Cycles: support for motion vector and UV passes.

Most of the changes are related to adding support for motion data throughout
the code. There's some code for actual camera/object motion blur raytracing
but it's unfinished (it badly slows down the raytracing kernel even when the
option is turned off), so that code it disabled still.

Motion vector export from Blender tries to avoid computing derived meshes
when the mesh does not have a deforming modifier, and it also won't store
motion vectors for every vertex if only the object or camera is moving.

intern/cycles/kernel/kernel_path.h

@@ -18,8 +18,8 @@
 
 #include "kernel_differential.h"
 #include "kernel_montecarlo.h"
-#include "kernel_triangle.h"
 #include "kernel_object.h"
+#include "kernel_triangle.h"
 #ifdef __QBVH__
 #include "kernel_qbvh.h"
 #else
@@ -324,6 +324,9 @@ __device float4 kernel_path_integrate(KernelGlobals *kg, RNG *rng, int sample, R
 				light_ray.P = ray_offset(sd.P, sd.Ng);
 				light_ray.D = ao_D;
 				light_ray.t = kernel_data.background.ao_distance;
+#ifdef __MOTION__
+				light_ray.time = sd.time;
+#endif
 
 				if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow)) {
 					float3 ao_bsdf = shader_bsdf_diffuse(kg, &sd)*kernel_data.background.ao_factor;
@@ -346,6 +349,10 @@ __device float4 kernel_path_integrate(KernelGlobals *kg, RNG *rng, int sample, R
 				BsdfEval L_light;
 				bool is_lamp;
 
+#ifdef __MOTION__
+				light_ray.time = sd.time;
+#endif
+
 #ifdef __MULTI_LIGHT__
 				/* index -1 means randomly sample from distribution */
 				int i = (kernel_data.integrator.num_distribution)? -1: 0;
@@ -449,7 +456,13 @@ __device void kernel_path_trace(KernelGlobals *kg,
 	float lens_u = path_rng(kg, &rng, sample, PRNG_LENS_U);
 	float lens_v = path_rng(kg, &rng, sample, PRNG_LENS_V);
 
-	camera_sample(kg, x, y, filter_u, filter_v, lens_u, lens_v, &ray);
+#ifdef __MOTION__
+	float time = path_rng(kg, &rng, sample, PRNG_TIME);
+#else
+	float time = 0.0f;
+#endif
+
+	camera_sample(kg, x, y, filter_u, filter_v, lens_u, lens_v, time, &ray);
 
 	/* integrate */
 	float4 L = kernel_path_integrate(kg, &rng, sample, ray, buffer);