libTangerine/include/shader_program.h

#pragma once

#include <GL/glew.h>

#include "types.h"


// TODO: implement a 'cavity' effect for the default shader
// 	https://blender.community/c/rightclickselect/J9bbbc/
// 	https://developer.blender.org/rBf1fd5ed74fb0afd602f53860d0b2db46189c218a
// 	https://developer.blender.org/diffusion/B/browse/master/source/blender/draw/engines/workbench/shaders/workbench_cavity_lib.glsl
// 	https://www.casual-effects.com/research/McGuire2011AlchemyAO/VV11AlchemyAO.pdf
// 	https://github.com/evanw/madebyevan.com/blob/master/src/templates/shaders-curvature.jade
struct default_shader_program
{
	GLuint program_id;

	GLuint model_matrix_id;
	GLuint world_transform_id;
	GLuint view_matrix_id;
	GLuint projection_matrix_id;
	GLuint normal_matrix_id;

	GLuint vertex_array_id;
	GLuint sampler_id;
	GLuint num_lights_id;
};

struct simple_shader_program
{
	GLuint program_id;
	GLuint world_transform_id;
	GLuint MVP_id;
	GLuint vertex_array_id;
};

struct shader_wrapper
{
	shader_t shader_type;
	default_shader_program* default_shader;
	simple_shader_program* simple_shader;
};


// TODO: find a way to initialize different shaders with different
// 	uniform layouts with a single function
//	look at using uniform blocks and retrieving locations with
//	glGetUniformBlockIndex() and their size with glGetActiveUniformBlockiv()
//	see chapter 2 in the red book
simple_shader_program*
shaderInitSimple(const char* vertex_code, const char* frag_code);

default_shader_program*
shaderInitDefault(const char* vertex_code, const char* frag_code);

void shaderFree(uint program_id);