Introduced an interface for specifying attribute bindings, taking the opportunity to document the interface and introduce exceptions.

Outputs/CRT/Internals/CRTOpenGL.cpp

@@ -246,7 +246,6 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 
 	_input_texture_data = (uint8_t *)glMapBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, _input_texture_array_size, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT);
 
-//	printf("%04x\n", glGetError());
 	_output_mutex->unlock();
 }
 
@@ -535,7 +534,7 @@ void OpenGLOutputBuilder::prepare_composite_input_shader()
 	char *fragment_shader = get_input_fragment_shader();
 	if(vertex_shader && fragment_shader)
 	{
-		composite_input_shader_program = std::unique_ptr<OpenGL::Shader>(new OpenGL::Shader(vertex_shader, fragment_shader));
+		composite_input_shader_program = std::unique_ptr<OpenGL::Shader>(new OpenGL::Shader(vertex_shader, fragment_shader, nullptr));
 
 		GLint texIDUniform				= composite_input_shader_program->get_uniform_location("texID");
 		GLint phaseCyclesPerTickUniform	= composite_input_shader_program->get_uniform_location("phaseCyclesPerTick");
@@ -622,7 +621,7 @@ std::unique_ptr<OpenGL::Shader> OpenGLOutputBuilder::prepare_output_shader(char
 
 	if(vertex_shader && fragment_shader)
 	{
-		shader_program = std::unique_ptr<OpenGL::Shader>(new OpenGL::Shader(vertex_shader, fragment_shader));
+		shader_program = std::unique_ptr<OpenGL::Shader>(new OpenGL::Shader(vertex_shader, fragment_shader, nullptr));
 		shader_program->bind();
 
 		windowSizeUniform			= shader_program->get_uniform_location("windowSize");

Outputs/CRT/Internals/Shader.cpp

@@ -38,7 +38,7 @@ GLuint Shader::compile_shader(const char *source, GLenum type)
 	return shader;
 }
 
-Shader::Shader(const char *vertex_shader, const char *fragment_shader)
+Shader::Shader(const char *vertex_shader, const char *fragment_shader, const AttributeBinding *attribute_bindings)
 {
 	_shader_program = glCreateProgram();
 	GLuint vertex = compile_shader(vertex_shader, GL_VERTEX_SHADER);
@@ -46,6 +46,16 @@ Shader::Shader(const char *vertex_shader, const char *fragment_shader)
 
 	glAttachShader(_shader_program, vertex);
 	glAttachShader(_shader_program, fragment);
+
+	if(attribute_bindings)
+	{
+		while(attribute_bindings->name)
+		{
+			glBindAttribLocation(_shader_program, attribute_bindings->index, attribute_bindings->name);
+			attribute_bindings++;
+		}
+	}
+
 	glLinkProgram(_shader_program);
 
 #if defined(DEBUG)
@@ -76,12 +86,12 @@ void Shader::bind()
 	glUseProgram(_shader_program);
 }
 
-GLint Shader::get_attrib_location(const char *name)
+GLint Shader::get_attrib_location(const GLchar *name)
 {
 	return glGetAttribLocation(_shader_program, name);
 }
 
-GLint Shader::get_uniform_location(const char *name)
+GLint Shader::get_uniform_location(const GLchar *name)
 {
 	return glGetUniformLocation(_shader_program, name);
 }

Outputs/CRT/Internals/Shader.hpp

@@ -14,12 +14,38 @@
 namespace OpenGL {
   class Shader {
 	public:
-		Shader(const char *vertex_shader, const char *fragment_shader);
+		struct AttributeBinding {
+			const GLchar *name;
+			GLuint index;
+		};
+
+		/*!
+			Constructs a shader, comprised of:
+			@param vertex_shader The vertex shader source code.
+			@param fragment_shader The fragment shader source code.
+			@param attribute_bindings Either @c nullptr or an array terminated by an entry with a @c nullptr-name of attribute bindings.
+		*/
+		Shader(const char *vertex_shader, const char *fragment_shader, const AttributeBinding *attribute_bindings);
 		~Shader();
 
+		/*!
+			Performs an @c glUseProgram to make this the active shader.
+		*/
 		void bind();
-		GLint get_attrib_location(const char *name);
+
-		GLint get_uniform_location(const char *name);
+		/*!
+			Performs a @c glGetAttribLocation call.
+			@param name The name of the attribute to locate.
+			@returns The location of the requested attribute.
+		*/
+		GLint get_attrib_location(const GLchar *name);
+
+		/*!
+			Performs a @c glGetUniformLocation call.
+			@param name The name of the uniform to locate.
+			@returns The location of the requested uniform.
+		*/
+		GLint get_uniform_location(const GLchar *name);
 
 	private:
 		GLuint compile_shader(const char *source, GLenum type);