add helper functions for GL type sizes

src/shader.cpp

@@ -26,6 +26,7 @@ bool compileAndLinkShader(shader_program* shader,
 	const char* frag_src,
 	GLuint& vs_id,
 	GLuint& fs_id);
+u32 getGLTypeSize(GLenum e);
 
 
 // NOTE: interface
@@ -310,15 +311,28 @@ dumpTextFile(const char* filepath)
 	return s;
 }
 
+u32
+getGLTypeSize(GLenum e)
+{
+	switch (e) {
+		case GL_FLOAT_VEC3: return 3 * sizeof(GLfloat);
+		case GL_FLOAT_VEC4: return 4 * sizeof(GLfloat);
+		case GL_FLOAT_MAT4: return 16 * sizeof(GLfloat);
+		default:
+			printf("%s(), unknown GLenum\n", __FUNCTION__);
+			return 0;
+	}
+}
+
 // NOTE: returns sizes based on GLSL layout std140
 // 	https://www.khronos.org/opengl/wiki/Interface_Block_(GLSL)#Memory_layout
 u32
-getGLTypeSize(GLenum e)
+getGLTypeSizeStd140(GLenum e)
 {
 	switch (e) {
-		case 0x8b51: return 4 * sizeof(GLfloat);	// GL_FLOAT_VEC3
-		case 0x8b52: return 4 * sizeof(GLfloat);	// GL_FLOAT_VEC4
-		case 0x8b5c: return 16 * sizeof(GLfloat);	// GL_FLOAT_MAT4
+		case GL_FLOAT_VEC3: return 4 * sizeof(GLfloat);
+		case GL_FLOAT_VEC4: return 4 * sizeof(GLfloat);
+		case GL_FLOAT_MAT4: return 16 * sizeof(GLfloat);
 		default:
 			printf("%s(), unknown GLenum\n", __FUNCTION__);
 			return 0;
@@ -476,6 +490,17 @@ getNumAttribComponents(GLenum type)
 	}
 }
 
+GLenum
+getAttribComponentType(GLenum type)
+{
+	switch (type) {
+		case GL_FLOAT_VEC3: return GL_FLOAT;
+		default:
+			printf("%s(), unknown GLenum\n", __FUNCTION__);
+			return 0;
+	}
+}
+
 bool
 parseAttributes(memory_arena* arena, shader_program* s, GLContext* gl_ctx)
 {
@@ -507,6 +532,8 @@ parseAttributes(memory_arena* arena, shader_program* s, GLContext* gl_ctx)
 		attrib->location = location;
 		attrib->num_components = getNumAttribComponents(type);
 		assert(attrib->num_components > 0);
+		attrib->component_type = getAttribComponentType(type);
+		assert(attrib->component_type > 0);
 		attrib->name = arenaCopyCStr(arena, attrib_name, sizeof(attrib_name));
 		// TODO: replace POSITION, NORMAL, UV... etc enums in loadGLMesh()
 		// 	with extra logic to detect mesh to shader mapping