Omar Emara
7d4aa0db9e
This patch implements the despeckle node for the realtime compositor. Differential Revision: https://developer.blender.org/D15673 Reviewed By: Clement Foucault
71 lines
3.0 KiB
GLSL
71 lines
3.0 KiB
GLSL
#pragma BLENDER_REQUIRE(gpu_shader_compositor_texture_utilities.glsl)
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/* Returns true if the given color is close enough to the given reference color within the
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* threshold supplied by the user, and returns false otherwise. */
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bool is_close(vec4 reference_color, vec4 color)
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{
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return all(lessThan(abs(reference_color - color).rgb, vec3(threshold)));
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}
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void main()
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{
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ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
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/* A 3x3 weights kernel whose weights are the inverse of the distance to the center of the
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* kernel. So the center weight is zero, the corners weights are (1 / sqrt(2)), and the rest
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* of the weights are 1. The total sum of weights is 4 plus quadruple the corner weight. */
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float corner_weight = 1.0 / sqrt(2.0);
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float sum_of_weights = 4.0 + corner_weight * 4.0;
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mat3 weights = mat3(vec3(corner_weight, 1.0, corner_weight),
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vec3(1.0, 0.0, 1.0),
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vec3(corner_weight, 1.0, corner_weight));
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vec4 center_color = texture_load(input_tx, texel);
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/* Go over the pixels in the 3x3 window around the center pixel and compute the total sum of
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* their colors multiplied by their weights. Additionally, for pixels whose colors are not close
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* enough to the color of the center pixel, accumulate their color as well as their weights. */
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vec4 sum_of_colors = vec4(0);
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float accumulated_weight = 0.0;
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vec4 accumulated_color = vec4(0);
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for (int j = 0; j < 3; j++) {
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for (int i = 0; i < 3; i++) {
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float weight = weights[j][i];
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vec4 color = texture_load(input_tx, texel + ivec2(i - 1, j - 1)) * weight;
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sum_of_colors += color;
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if (!is_close(center_color, color)) {
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accumulated_color += color;
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accumulated_weight += weight;
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}
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}
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}
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/* If the accumulated weight is zero, that means all pixels in the 3x3 window are similar and no
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* need to despeckle anything, so write the original center color and return. */
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if (accumulated_weight == 0.0) {
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imageStore(output_img, texel, center_color);
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return;
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}
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/* If the ratio between the accumulated weights and the total sum of weights is not larger than
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* the user specified neighbor threshold, then the number of pixels in the neighborhood that are
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* not close enough to the center pixel is low, and no need to despeckle anything, so write the
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* original center color and return. */
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if (accumulated_weight / sum_of_weights < neighbor_threshold) {
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imageStore(output_img, texel, center_color);
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return;
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}
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/* If the weighted average color of the neighborhood is close enough to the center pixel, then no
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* need to despeckle anything, so write the original center color and return. */
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if (is_close(center_color, sum_of_colors / sum_of_weights)) {
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imageStore(output_img, texel, center_color);
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return;
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}
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/* We need to despeckle, so write the mean accumulated color. */
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float factor = texture_load(factor_tx, texel).x;
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vec4 mean_color = accumulated_color / accumulated_weight;
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imageStore(output_img, texel, mix(center_color, mean_color, factor));
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}
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