Workbench: Specular Highlighting for MatCaps

With Blender 2.80 we introduced a more flexible matcap system. One
change we did was to multiply the matcap with the base color that was
shaded. As matcaps contains diffuse and specular lighting in a single
texture this lead to rendering artifacts. Artists were complaining that
everything looked to metalic.

We now support a separate `diffuse` and `specular` pass for matcaps.

`shaded_color = diffuse_light * base_color + specular_light`

For matcaps to support this feature they need to be multilayer openexr
files with 2 renderpasses (named `diffuse` and `specular`). In the future
we can change this to first pass/second pass in stead of this naming
convention.

Reviewed By: fclem, brecht

Differential Revision: https://developer.blender.org/D5335

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/imbuf/intern/allocimbuf.c b/source/blender/imbuf/intern/allocimbuf.c
index 7d2f51af65e..75db3fd3c73 100644
--- a/source/blender/imbuf/intern/allocimbuf.c
+++ b/source/blender/imbuf/intern/allocimbuf.c
@@ -428,7 +428,8 @@ bool imb_addrectImBuf(ImBuf *ibuf)
 struct ImBuf *IMB_allocFromBuffer(const unsigned int *rect,
                                   const float *rectf,
                                   unsigned int w,
-                                  unsigned int h)
+                                  unsigned int h,
+                                  unsigned int channels)
 {
   ImBuf *ibuf = NULL;
 
@@ -438,6 +439,7 @@ struct ImBuf *IMB_allocFromBuffer(const unsigned int *rect,
 
   ibuf = IMB_allocImBuf(w, h, 32, 0);
 
+  ibuf->channels = channels;
   if (rectf) {
     ibuf->rect_float = MEM_dupallocN(rectf);
     ibuf->flags |= IB_rectfloat;