Improve depal shader failure cases.

Primarily, this handles lost (e.g. Android sleep) better, in that it
recreates the vertex shader.  Previously, this would simply cause all
future depal operations to fail, and to constantly retry compiling and
linking the failed program.

GPU/GLES/DepalettizeShader.cpp

@@ -94,18 +94,34 @@ DepalShaderCache::DepalShaderCache() {
 	// Pre-build the vertex program
 	useGL3_ = gl_extensions.GLES3 || gl_extensions.VersionGEThan(3, 3);
 
+	vertexShaderFailed_ = false;
+	vertexShader_ = 0;
+}
+
+DepalShaderCache::~DepalShaderCache() {
+	Clear();
+	if (vertexShader_) {
+		glDeleteShader(vertexShader_);
+	}
+}
+
+bool DepalShaderCache::CreateVertexShader() {
+	if (vertexShaderFailed_) {
+		return false;
+	}
+
 	vertexShader_ = glCreateShader(GL_VERTEX_SHADER);
 	glShaderSource(vertexShader_, 1, useGL3_ ? &depalVShader300 : &depalVShader100, 0);
 	glCompileShader(vertexShader_);
 
 	if (!CheckShaderCompileSuccess(vertexShader_, useGL3_ ? depalVShader300 : depalVShader100)) {
-		// ...
+		glDeleteShader(vertexShader_);
+		vertexShader_ = 0;
+		// Don't try to recompile.
+		vertexShaderFailed_ = true;
 	}
-}
 
-DepalShaderCache::~DepalShaderCache() {
-	Clear();
-	glDeleteShader(vertexShader_);
+	return !vertexShaderFailed_;
 }
 
 u32 DepalShaderCache::GenerateShaderID(GEBufferFormat pixelFormat) {
@@ -152,7 +168,9 @@ GLuint DepalShaderCache::GetClutTexture(const u32 clutID, u32 *rawClut) {
 void DepalShaderCache::Clear() {
 	for (auto shader = cache_.begin(); shader != cache_.end(); ++shader) {
 		glDeleteShader(shader->second->fragShader);
-		glDeleteProgram(shader->second->program);
+		if (shader->second->program) {
+			glDeleteProgram(shader->second->program);
+		}
 		delete shader->second;
 	}
 	cache_.clear();
@@ -183,6 +201,13 @@ GLuint DepalShaderCache::GetDepalettizeShader(GEBufferFormat pixelFormat) {
 		return shader->second->program;
 	}
 
+	if (vertexShader_ == 0) {
+		if (!CreateVertexShader()) {
+			// The vertex shader failed, no need to bother trying the fragment.
+			return 0;
+		}
+	}
+
 	char *buffer = new char[2048];
 
 	GenerateDepalShader(buffer, pixelFormat, useGL3_ ? GLSL_300 : GLSL_140);
@@ -211,6 +236,11 @@ GLuint DepalShaderCache::GetDepalettizeShader(GEBufferFormat pixelFormat) {
 	glUniform1i(u_tex, 0);
 	glUniform1i(u_pal, 3);
 
+	DepalShader *depal = new DepalShader();
+	depal->program = program;
+	depal->fragShader = fragShader;
+	cache_[id] = depal;
+
 	GLint linkStatus = GL_FALSE;
 	glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
 	if (linkStatus != GL_TRUE) {
@@ -227,17 +257,14 @@ GLuint DepalShaderCache::GetDepalettizeShader(GEBufferFormat pixelFormat) {
 			delete[] errorbuf;	// we're dead!
 		}
 
-		delete[] buffer;
-		return 0;
+		// Since it failed, let's mark it in the cache so we don't keep retrying.
+		// That will only make it slower.
+		depal->program = 0;
+
+		// We will delete the shader later in Clear().
+		glDeleteProgram(program);
 	}
 
-	DepalShader *depal = new DepalShader();
-	depal->program = program;
-	depal->fragShader = fragShader;
-
-	cache_[id] = depal;
-
 	delete[] buffer;
-
 	return depal->program;
 }

GPU/GLES/DepalettizeShader.h

@@ -47,8 +47,10 @@ public:
 
 private:
 	u32 GenerateShaderID(GEBufferFormat pixelFormat);
+	bool CreateVertexShader();
 
 	bool useGL3_;
+	bool vertexShaderFailed_;
 	GLuint vertexShader_;
 	std::map<u32, DepalShader *> cache_;
 	std::map<u32, DepalTexture *> texCache_;