71 lines
No EOL
2.5 KiB
GLSL
71 lines
No EOL
2.5 KiB
GLSL
uniform sampler2D tex;
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uniform int operation;
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uniform float width;
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uniform float height;
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#define CORRECTION 2.25
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#define SIZE_ADDITION 3
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vec4 get_texture_at_position(vec2 position) {
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vec2 raw_position = position + vec2(CORRECTION, CORRECTION);
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vec2 raw_uv = raw_position / vec2(width + SIZE_ADDITION, height + SIZE_ADDITION);
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return texture2D(tex, raw_uv);
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}
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vec4 try_get_texture_at_position(vec2 position, inout int count) {
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if (any(greaterThanEqual(position, vec2(width, height))) ||
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any(lessThan(position, vec2(0, 0)))) {
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return vec4(0);
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} else {
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count++;
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return get_texture_at_position(position);
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}
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}
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ivec2 get_corrected_position() {
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vec2 raw_uv = cogl_tex_coord0_in.st;
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vec2 raw_position = raw_uv * vec2(width + SIZE_ADDITION, height + SIZE_ADDITION);
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return ivec2(raw_position - vec2(CORRECTION, CORRECTION));
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}
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void main() {
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ivec2 corrected_position = get_corrected_position();
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// 1-step derivative
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if (operation == 0) {
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vec4 color = vec4(0);
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int c = 0;
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color += try_get_texture_at_position(corrected_position + vec2(0, 1), c);
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color -= try_get_texture_at_position(corrected_position + vec2(0, 0), c);
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color += try_get_texture_at_position(corrected_position + vec2(1, 0), c);
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color -= try_get_texture_at_position(corrected_position + vec2(0, 0), c);
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if (c < 4) {
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color = vec4(0);
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}
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cogl_color_out = vec4(color.xyz, 1);
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} else
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// 2-step derivative
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if (operation == 1) {
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vec4 color = vec4(0);
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int c = 0;
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color += try_get_texture_at_position(corrected_position + vec2(0, 1), c);
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color -= try_get_texture_at_position(corrected_position + vec2(0, -1), c);
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color += try_get_texture_at_position(corrected_position + vec2(1, 0), c);
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color -= try_get_texture_at_position(corrected_position + vec2(-1, 0), c);
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if (c < 4) {
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color = vec4(0);
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}
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cogl_color_out = vec4(color.xyz / 2, 1);
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} else
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// laplacian
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if (operation == 2) {
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vec4 color = vec4(0);
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color = -4 * get_texture_at_position(corrected_position);
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color += get_texture_at_position(corrected_position + vec2(0, 1));
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color += get_texture_at_position(corrected_position + vec2(0, -1));
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color += get_texture_at_position(corrected_position + vec2(1, 0));
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color += get_texture_at_position(corrected_position + vec2(-1, 0));
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cogl_color_out = vec4(color.xyz, 1);
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}
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} |