0, w, h, fmt, type, data);
 
 	BindRestore _bind(this);
-	glTexImage2D(target, level, ifmt, w, h, 0, fmt, type, data);
+	glTexImage2D(target, level, ifmt, w, h, 0, get_upload_format(fmt), type, data);
 
 	allocated |= 1<<level;
 	if(gen_mipmap && level==0)
@@ -113,6 +113,7 @@ void Texture2D::sub_image(unsigned level, int x, int y, unsigned wd, unsigned ht
 	Conditional<BindRestore> _bind(!ARB_direct_state_access, this);
 	allocate(level);
 
+	fmt = get_upload_format(fmt);
 	if(ARB_direct_state_access)
 		glTextureSubImage2D(id, level, x, y, wd, ht, fmt, type, data);
 	else
diff --git a/source/texture3d.cpp b/source/texture3d.cpp
index 680880a8..85b3f075 100644
--- a/source/texture3d.cpp
+++ b/source/texture3d.cpp
@@ -83,7 +83,7 @@ void Texture3D::image(unsigned level, PixelFormat fmt, DataType type, const void
 		return sub_image(level, 0, 0, 0, w, h, d, fmt, type, data);
 
 	BindRestore _bind(this);
-	glTexImage3D(target, level, ifmt, width, height, depth, 0, fmt, type, data);
+	glTexImage3D(target, level, ifmt, width, height, depth, 0, get_upload_format(fmt), type, data);
 
 	allocated |= 1<<level;
 	if(gen_mipmap && level==0)
@@ -101,6 +101,7 @@ void Texture3D::sub_image(unsigned level, int x, int y, int z, unsigned wd, unsi
 	Conditional<BindRestore> _bind(!ARB_direct_state_access, this);
 	allocate(level);
 
+	fmt = get_upload_format(fmt);
 	if(ARB_direct_state_access)
 		glTextureSubImage3D(id, level, x, y, z, wd, ht, dp, fmt, type, data);
 	else
diff --git a/source/texturecube.cpp b/source/texturecube.cpp
index 19c3bf07..db679cf9 100644
--- a/source/texturecube.cpp
+++ b/source/texturecube.cpp
@@ -96,7 +96,7 @@ void TextureCube::image(TextureCubeFace face, unsigned level, PixelFormat fmt, D
 		return sub_image(face, level, 0, 0, s, s, fmt, type, data);
 
 	BindRestore _bind(this);
-	glTexImage2D(face, level, ifmt, s, s, 0, fmt, type, data);
+	glTexImage2D(face, level, ifmt, s, s, 0, get_upload_format(fmt), type, data);
 
 	// XXX Allocation should be tracked per-face, but we'll run out of bits
 	allocated |= 1<<level;
@@ -116,7 +116,7 @@ void TextureCube::sub_image(TextureCubeFace face, unsigned level, int x, int y,
 	BindRestore _bind(this);
 	allocate(level);
 
-	glTexSubImage2D(face, level, x, y, wd, ht, fmt, type, data);
+	glTexSubImage2D(face, level, x, y, wd, ht, get_upload_format(fmt), type, data);
 
 	if(gen_mipmap && level==0)
 		auto_generate_mipmap();