OpenGL plugin: Support for dual-source blending, CURRENTLY DISABLED. It doesn't work yet. To fix it, we may need to convert all our shaders to GLSL so that we can use glBindFragDataLocation.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@6306 8ced0084-cf51-0410-be5f-012b33b47a6e

3 files changed, 64 insertions, 8 deletions

diff --git a/Source/Plugins/Plugin_VideoOGL/Src/GLUtil.h b/Source/Plugins/Plugin_VideoOGL/Src/GLUtil.h
index c0fb1a55f3..754a094cdb 100644
--- a/Source/Plugins/Plugin_VideoOGL/Src/GLUtil.h
+++ b/Source/Plugins/Plugin_VideoOGL/Src/GLUtil.h
@@ -136,4 +136,9 @@ extern CGcontext g_cgcontext;
 extern CGprofile g_cgvProf, g_cgfProf;
 #endif
 
+// XXX: Dual-source blending in OpenGL does not work correctly yet. To make it
+// work, we may need to use glBindFragDataLocation. To use that, we need to
+// use GLSL shaders across the whole pipeline. Yikes!
+const bool USE_DUAL_SOURCE_BLEND = false;
+
 #endif  // _GLINIT_H_
diff --git a/Source/Plugins/Plugin_VideoOGL/Src/Render.cpp b/Source/Plugins/Plugin_VideoOGL/Src/Render.cpp
index b9882f1087..44c84aaf8f 100644
--- a/Source/Plugins/Plugin_VideoOGL/Src/Render.cpp
+++ b/Source/Plugins/Plugin_VideoOGL/Src/Render.cpp
@@ -151,7 +151,7 @@ static const GLenum glSrcFactors[8] =
 	GL_DST_COLOR,
 	GL_ONE_MINUS_DST_COLOR,
 	GL_SRC_ALPHA,
-	GL_ONE_MINUS_SRC_ALPHA,
+	GL_ONE_MINUS_SRC_ALPHA, // NOTE: If dual-source blending is enabled, use SRC1_ALPHA
 	GL_DST_ALPHA,
 	GL_ONE_MINUS_DST_ALPHA
 };
@@ -162,7 +162,7 @@ static const GLenum glDestFactors[8] = {
 	GL_SRC_COLOR,
 	GL_ONE_MINUS_SRC_COLOR,
 	GL_SRC_ALPHA,
-	GL_ONE_MINUS_SRC_ALPHA,
+	GL_ONE_MINUS_SRC_ALPHA, // NOTE: If dual-source blending is enabled, use SRC1_ALPHA
 	GL_DST_ALPHA,
 	GL_ONE_MINUS_DST_ALPHA
 };
@@ -1034,17 +1034,47 @@ void Renderer::SetBlendMode(bool forceUpdate)
 
 	u32 changes = forceUpdate ? 0xFFFFFFFF : newval ^ s_blendMode;
 
+	bool useDstAlpha = !g_ActiveConfig.bDstAlphaPass && bpmem.dstalpha.enable && bpmem.blendmode.alphaupdate
+		&& bpmem.zcontrol.pixel_format == PIXELFMT_RGBA6_Z24;
+	bool useDualSource = USE_DUAL_SOURCE_BLEND && useDstAlpha && GLEW_ARB_blend_func_extended;
+
 	if (changes & 1)
 		// blend enable change
 		(newval & 1) ? glEnable(GL_BLEND) : glDisable(GL_BLEND);
 
 	if (changes & 4)
+	{
 		// subtract enable change
-		glBlendEquation(newval & 4 ? GL_FUNC_REVERSE_SUBTRACT : GL_FUNC_ADD);
+		GLenum equation = newval & 4 ? GL_FUNC_REVERSE_SUBTRACT : GL_FUNC_ADD;
+		GLenum equationAlpha = useDualSource ? GL_FUNC_ADD : equation;
+		glBlendEquationSeparate(equation, equationAlpha);
+	}
 
 	if (changes & 0x1F8)
+	{
+		GLenum srcFactor = glSrcFactors[(newval >> 3) & 7];
+		GLenum srcFactorAlpha = srcFactor;
+		GLenum dstFactor = glDestFactors[(newval >> 6) & 7];
+		GLenum dstFactorAlpha = dstFactor;
+		if (useDualSource)
+		{
+			srcFactorAlpha = GL_ONE;
+			dstFactorAlpha = GL_ZERO;
+
+			if (srcFactor == GL_SRC_ALPHA)
+				srcFactor = GL_SRC1_ALPHA;
+			else if (srcFactor == GL_ONE_MINUS_SRC_ALPHA)
+				srcFactor = GL_ONE_MINUS_SRC1_ALPHA;
+
+			if (dstFactor == GL_SRC_ALPHA)
+				dstFactor = GL_SRC1_ALPHA;
+			else if (dstFactor == GL_ONE_MINUS_SRC_ALPHA)
+				dstFactor = GL_ONE_MINUS_SRC1_ALPHA;
+		}
+
 		// blend RGB change
-		glBlendFunc(glSrcFactors[(newval >> 3) & 7], glDestFactors[(newval >> 6) & 7]);
+		glBlendFuncSeparate(srcFactor, dstFactor, srcFactorAlpha, dstFactorAlpha);
+	}
 
 	s_blendMode = newval;
 }
diff --git a/Source/Plugins/Plugin_VideoOGL/Src/VertexManager.cpp b/Source/Plugins/Plugin_VideoOGL/Src/VertexManager.cpp
index ef308524d7..58e677d563 100644
--- a/Source/Plugins/Plugin_VideoOGL/Src/VertexManager.cpp
+++ b/Source/Plugins/Plugin_VideoOGL/Src/VertexManager.cpp
@@ -184,8 +184,31 @@ void VertexManager::vFlush()
 	VertexShaderManager::SetConstants();
 	PixelShaderManager::SetConstants();
 
+	bool useDstAlpha = !g_ActiveConfig.bDstAlphaPass && bpmem.dstalpha.enable && bpmem.blendmode.alphaupdate
+		&& bpmem.zcontrol.pixel_format == PIXELFMT_RGBA6_Z24;
+	bool dualSourcePossible = USE_DUAL_SOURCE_BLEND && GLEW_ARB_blend_func_extended;
+
 	// finally bind
-	FRAGMENTSHADER* ps = PixelShaderCache::SetShader(DSTALPHA_NONE,g_nativeVertexFmt->m_components);
+	FRAGMENTSHADER* ps;
+	if (dualSourcePossible)
+	{
+		if (useDstAlpha)
+		{
+			// If host supports GL_ARB_blend_func_extended, we can do dst alpha in
+			// the same pass as regular rendering.
+			Renderer::SetBlendMode(true);
+			ps = PixelShaderCache::SetShader(DSTALPHA_DUAL_SOURCE_BLEND, g_nativeVertexFmt->m_components);
+		}
+		else
+		{
+			Renderer::SetBlendMode(true);
+			ps = PixelShaderCache::SetShader(DSTALPHA_NONE,g_nativeVertexFmt->m_components);
+		}
+	}
+	else
+	{
+		ps = PixelShaderCache::SetShader(DSTALPHA_NONE,g_nativeVertexFmt->m_components);
+	}
 	VERTEXSHADER* vs = VertexShaderCache::SetShader(g_nativeVertexFmt->m_components);
 	if (ps) PixelShaderCache::SetCurrentShader(ps->glprogid); // Lego Star Wars crashes here.
 	if (vs) VertexShaderCache::SetCurrentShader(vs->glprogid);
@@ -193,10 +216,8 @@ void VertexManager::vFlush()
 	Draw();
 
 	// run through vertex groups again to set alpha
-	if (!g_ActiveConfig.bDstAlphaPass && bpmem.dstalpha.enable && bpmem.blendmode.alphaupdate)
+	if (useDstAlpha && !dualSourcePossible)
 	{
-		// TODO: If host supports GL_ARB_blend_func_extended, use
-		// DSTALPHA_DUAL_SOURCE_BLEND and set blend modes accordingly.
 		ps = PixelShaderCache::SetShader(DSTALPHA_ALPHA_PASS,g_nativeVertexFmt->m_components);
 		if (ps) PixelShaderCache::SetCurrentShader(ps->glprogid);