mirror of
https://github.com/nunuhara/xsystem4.git
synced 2026-09-26 17:07:55 +03:00
kichikuou
da5ac4a26c
This adds `USE_GLES` compile-time flag. If it's defined, gfx_init() requests an OpenGL ES >=3.0 context. This also makes the following changes to make it work with OpenGL ES: - The USE_GLES flag also switches shader's #version directive, which is now provided separately from the .glsl file. - Implicit conversion between int and float is not supported in GLSL ES. - Use GL_RGB in gfx_copy_main_surface. Because main_surface is in GL_RGB format, using GL_RGBA generates GL_INVALID_OPERATION in OpenGL ES.
38 lines
1.3 KiB
GLSL
38 lines
1.3 KiB
GLSL
/* Copyright (C) 2019 Nunuhara Cabbage <nunuhara@haniwa.technology>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://gnu.org/licenses/>.
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*/
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uniform sampler2D tex;
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uniform vec2 bot_left;
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uniform vec2 top_right;
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in vec2 tex_coord;
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out vec4 frag_color;
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float point_in_rect(vec2 p, vec2 bot_left, vec2 top_right) {
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vec2 s = step(bot_left, p) - step(top_right, p);
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return s.x * s.y;
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}
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void main() {
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vec2 size = vec2(textureSize(tex, 0));
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vec2 tex_bot_left = bot_left / size;
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vec2 tex_top_right = top_right / size;
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vec4 texel = texture(tex, tex_coord);
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float t = point_in_rect(tex_coord, tex_bot_left, tex_top_right);
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frag_color = t * texel + (1.0 - t) * vec4(0, 0, 0, 0);
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}
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