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, 12 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_studiolight.h b/source/blender/blenkernel/BKE_studiolight.h
index d6fff528348..108e93d9caa 100644
--- a/source/blender/blenkernel/BKE_studiolight.h
+++ b/source/blender/blenkernel/BKE_studiolight.h
@@ -87,6 +87,11 @@ enum StudioLightFlag {
   STUDIOLIGHT_RADIANCE_BUFFERS_CALCULATED = (1 << 11),
   STUDIOLIGHT_USER_DEFINED = (1 << 12),
   STUDIOLIGHT_UI_EXPANDED = (1 << 13),
+
+  STUDIOLIGHT_MATCAP_DIFFUSE_GPUTEXTURE = (1 << 14),
+  STUDIOLIGHT_MATCAP_SPECULAR_GPUTEXTURE = (1 << 15),
+  /* Is set for studio lights and matcaps with specular highlight pass. */
+  STUDIOLIGHT_SPECULAR_HIGHLIGHT_PASS = (1 << 16),
 };
 
 #define STUDIOLIGHT_FLAG_ALL (STUDIOLIGHT_INTERNAL | STUDIOLIGHT_EXTERNAL_FILE)
@@ -97,6 +102,11 @@ enum StudioLightFlag {
 
 typedef void StudioLightFreeFunction(struct StudioLight *, void *data);
 
+typedef struct StudioLightImage {
+  ImBuf *ibuf;
+  struct GPUTexture *gputexture;
+} StudioLightImage;
+
 typedef struct StudioLight {
   struct StudioLight *next, *prev;
 
@@ -112,6 +122,8 @@ typedef struct StudioLight {
   int icon_id_matcap_flipped;
   float spherical_harmonics_coefs[STUDIOLIGHT_SH_EFFECTIVE_COEFS_LEN][3];
   float light_direction[3];
+  StudioLightImage matcap_diffuse;
+  StudioLightImage matcap_specular;
   ImBuf *equirect_radiance_buffer;
   ImBuf *equirect_irradiance_buffer;
   ImBuf *radiance_cubemap_buffers[6];