Cycles: Implement camera zoom motion blur

Works totally similar to camera motion blur and majority of the changes are
related on just passing extra arguments to sync() functions.

Couple of things still to look into:

- Motion pass will not include motion caused by the zoom.
- Only perspective cameras are supported currently.
- Motion is being interpolated on projected coordinates, which might give
  different results from constructing projection matrix from interpolated
  field of view.

  This could be good enough for us, but we need to consider improving this
  at some point.

Reviewers: juicyfruit, dingto

Reviewed By: dingto

Differential Revision: https://developer.blender.org/D1383

1 files changed, 5 insertions, 0 deletions

diff --git a/intern/cycles/util/util_transform.h b/intern/cycles/util/util_transform.h
index 0b87db0a379..ba8d04b5c16 100644
--- a/intern/cycles/util/util_transform.h
+++ b/intern/cycles/util/util_transform.h
@@ -55,6 +55,11 @@ typedef struct DecompMotionTransform {
 	float4 post_x, post_y;
 } DecompMotionTransform;
 
+typedef struct PerspectiveMotionTransform {
+	Transform pre;
+	Transform post;
+} PerspectiveMotionTransform;
+
 /* Functions */
 
 ccl_device_inline float3 transform_perspective(const Transform *t, const float3 a)