Eevee: SSR: Add roughness random rays.

source/blender/draw/engines/eevee/shaders/bsdf_sampling_lib.glsl

@@ -6,11 +6,14 @@ uniform float invSampleCount;
 
 vec2 jitternoise = vec2(0.0);
 
+#ifdef NOISE_SIZE
 void setup_noise(void)
 {
 	jitternoise = texture(texJitter, gl_FragCoord.xy / NOISE_SIZE).rg; /* Global variable */
 }
+#endif
 
+#ifdef HAMMERSLEY_SIZE
 vec3 hammersley_3d(float i, float invsamplenbr)
 {
 	vec3 Xi; /* Theta, cos(Phi), sin(Phi) */
@@ -29,6 +32,7 @@ vec3 hammersley_3d(float i)
 {
 	return hammersley_3d(i, invSampleCount);
 }
+#endif
 
 /* -------------- BSDFS -------------- */
 
@@ -42,22 +46,26 @@ float pdf_hemisphere()
 	return 0.5 * M_1_PI;
 }
 
-vec3 sample_ggx(float nsample, float a2, vec3 N, vec3 T, vec3 B)
+vec3 sample_ggx(vec3 rand, float a2, vec3 N, vec3 T, vec3 B)
 {
-	vec3 Xi = hammersley_3d(nsample);
-
 	/* Theta is the aperture angle of the cone */
-	float z = sqrt( (1.0 - Xi.x) / ( 1.0 + a2 * Xi.x - Xi.x ) ); /* cos theta */
+	float z = sqrt( (1.0 - rand.x) / ( 1.0 + a2 * rand.x - rand.x ) ); /* cos theta */
 	float r = sqrt( 1.0 - z * z ); /* sin theta */
-	float x = r * Xi.y;
-	float y = r * Xi.z;
+	float x = r * rand.y;
+	float y = r * rand.z;
 
 	/* Microfacet Normal */
 	vec3 Ht = vec3(x, y, z);
-
 	return tangent_to_world(Ht, N, T, B);
 }
 
+#ifdef HAMMERSLEY_SIZE
+vec3 sample_ggx(float nsample, float a2, vec3 N, vec3 T, vec3 B)
+{
+	vec3 Xi = hammersley_3d(nsample);
+	return sample_ggx(Xi, a2, N, T, B);
+}
+
 vec3 sample_hemisphere(float nsample, vec3 N, vec3 T, vec3 B)
 {
 	vec3 Xi = hammersley_3d(nsample);
@@ -70,4 +78,5 @@ vec3 sample_hemisphere(float nsample, vec3 N, vec3 T, vec3 B)
 	vec3 Ht = vec3(x, y, z);
 
 	return tangent_to_world(Ht, N, T, B);
-}
+}
+#endif