Fix T46030: Strange behavior of Cycles Brick Texture

Added some extra seed to the hash, so it's now less likely to give repetitive
patters at values around zero.

This will change distribution of bricks for existing files. but it's something
inevitable.

2 files changed, 2 insertions, 0 deletions

diff --git a/intern/cycles/kernel/shaders/node_brick_texture.osl b/intern/cycles/kernel/shaders/node_brick_texture.osl
index e26e8dbff2c..35e01178ba8 100644
--- a/intern/cycles/kernel/shaders/node_brick_texture.osl
+++ b/intern/cycles/kernel/shaders/node_brick_texture.osl
@@ -22,6 +22,7 @@
 float brick_noise(int n) /* fast integer noise */
 {
 	int nn;
+	n = (n + 1013) & 2147483647;
 	n = (n >> 13) ^ n;
 	nn = (n * (n * n * 60493 + 19990303) + 1376312589) & 2147483647;
 	return 0.5 * ((float)nn / 1073741824.0);
diff --git a/intern/cycles/kernel/svm/svm_brick.h b/intern/cycles/kernel/svm/svm_brick.h
index fcf8f47b77e..9b0cf5ab8c4 100644
--- a/intern/cycles/kernel/svm/svm_brick.h
+++ b/intern/cycles/kernel/svm/svm_brick.h
@@ -21,6 +21,7 @@ CCL_NAMESPACE_BEGIN
 ccl_device_noinline float brick_noise(int n) /* fast integer noise */
 {
 	int nn;
+	n = (n + 1013) & 0x7fffffff;
 	n = (n >> 13) ^ n;
 	nn = (n * (n * n * 60493 + 19990303) + 1376312589) & 0x7fffffff;
 	return 0.5f * ((float)nn / 1073741824.0f);