[Bf-blender-cvs] [b54447c] master: Cycles: Make sure ray direction is always normalized

[Sergey Sharybin]

Commit: b54447c0eb12d78cd1282db4cb3fb49a9be13b78
Author: Sergey Sharybin
Date:   Fri Oct 9 14:26:23 2015 +0500
Branches: master
https://developer.blender.org/rBb54447c0eb12d78cd1282db4cb3fb49a9be13b78

Cycles: Make sure ray direction is always normalized

Ray direction is assumed to be normalized in such areas as scaling intersection
distance on instance push/pop when doing ray-scene intersection, but it was
possible that some closures wouldn't give normalized direction which could cause
wrong intersection checks.

Now normalization will happen on surface bounce, which could be a bit of a waste
if closure actually gives normalized direction, but currently only transparent
BSDF seems to give guaranteed normalized direction.

===================================================================

M	intern/cycles/kernel/kernel_path_surface.h

===================================================================

diff --git a/intern/cycles/kernel/kernel_path_surface.h b/intern/cycles/kernel/kernel_path_surface.h
index fe85a6b..4485be8 100644
--- a/intern/cycles/kernel/kernel_path_surface.h
+++ b/intern/cycles/kernel/kernel_path_surface.h
@@ -150,7 +150,7 @@ ccl_device bool kernel_branched_path_surface_bounce(KernelGlobals *kg, RNG *rng,
 
 	/* setup ray */
 	ray->P = ray_offset(ccl_fetch(sd, P), (label & LABEL_TRANSMIT)? -ccl_fetch(sd, Ng): ccl_fetch(sd, Ng));
-	ray->D = bsdf_omega_in;
+	ray->D = normalize(bsdf_omega_in);
 	ray->t = FLT_MAX;
 #ifdef __RAY_DIFFERENTIALS__
 	ray->dP = ccl_fetch(sd, dP);
@@ -257,7 +257,7 @@ ccl_device_inline bool kernel_path_surface_bounce(KernelGlobals *kg, ccl_addr_sp
 
 		/* setup ray */
 		ray->P = ray_offset(ccl_fetch(sd, P), (label & LABEL_TRANSMIT)? -ccl_fetch(sd, Ng): ccl_fetch(sd, Ng));
-		ray->D = bsdf_omega_in;
+		ray->D = normalize(bsdf_omega_in);
 
 		if(state->bounce == 0)
 			ray->t -= ccl_fetch(sd, ray_length); /* clipping works through transparent */