Multi-View: Cycles - Spherical Stereo support (VR Panoramas)

This is a new option for panorama cameras to render
stereo that can be used in virtual reality devices

The option is available under the camera panel when Multi-View is enabled (Views option in the Render Layers panel)

Known limitations:
------------------
* Parallel convergence is not supported (you need to set a convergence distance really high to simulate this effect).

* Pivot was not supposed to affect the render but it does, this has to be looked at, but for now set it to CENTER

* Derivatives in perspective camera need to be pre-computed or we shuld get rid of kcam->dx/dy (Sergey words, I don't fully grasp the implication shere)

* This works in perspective mode and in panorama mode. However, for fully benefit from this effect in perspective mode you need to render a cube map. (there is an addon for this, developed separately, perhaps we could include it in master).

* We have no support for "neck distance" at the moment. This is supposed to help with objects at short distances.

* We have no support to rotate the "Up Axis" of the stereo plane. Meaning, we hardcode 0,0,1 as UP, and create the stereo pair related to that. (although we could take the camera local UP when rendering panoramas, this wouldn't work for perspective cameras.

* We have no support for interocular distance attenuation based on the proximity of the poles  (which helps to reduce the pole rotation effect/artifact).

THIS NEEDS DOCS - both in 2.78 release log and the Blender manual.
Meanwhile you can read about it here: http://code.blender.org/2015/03/1451

This patch specifically dates from March 2015, as you can see in the code.blender.org post. Many thanks to all the reviewers, testers and minor sponsors who helped me maintain spherical-stereo for 1 year.

All that said, have fun with this. This feature was what got me started with Multi-View development (at the time what I was looking for was Fulldome stereo support, but the implementation is the same). In order to make this into Blender I had to make it aiming at a less-specic user-case	 Thus Multi-View started. (this was December 2012, during Siggraph Asia and a chat I had with Paul Bourke during the conference). I don't have the original patch anymore, but you can find a re-based version of it from March 2013, right before I start with the Multi-View project https://developer.blender.org/P332

Reviewers: sergey, dingto

Subscribers: #cycles

Differential Revision: https://developer.blender.org/D1223

1 files changed, 4 insertions, 2 deletions

diff --git a/source/blenderplayer/bad_level_call_stubs/stubs.c b/source/blenderplayer/bad_level_call_stubs/stubs.c
index e96e866245a..bbf0ffa4cd4 100644
--- a/source/blenderplayer/bad_level_call_stubs/stubs.c
+++ b/source/blenderplayer/bad_level_call_stubs/stubs.c
@@ -230,9 +230,11 @@ void RE_texture_rng_init() RET_NONE
 void RE_texture_rng_exit() RET_NONE
 
 bool RE_layers_have_name(struct RenderResult *result) {STUB_ASSERT(0); return 0;}
+const char *RE_engine_active_view_get(struct RenderEngine *engine) RET_NULL
 void RE_engine_active_view_set(struct RenderEngine *engine, const char *viewname) {STUB_ASSERT(0);}
-void RE_engine_get_camera_model_matrix(struct RenderEngine *engine, struct Object *camera, float *r_modelmat) {STUB_ASSERT(0);}
-float RE_engine_get_camera_shift_x(struct RenderEngine *engine, struct Object *camera) RET_ZERO
+void RE_engine_get_camera_model_matrix(struct RenderEngine *engine, struct Object *camera, int use_spherical_stereo, float *r_modelmat) {STUB_ASSERT(0);}
+float RE_engine_get_camera_shift_x(struct RenderEngine *engine, struct Object *camera, int use_spherical_stereo) RET_ZERO
+int RE_engine_get_spherical_stereo(struct RenderEngine *engine, struct Object *camera) RET_ZERO
 void RE_SetActiveRenderView(struct Render *re, const char *viewname) {STUB_ASSERT(0);}
 
 struct RenderPass *RE_pass_find_by_type(volatile struct RenderLayer *rl, int passtype, const char *viewname) RET_NULL