From b4aa4bf0ac161fe1aff070324b3747e356ff112e Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Thu, 22 Nov 2018 05:31:10 +0100
Subject: [PATCH] - only use shader cache on Intel

---
 src/gl/shaders/gl_shader.cpp        | 22 +++++++++++++++++++---
 src/gl/shaders/gl_shaderprogram.cpp |  7 +++++--
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index c3c19df8c..0af60e412 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -56,10 +56,24 @@ struct ProgramBinary
 	TArray<uint8_t> data;
 };
 
-const char *ShaderMagic = "ZDSC";
+static const char *ShaderMagic = "ZDSC";
 
 static std::map<FString, std::unique_ptr<ProgramBinary>> ShaderCache; // Not a TMap because it doesn't support unique_ptr move semantics
 
+bool IsShaderCacheActive()
+{
+	static bool active = true;
+	static bool firstcall = true;
+
+	if (firstcall)
+	{
+		const char *vendor = (const char *)glGetString(GL_VENDOR);
+		active = strstr(vendor, "Intel") == nullptr;
+		firstcall = false;
+	}
+	return active;
+}
+
 static FString CalcProgramBinaryChecksum(const FString &vertex, const FString &fragment)
 {
 	const GLubyte *vendor = glGetString(GL_VENDOR);
@@ -421,7 +435,9 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 	FGLDebug::LabelObject(GL_PROGRAM, hShader, name);
 
 	uint32_t binaryFormat = 0;
-	TArray<uint8_t> binary = LoadCachedProgramBinary(vp_comb, fp_comb, binaryFormat);
+	TArray<uint8_t> binary;
+	if (IsShaderCacheActive())
+		binary = LoadCachedProgramBinary(vp_comb, fp_comb, binaryFormat);
 
 	bool linked = false;
 	if (binary.Size() > 0 && glProgramBinary)
@@ -481,7 +497,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 			// only print message if there's an error.
 			I_Error("Init Shader '%s':\n%s\n", name, error.GetChars());
 		}
-		else if (glProgramBinary)
+		else if (glProgramBinary && IsShaderCacheActive())
 		{
 			int binaryLength = 0;
 			glGetProgramiv(hShader, GL_PROGRAM_BINARY_LENGTH, &binaryLength);
diff --git a/src/gl/shaders/gl_shaderprogram.cpp b/src/gl/shaders/gl_shaderprogram.cpp
index 126817b59..8068b3c2c 100644
--- a/src/gl/shaders/gl_shaderprogram.cpp
+++ b/src/gl/shaders/gl_shaderprogram.cpp
@@ -37,6 +37,7 @@
 namespace OpenGLRenderer
 {
 
+bool IsShaderCacheActive();
 TArray<uint8_t> LoadCachedProgramBinary(const FString &vertex, const FString &fragment, uint32_t &binaryFormat);
 void SaveCachedProgramBinary(const FString &vertex, const FString &fragment, const TArray<uint8_t> &binary, uint32_t binaryFormat);
 
@@ -142,7 +143,9 @@ void FShaderProgram::Link(const char *name)
 	FGLDebug::LabelObject(GL_PROGRAM, mProgram, name);
 
 	uint32_t binaryFormat = 0;
-	TArray<uint8_t> binary = LoadCachedProgramBinary(mShaderSources[Vertex], mShaderSources[Fragment], binaryFormat);
+	TArray<uint8_t> binary;
+	if (IsShaderCacheActive())
+		binary = LoadCachedProgramBinary(mShaderSources[Vertex], mShaderSources[Fragment], binaryFormat);
 
 	bool loadedFromBinary = false;
 	if (binary.Size() > 0 && glProgramBinary)
@@ -168,7 +171,7 @@ void FShaderProgram::Link(const char *name)
 		{
 			I_FatalError("Link Shader '%s':\n%s\n", name, GetProgramInfoLog(mProgram).GetChars());
 		}
-		else if (glProgramBinary)
+		else if (glProgramBinary && IsShaderCacheActive())
 		{
 			int binaryLength = 0;
 			glGetProgramiv(mProgram, GL_PROGRAM_BINARY_LENGTH, &binaryLength);