Eevee: Perf: Update noises (in utilTex) via GPU drawing.

This leads to a ~3ms improvement of CPU time during drawing.
This prevent the rendering from being stalled waiting for the texture data to be transfered.

1 files changed, 18 insertions, 0 deletions

diff --git a/source/blender/draw/engines/eevee/shaders/update_noise_frag.glsl b/source/blender/draw/engines/eevee/shaders/update_noise_frag.glsl
new file mode 100644
index 00000000000..13ffe02eb0d
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/update_noise_frag.glsl
@@ -0,0 +1,18 @@
+
+uniform sampler2D blueNoise;
+uniform vec3 offsets;
+
+out vec4 FragColor;
+
+#define M_2PI 6.28318530717958647692
+
+void main(void)
+{
+	vec2 blue_noise = texelFetch(blueNoise, ivec2(gl_FragCoord.xy), 0).xy;
+
+	float noise = fract(blue_noise.y + offsets.z);
+	FragColor.x = fract(blue_noise.x + offsets.x);
+	FragColor.y = fract(blue_noise.y + offsets.y);
+	FragColor.z = cos(noise * M_2PI);
+	FragColor.w = sin(noise * M_2PI);
+}