From f2f0355d940bf261dc5c31bc0020e4931da98e45 Mon Sep 17 00:00:00 2001
From: Henrik Rydgard <hrydgard@gmail.com>
Date: Mon, 24 Mar 2014 10:55:07 +0100
Subject: [PATCH] Split up ApplyShader into ApplyVertexShader and
 ApplyFragmentShader.

Will allow the alphatest avoiding optimization later.
---
 GPU/GLES/ShaderManager.cpp     | 29 ++++++++++++++++++-----------
 GPU/GLES/ShaderManager.h       | 12 +++++++++++-
 GPU/GLES/TransformPipeline.cpp |  7 +++++--
 3 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/GPU/GLES/ShaderManager.cpp b/GPU/GLES/ShaderManager.cpp
index b3924e2b8f..d6010ca4fc 100644
--- a/GPU/GLES/ShaderManager.cpp
+++ b/GPU/GLES/ShaderManager.cpp
@@ -82,7 +82,7 @@ Shader::~Shader() {
 LinkedShader::LinkedShader(Shader *vs, Shader *fs, u32 vertType, bool useHWTransform, LinkedShader *previous)
 		: useHWTransform_(useHWTransform), program(0), dirtyUniforms(0) {
 	program = glCreateProgram();
-
+	vs_ = vs;
 	glAttachShader(program, vs->shader);
 	glAttachShader(program, fs->shader);
 
@@ -605,8 +605,7 @@ void ShaderManager::DirtyLastShader() { // disables vertex arrays
 	lastShader_ = 0;
 }
 
-
-LinkedShader *ShaderManager::ApplyShader(int prim, u32 vertType) {
+Shader *ShaderManager::ApplyVertexShader(int prim, u32 vertType) {
 	// This doesn't work - we miss some events that really do need to dirty the prescale.
 	// like changing the texmapmode.
 	// if (g_Config.bPrescaleUV)
@@ -622,18 +621,20 @@ LinkedShader *ShaderManager::ApplyShader(int prim, u32 vertType) {
 	bool useHWTransform = CanUseHardwareTransform(prim);
 
 	VertexShaderID VSID;
-	FragmentShaderID FSID;
 	ComputeVertexShaderID(&VSID, vertType, prim, useHWTransform);
-	ComputeFragmentShaderID(&FSID);
+	ComputeFragmentShaderID(&FSID_);
 
 	// Just update uniforms if this is the same shader as last time.
-	if (lastShader_ != 0 && VSID == lastVSID_ && FSID == lastFSID_) {
+	if (lastShader_ != 0 && VSID == lastVSID_ && FSID_ == lastFSID_) {
 		lastShader_->UpdateUniforms(vertType);
-		return lastShader_;	// Already all set.
+		lastShaderSame_ = true;
+		return lastShader_->vs_;	// Already all set.
+	} else {
+		lastShaderSame_ = false;
 	}
 
 	lastVSID_ = VSID;
-	lastFSID_ = FSID;
+	lastFSID_ = FSID_;
 
 	VSCache::iterator vsIter = vsCache_.find(VSID);
 	Shader *vs;
@@ -660,14 +661,20 @@ LinkedShader *ShaderManager::ApplyShader(int prim, u32 vertType) {
 	} else {
 		vs = vsIter->second;
 	}
+	return vs;
+}
 
-	FSCache::iterator fsIter = fsCache_.find(FSID);
+LinkedShader *ShaderManager::ApplyFragmentShader(Shader *vs, int prim, u32 vertType) {
+	if (lastShaderSame_)
+		return lastShader_;
+
+	FSCache::iterator fsIter = fsCache_.find(FSID_);
 	Shader *fs;
 	if (fsIter == fsCache_.end())	{
 		// Fragment shader not in cache. Let's compile it.
 		GenerateFragmentShader(codeBuffer_);
-		fs = new Shader(codeBuffer_, GL_FRAGMENT_SHADER, useHWTransform);
-		fsCache_[FSID] = fs;
+		fs = new Shader(codeBuffer_, GL_FRAGMENT_SHADER, vs->UseHWTransform());
+		fsCache_[FSID_] = fs;
 	} else {
 		fs = fsIter->second;
 	}
diff --git a/GPU/GLES/ShaderManager.h b/GPU/GLES/ShaderManager.h
index 9c18a12516..2a7bba13c3 100644
--- a/GPU/GLES/ShaderManager.h
+++ b/GPU/GLES/ShaderManager.h
@@ -47,6 +47,7 @@ public:
 	void stop();
 	void UpdateUniforms(u32 vertType);
 
+	Shader *vs_;
 	// Set to false if the VS failed, happens on Mali-400 a lot for complex shaders.
 	bool useHWTransform_;
 
@@ -167,7 +168,12 @@ public:
 	~ShaderManager();
 
 	void ClearCache(bool deleteThem);  // TODO: deleteThem currently not respected
-	LinkedShader *ApplyShader(int prim, u32 vertType);
+
+	// This is the old ApplyShader split into two parts, because of annoying information dependencies.
+	// If you call ApplyVertexShader, you MUST call ApplyFragmentShader soon afterwards.
+	Shader *ApplyVertexShader(int prim, u32 vertType);
+	LinkedShader *ApplyFragmentShader(Shader *vs, int prim, u32 vertType);
+
 	void DirtyShader();
 	void DirtyUniform(u32 what) {
 		globalDirty_ |= what;
@@ -192,6 +198,10 @@ private:
 	typedef std::vector<LinkedShaderCacheEntry> LinkedShaderCache;
 
 	LinkedShaderCache linkedShaderCache_;
+
+	FragmentShaderID FSID_;
+	bool lastShaderSame_;
+
 	FragmentShaderID lastFSID_;
 	VertexShaderID lastVSID_;
 
diff --git a/GPU/GLES/TransformPipeline.cpp b/GPU/GLES/TransformPipeline.cpp
index ab2174aefd..0b01d00a3a 100644
--- a/GPU/GLES/TransformPipeline.cpp
+++ b/GPU/GLES/TransformPipeline.cpp
@@ -526,12 +526,12 @@ void TransformDrawEngine::DoFlush() {
 	GEPrimitiveType prim = prevPrim_;
 	ApplyDrawState(prim);
 
-	LinkedShader *program = shaderManager_->ApplyShader(prim, lastVType_);
+	Shader *vshader = shaderManager_->ApplyVertexShader(prim, lastVType_);
 
 	// Compiler warns about this because it's only used in the #ifdeffed out RangeElements path.
 	int maxIndex = 0;
 
-	if (program->useHWTransform_) {
+	if (vshader->UseHWTransform()) {
 		GLuint vbo = 0, ebo = 0;
 		int vertexCount = 0;
 		bool useElements = true;
@@ -699,7 +699,9 @@ rotateVBO:
 
 		VERBOSE_LOG(G3D, "Flush prim %i! %i verts in one go", prim, vertexCount);
 
+		LinkedShader *program = shaderManager_->ApplyFragmentShader(vshader, prim, lastVType_);
 		SetupDecFmtForDraw(program, dec_->GetDecVtxFmt(), vbo ? 0 : decoded);
+
 		if (useElements) {
 #if 1  // USING_GLES2
 			glDrawElements(glprim[prim], vertexCount, GL_UNSIGNED_SHORT, ebo ? 0 : (GLvoid*)decIndex);
@@ -715,6 +717,7 @@ rotateVBO:
 			glBindBuffer(GL_ARRAY_BUFFER, 0);
 	} else {
 		DecodeVerts();
+		LinkedShader *program = shaderManager_->ApplyFragmentShader(vshader, prim, lastVType_);
 		gpuStats.numUncachedVertsDrawn += indexGen.VertexCount();
 		prim = indexGen.Prim();
 		// Undo the strip optimization, not supported by the SW code yet.