Matcap support in 3D Viewport.

Full log is here:
http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.66/Usability#Matcap_in_3D_viewport

Implementation notes:

- Matcaps are an extension of Solid draw mode, and don't show in other drawmodes.
  (It's mostly intended to aid modeling/sculpt)

- By design, Matcaps are a UI feature, and only stored locally for the UI itself, and
  won't affect rendering or materials.

- Currently a set of 16 (GPL licensed) Matcaps have been compiled into Blender. 
  It doesn't take memory or cpu time, until you use it.

- Brush Icons and Matcaps use same code now, and only get generated/allocated on
  actually using it (instead of on startup).

- The current set might get new or different images still, based on user feedback.

- Matcap images are 512x512 pixels, so each image takes 1 Mb memory. Unused matcaps get 
  freed immediately. The Matcap icon previews (128x128 pixels) stay in memory.

- Loading own matcap image files will be added later. That needs design and code work 
  to get it stable and memory-friendly.

- The GLSL code uses the ID PreviewImage for matcaps. I tested it using the existing
  Material previews, which has its limits... especially for textured previews the
  normal-mapped matcap won't look good.

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/gpu/GPU_material.h b/source/blender/gpu/GPU_material.h
index 22cfdab6043..17d3ce3cd73 100644
--- a/source/blender/gpu/GPU_material.h
+++ b/source/blender/gpu/GPU_material.h
@@ -54,6 +54,7 @@ struct GPUNodeStack;
 struct GPUMaterial;
 struct GPUTexture;
 struct GPULamp;
+struct PreviewImage;
 
 typedef struct GPUNode GPUNode;
 typedef struct GPUNodeLink GPUNodeLink;
@@ -108,6 +109,7 @@ GPUNodeLink *GPU_attribute(int type, const char *name);
 GPUNodeLink *GPU_uniform(float *num);
 GPUNodeLink *GPU_dynamic_uniform(float *num, int dynamictype, void *data);
 GPUNodeLink *GPU_image(struct Image *ima, struct ImageUser *iuser, int isdata);
+GPUNodeLink *GPU_image_preview(struct PreviewImage *prv);
 GPUNodeLink *GPU_texture(int size, float *pixels);
 GPUNodeLink *GPU_dynamic_texture(struct GPUTexture *tex, int dynamictype, void *data);
 GPUNodeLink *GPU_builtin(GPUBuiltin builtin);
@@ -122,6 +124,7 @@ GPUBlendMode GPU_material_alpha_blend(GPUMaterial *material, float obcol[4]);
 /* High level functions to create and use GPU materials */
 
 GPUMaterial *GPU_material_from_blender(struct Scene *scene, struct Material *ma);
+GPUMaterial *GPU_material_matcap(struct Scene *scene, struct Material *ma);
 void GPU_material_free(struct Material *ma);
 
 void GPU_materials_free(void);