Differential D16789 Diff 58669 source/blender/compositor/realtime_compositor/shaders/compositor_glare_streaks_filter.glsl

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source/blender/compositor/realtime_compositor/shaders/compositor_glare_streaks_filter.glsl

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				#pragma BLENDER_REQUIRE(gpu_shader_compositor_texture_utilities.glsl)

				void main()
				{
				ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
				ivec2 input_size = texture_size(input_streak_tx);

				/* Add 0.5 to evaluate the input sampler at the center of the pixel and divide by the image size
				* to get the coordinates into the sampler's expected [0, 1] range. Similarly, transform the
				* vector into the sampler's space by dividing by the input size. */
				vec2 coordinates = (vec2(texel) + vec2(0.5)) / input_size;
				vec2 vector = streak_vector / input_size;

				/* Load three equally spaced neighbours to the current pixel in the direction of the streak
				* vector. */
				vec4 neighbours[3];
				neighbours[0] = texture(input_streak_tx, coordinates + vector);
				neighbours[1] = texture(input_streak_tx, coordinates + vector * 2.0);
				neighbours[2] = texture(input_streak_tx, coordinates + vector * 3.0);

				/* Attenuate the value of two of the channels for each of the neighbours by multiplying by the
				* color modulator. The particular channels for each neighbour were chosen to be visually similar
				* to the modulation pattern of chromatic aberration. */
				neighbours[0].gb *= color_modulator;
				neighbours[1].rg *= color_modulator;
				neighbours[2].rb *= color_modulator;

				/* Compute the weighted sum of all neighbours using the given fade factors as weights. The
				* weights are expected to be lower for neighbours that are further away. */
				vec4 weighted_neighbours_sum = vec4(0.0);
				for (int i = 0; i < 3; i++) {
				weighted_neighbours_sum += fade_factors[i] * neighbours[i];
				}

				/* The output is the average between the center color and the weighted sum of the neighbours.
				* Which intuitively mean that highlights will spread in the direction of the streak, which is
				* the desired result. */
				vec4 center_color = texture(input_streak_tx, coordinates);
				vec4 output_color = (center_color + weighted_neighbours_sum) / 2.0;
				imageStore(output_streak_img, texel, output_color);
				}