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Nunuhara Cabbage
35a84ba708
Used in Shaman's Sanctuary. This implementation gives a bit of a different result compared to SACT2.dll, but it's reasonably close.
71 lines
2.4 KiB
GLSL
71 lines
2.4 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; // the new scene
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uniform sampler2D old; // the old scene
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uniform vec2 resolution; // the screen resolution
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uniform float progress; // effect progress (0..1)
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in vec2 tex_coord;
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out vec4 frag_color;
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const float PI = 3.14159265;
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const vec2 tex_offset = vec2(1.0, 1.0);
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const float sigma = 50.0;
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vec3 get_pixel(vec2 xy) {
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return mix(texture(old, xy).rgb, texture(tex, xy).rgb, progress);
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}
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// incremental gaussian blur algorithm
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void main() {
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vec2 p = tex_coord * resolution;
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float blur_size = (1.0 - abs(progress * 2.0 - 1.0)) * 100.0; // (0..0.5..1) -> (0..50..0)
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float blur_half = blur_size / 2.0;
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vec3 gauss;
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gauss.x = 1.0 / (sqrt(2.0 * PI) * sigma);
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gauss.y = exp(-0.5 / (sigma * sigma));
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gauss.z = gauss.y * gauss.y;
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vec3 avg = vec3(0.0);
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float coefficient_sum = 0.0;
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avg += get_pixel(p / resolution) * gauss.x;
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coefficient_sum += gauss.x;
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gauss.xy *= gauss.yz;
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vec2 tex_offset = vec2(0.25, 0.75);
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for (float i = 1.0; i <= blur_half; i += 2.0) {
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avg += get_pixel((p - i * tex_offset) / resolution) * gauss.x;
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avg += get_pixel((p + i * tex_offset) / resolution) * gauss.x;
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coefficient_sum += 2.0 * gauss.x;
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gauss.xy *= gauss.yz;
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}
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tex_offset = vec2(0.75, 0.25);
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for (float i = 1.0; i <= blur_half; i += 2.0) {
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avg += get_pixel((p - i * tex_offset) / resolution) * gauss.x;
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avg += get_pixel((p + i * tex_offset) / resolution) * gauss.x;
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coefficient_sum += 2.0 * gauss.x;
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gauss.xy *= gauss.yz;
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}
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frag_color = vec4(avg / coefficient_sum, 1.0);
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}
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