#include <GL/glew.h>

#include "mesh.h"

void mesh_init(Mesh *mesh, int vertex_count)
{
	glGenVertexArrays(1, &mesh->vao);
	mesh->vbos_count = 0;
	mesh->vertex_count = vertex_count;
	glBindVertexArray(mesh->vao);
}

static void mesh_store(Mesh *mesh, void *data, int len, int dimensions, GLenum type)
{
	GLuint vbo;
	GLint index = mesh->vbos_count;
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, len, data, GL_STATIC_DRAW);
	glEnableVertexAttribArray(index);
	if (type == GL_FLOAT)
		glVertexAttribPointer(index, dimensions, type, GL_FALSE, 0, 0);
	else
		glVertexAttribIPointer(index, dimensions, type, 0, 0);
	mesh->vbos[mesh->vbos_count++] = vbo;
}

void mesh_storef(Mesh *mesh, float *data, int count, int dimensions)
{
	mesh_store(mesh, data, count * sizeof(float), dimensions, GL_FLOAT);
}

void mesh_storei(Mesh *mesh, int *data, int count, int dimensions)
{
	mesh_store(mesh, data, count * sizeof(int), dimensions, GL_INT);
}

void mesh_storeu(Mesh *mesh, unsigned int *data, int count, int dimensions)
{
	mesh_store(mesh, data, count * sizeof(unsigned int), dimensions, GL_UNSIGNED_INT);
}

void mesh_storeb(Mesh *mesh, unsigned char *data, int count, int dimensions)
{
	mesh_store(mesh, data, count * sizeof(unsigned char), dimensions, GL_UNSIGNED_BYTE);
}

void mesh_finish(void)
{
	glBindVertexArray(0);
}

void mesh_bind(Mesh *mesh)
{
	glBindVertexArray(mesh->vao);
	for (int i = 0; i < mesh->vbos_count; i++)
		glEnableVertexAttribArray(i);
}

void mesh_unbind(Mesh *mesh)
{
	for (int i = 0; i < mesh->vbos_count; i++)
		glDisableVertexAttribArray(i);
	glBindVertexArray(0);
}

void mesh_draw(Mesh *mesh)
{
	glDrawArrays(GL_TRIANGLES, 0, mesh->vertex_count);
}

void mesh_draw_instanced(Mesh *mesh, int count)
{
	glDrawArraysInstanced(GL_TRIANGLES, 0, mesh->vertex_count, count);
}

void mesh_free(Mesh *mesh)
{
	glDeleteBuffers(mesh->vbos_count, mesh->vbos);
	glDeleteVertexArrays(1, &mesh->vao);
}

void uniform_init(Uniform *uniform, void *data, int len)
{
	glGenBuffers(1, &uniform->id);
	glBindBuffer(GL_UNIFORM_BUFFER, uniform->id);
	glBufferData(GL_UNIFORM_BUFFER, len, data, GL_STATIC_DRAW);
	glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

void uniform_free(Uniform *uniform)
{
	glDeleteBuffers(1, &uniform->id);
}