#pragma once

#include <GL/gl3w.h>

#include "entity.h"
//#include "hexgame.h"
#include "util.h"

struct Entity;


// TODO: can these structs be used as opaque pointers?
struct gl_buffer
{
	GLuint buffer_id = 0;
	size_t buffer_len = 0; // NOTE: number of elements in buffer
	GLfloat* buffer = nullptr;
};

struct gl_index_buffer
{
	GLuint buffer_id = 0;
	size_t buffer_len = 0;
	uint* buffer = nullptr;
};

struct render_object
{
	gl_buffer vertex_buffer;
	gl_buffer normal_buffer;
	gl_buffer color_buffer;
	gl_index_buffer index_buffer;
};

struct rg_shader_program
{
	GLuint program_id = 0;
	GLuint model_matrix_id = 0;
	GLuint view_matrix_id = 0;
	GLuint projection_matrix_id = 0;
	GLuint normal_matrix_id = 0;
	GLuint vertex_array_id = 0;
};

struct render_group
{
	uint num_objects = 0;
	render_object** render_objects = nullptr;
	rg_shader_program shader;
	bool use_normals = false;
	bool draw_indexed = false;
	GLenum draw_mode = GL_TRIANGLES;
};

bool rgInitShaderProgram(rg_shader_program& sp, const char * vertex_code, const char * frag_code);

bool rgInitEntity(Entity* e);

// TODO: fix this function to use just buffers instead of hexes
//void rgFillColorBuffer(GLfloat buf[], int len, std::vector<hex_info>* hexes);

void rgDraw(render_group* rg, glm::mat4 model_matrix,
		glm::mat4 view_matrix, glm::mat4 projection_matrix,
		glm::vec3 light_position, GLuint light_id, bool update_vertex_data = false);

void rgFree(render_group* rg);