From e9885141e4049a06b89000bf34959174fb2d4491 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Fri, 8 Jun 2018 14:15:59 +0200
Subject: Expose compute shader state

---
 src/shader/util.cc                | 11 ++++++++++-
 src/shader/wrap/compute_shader.cc | 13 +++++++++++--
 src/shader/wrap/compute_shader.h  |  4 ++++
 src/shader/wrap/graphic_shader.h  |  2 --
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/src/shader/util.cc b/src/shader/util.cc
index 07a1128..be59ac1 100644
--- a/src/shader/util.cc
+++ b/src/shader/util.cc
@@ -7,9 +7,12 @@ namespace util {
 
 GLint getUniform(GLuint program, const std::string& name) {
 	const GLint uniform = glGetUniformLocation(program, name.c_str());
+
 	if ( uniform == -1 ) {
 		std::cerr << "Could not bind uniform " << name << std::endl;
+		return -1;
 	}
+
 	return uniform;
 }
 
@@ -18,7 +21,7 @@ GLint compileShader(const std::string& source, GLenum type) {
 
 	if ( !shader ) {
 		std::cerr << "Cannot create a shader of type " << type << std::endl;
-		exit(-1);
+		return -1;
 	}
 
 	const char* source_data = source.c_str();
@@ -29,16 +32,22 @@ GLint compileShader(const std::string& source, GLenum type) {
 
 	GLint compiled;
 	glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+
 	if ( !compiled ) {
 		std::cerr << "Cannot compile shader" << std::endl;
+
 		GLint maxLength = 0;
 		glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &maxLength);
+
 		std::vector<GLchar> errorLog(maxLength);
 		glGetShaderInfoLog(shader, maxLength, &maxLength, &errorLog[0]);
+
 		for( auto c : errorLog ) {
 			std::cerr << c;
 		}
 		std::cerr << std::endl;
+
+		return -1;
 	}
 
 	return shader;
diff --git a/src/shader/wrap/compute_shader.cc b/src/shader/wrap/compute_shader.cc
index 97ce52a..e91ba77 100644
--- a/src/shader/wrap/compute_shader.cc
+++ b/src/shader/wrap/compute_shader.cc
@@ -17,14 +17,23 @@ ComputeShader::Guard ComputeShader::use() const {
 
 ComputeShader::ComputeShader(const std::string& src):
 	_id(glCreateProgram()) {
-	glAttachShader(_id, util::compileShader(src, GL_COMPUTE_SHADER));
-	glLinkProgram(_id);
+	GLint shader = util::compileShader(src, GL_COMPUTE_SHADER);
+
+	if ( shader != -1 ) {
+		glAttachShader(_id, shader);
+		glLinkProgram(_id);
+		_good = true;
+	}
 }
 
 ComputeShader::~ComputeShader() {
 	glDeleteProgram(_id);
 }
 
+bool ComputeShader::isGood() const {
+	return _good;
+}
+
 GLuint ComputeShader::setUniform(const std::string& name, float x, float y) const {
 	GLuint id = util::getUniform(_id, name);
 	glUniform2f(id, x, y);
diff --git a/src/shader/wrap/compute_shader.h b/src/shader/wrap/compute_shader.h
index e9e88ca..ffdde59 100644
--- a/src/shader/wrap/compute_shader.h
+++ b/src/shader/wrap/compute_shader.h
@@ -8,6 +8,8 @@ class ComputeShader {
 private:
 	const GLuint _id;
 
+	bool _good;
+
 public:
 	struct Guard {
 		const GLuint _id;
@@ -21,6 +23,8 @@ public:
 	ComputeShader(const std::string& src);
 	~ComputeShader();
 
+	bool isGood() const;
+
 	GLuint setUniform(const std::string& name, float x, float y) const;
 
 	void workOn(GLuint buffer) const;
diff --git a/src/shader/wrap/graphic_shader.h b/src/shader/wrap/graphic_shader.h
index 82f7e7a..25a5efb 100644
--- a/src/shader/wrap/graphic_shader.h
+++ b/src/shader/wrap/graphic_shader.h
@@ -6,8 +6,6 @@
 #include <GL/glew.h>
 #include <glm/glm.hpp>
 
-#include "shader/util.h"
-
 class GraphicShader {
 private:
 	const GLuint _id;
-- 
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