Merge pull request #50644 from BastiaanOlij/mobile_compute_to_fragment

1 files changed, 74 insertions, 0 deletions

diff --git a/servers/rendering/renderer_rd/shaders/luminance_reduce_raster.glsl b/servers/rendering/renderer_rd/shaders/luminance_reduce_raster.glsl
new file mode 100644
index 0000000000..29ebd74a90
--- /dev/null
+++ b/servers/rendering/renderer_rd/shaders/luminance_reduce_raster.glsl
@@ -0,0 +1,74 @@
+/* clang-format off */
+#[vertex]
+
+#version 450
+
+#VERSION_DEFINES
+
+#include "luminance_reduce_raster_inc.glsl"
+
+layout(location = 0) out vec2 uv_interp;
+/* clang-format on */
+
+void main() {
+	vec2 base_arr[4] = vec2[](vec2(0.0, 0.0), vec2(0.0, 1.0), vec2(1.0, 1.0), vec2(1.0, 0.0));
+	uv_interp = base_arr[gl_VertexIndex];
+
+	gl_Position = vec4(uv_interp * 2.0 - 1.0, 0.0, 1.0);
+}
+
+/* clang-format off */
+#[fragment]
+
+#version 450
+
+#VERSION_DEFINES
+
+#include "luminance_reduce_raster_inc.glsl"
+
+layout(location = 0) in vec2 uv_interp;
+/* clang-format on */
+
+layout(set = 0, binding = 0) uniform sampler2D source_exposure;
+
+#ifdef FINAL_PASS
+layout(set = 1, binding = 0) uniform sampler2D prev_luminance;
+#endif
+
+layout(location = 0) out highp float luminance;
+
+void main() {
+	ivec2 dest_pos = ivec2(uv_interp * settings.dest_size);
+	ivec2 src_pos = ivec2(uv_interp * settings.source_size);
+
+	ivec2 next_pos = (dest_pos + ivec2(1)) * settings.source_size / settings.dest_size;
+	next_pos = max(next_pos, src_pos + ivec2(1)); //so it at least reads one pixel
+
+	highp vec3 source_color = vec3(0.0);
+	for (int i = src_pos.x; i < next_pos.x; i++) {
+		for (int j = src_pos.y; j < next_pos.y; j++) {
+			source_color += texelFetch(source_exposure, ivec2(i, j), 0).rgb;
+		}
+	}
+
+	source_color /= float((next_pos.x - src_pos.x) * (next_pos.y - src_pos.y));
+
+#ifdef FIRST_PASS
+	luminance = max(source_color.r, max(source_color.g, source_color.b));
+
+	// This formula should be more "accurate" but gave an overexposed result when testing.
+	// Leaving it here so we can revisit it if we want.
+	// luminance = source_color.r * 0.21 + source_color.g * 0.71 + source_color.b * 0.07;
+#else
+	luminance = source_color.r;
+#endif
+
+#ifdef FINAL_PASS
+	// Obtain our target luminance
+	luminance = clamp(luminance, settings.min_luminance, settings.max_luminance);
+
+	// Now smooth to our transition
+	highp float prev_lum = texelFetch(prev_luminance, ivec2(0, 0), 0).r; //1 pixel previous luminance
+	luminance = prev_lum + (luminance - prev_lum) * clamp(settings.exposure_adjust, 0.0, 1.0);
+#endif
+}