/*
 * Copyright (C) 2018 Tomasz Kramkowski <tk@the-tk.com>
 * SPDX-License-Identifier: MIT
 */
#include <assert.h>
#include <stdio.h>
#include <string.h>

#include "ensize.h"
#include "eprintf.h"
#include "glprog.h"
#include "mtl.h"
#include "tex.h"

struct mtl {
	char name[50];
#define SH_TEX(_, name) GLuint name;
#include "shaders/data.h"
};

static struct mtl *mtls;
static int lmtls;
static size_t nmtls;

// tex_file: Load texture asset from file
GLuint tex_file(const char *name, const char *type)
{
	char loc[100];
	GLuint ret;
	FILE *f;

	snprintf(loc, sizeof loc, "assets/%s.%s.png", name, type);
	f = fopen(loc, "rb");
	if (f == NULL)
		eprintf("Could not open '%s':", loc);
	ret = png2tex(f);
	fclose(f);

	return ret;
}

// mtl_load: Load a set of textures as a material
int mtl_load(char *name)
{
	struct mtl *m;

	for (int i = 0; i < lmtls; i++)
		if (strcmp(mtls[i].name, name) == 0)
			return i;

	mtls = ENSIZE(mtls, lmtls + 1, &nmtls, 16);
	m = &mtls[lmtls];

	snprintf(m->name, sizeof m->name, "%s", name);

#define SH_TEX(_, n) m->n = tex_file(name, #n);
#include "shaders/data.h"

	return lmtls++;
}

// mtl_use: Set OpenGL state to use a certain material index
void mtl_use(int mtl)
{
	assert(mtl < lmtls);
	GLenum texture = GL_TEXTURE0;

	// TODO: Blank textures or something
	if (mtl < 0)
		return;

#define SH_TEX(type, name)				\
	gl_tex_active(texture++);			\
	gl_tex_bind(GL_TEXTURE_##type, mtls[mtl].name);
#include "shaders/data.h"
}