57 lines
1.6 KiB
GLSL
57 lines
1.6 KiB
GLSL
#version 110
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uniform sampler2D u_sampler;
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uniform mat3 u_convolution_matrix;
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uniform vec3 u_viewport_size_alpha;
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uniform vec3 u_picking_color;
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varying vec2 tex_coords;
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vec4 sample(float offsetX, float offsetY)
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{
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return texture2D(u_sampler, vec2(tex_coords.x + offsetX, tex_coords.y + offsetY));
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}
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// see https://docs.gl/sl4/sign
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// glsl 110 & 120 may not support the sign func
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float sign_glsl_110(float value)
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{
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if (value > 1e-6) {
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return 1.0;
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}
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else if (value < -1e-6) {
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return -1.0;
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}
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return 0.0;
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}
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void main()
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{
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vec4 pixels[9];
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float deltaWidth = 1.0 / u_viewport_size_alpha.x;
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float deltaHeight = 1.0 / u_viewport_size_alpha.y;
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float alpha = u_viewport_size_alpha.z;
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float effect_width = 2.0;
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deltaWidth = deltaWidth * effect_width;
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deltaHeight = deltaHeight * effect_width;
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pixels[0] = sample(-deltaWidth, deltaHeight );
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pixels[1] = sample(0.0, deltaHeight );
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pixels[2] = sample(deltaWidth, deltaHeight );
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pixels[3] = sample(-deltaWidth, 0.0);
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pixels[4] = sample(0.0, 0.0);
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pixels[5] = sample(deltaWidth, 0.0);
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pixels[6] = sample(-deltaWidth, -deltaHeight);
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pixels[7] = sample(0.0, -deltaHeight);
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pixels[8] = sample(deltaWidth, -deltaHeight);
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vec4 accumulator = vec4(0.0);
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for (int i = 0; i < 3; i++)
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{
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for (int j = 0; j < 3; ++j)
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{
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accumulator += sign_glsl_110(pixels[3 * i + j].a) * vec4(u_picking_color, 1.0) * u_convolution_matrix[i][j];
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}
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}
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if ((abs(accumulator.a) - alpha * pixels[4].a) * 1e6 > 1.0) {
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accumulator = vec4(u_picking_color, abs(accumulator.a));
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}
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gl_FragColor = accumulator;
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} |