1/*
2 * Copyright (C) 2018 Solarus - http://www.solarus-games.org
3 *
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 3 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program. If not, see <http://www.gnu.org/licenses/>.
16 */
17
18// Scale2X shader adapted from bsnes
19// https://gitorious.org/bsnes/xml-shaders/
20
21#if __VERSION__ >= 130
22#define COMPAT_VARYING out
23#define COMPAT_ATTRIBUTE in
24#define COMPAT_TEXTURE texture
25#else
26#define COMPAT_VARYING varying
27#define COMPAT_ATTRIBUTE attribute
28#define COMPAT_TEXTURE texture2D
29#endif
30
31#ifdef GL_ES
32precision mediump float;
33#define COMPAT_PRECISION mediump
34#else
35#define COMPAT_PRECISION
36#endif
37
38COMPAT_ATTRIBUTE vec2 sol_vertex;
39COMPAT_ATTRIBUTE vec2 sol_tex_coord;
40
41uniform vec2 sol_input_size;
42uniform vec2 sol_output_size;
43uniform mat4 sol_mvp_matrix;
44uniform mat3 sol_uv_matrix;
45vec2 sol_texture_size = sol_input_size;
46
47COMPAT_VARYING vec2 tex_coords[5];
48
49void main() {
50    vec2 offsetx;
51    vec2 offsety;
52
53    gl_Position = sol_mvp_matrix * vec4(sol_vertex, 0, 1);
54
55    offsetx.x = 1.0 / sol_texture_size.x;
56    offsetx.y = 0.0;
57    offsety.y = 1.0 / sol_texture_size.y;
58    offsety.x = 0.0;
59
60    tex_coords[0] = vec2(sol_uv_matrix * vec3(sol_tex_coord, 1));  // center
61    tex_coords[1] = tex_coords[0] - offsetx;  // left
62    tex_coords[2] = tex_coords[0] + offsetx;  // right
63    tex_coords[3] = tex_coords[0] - offsety;  // top
64    tex_coords[4] = tex_coords[0] + offsety;  // bottom
65}
66