Bake API - bpy.ops.object.bake()

New operator that can calls a bake function to the current render engine when available. This commit provides no feature for the users, but allows external engines to be accessed by the operator and be integrated with the baking api.

The API itself is simple. Blender sends a populated array of BakePixels to the renderer, and gets back an array of floats with the result.

The Blender Internal (and multires) system is still running independent, but we eventually will pipe it through the API as well. Cycles baking will come next as a separated commit

Python Operator:
----------------
The operator can be called with some arguments, or a user interface can be created for it. In that case the arguments can be ommited and the interface can expose the settings from bpy.context.scene.render.bake

bpy.ops.object.bake(type='COMBINED', filepath="", width=512, height=512, margin=16, use_selected_to_active=False, cage_extrusion=0, cage="", normal_space='TANGENT', normal_r='POS_X', normal_g='POS_Y', normal_b='POS_Z', save_mode='INTERNAL', use_clear=False, use_split_materials=False, use_automatic_name=False)
Note: external save mode is currently disabled.

Supported Features:
------------------
 * Margin - Baked result is extended this many pixels beyond the border of each UV "island," to soften seams in the texture.

 * Selected to Active - bake shading on the surface of selected object to the active object. The rays are cast from the lowpoly object inwards towards the highpoly object. If the highpoly object is not entirely involved by the lowpoly object, you can tweak the rays start point with Cage Extrusion. For even more control of the cage you can use a Cage object.

 * Cage Extrusion - distance to use for the inward ray cast when using selected to active

 * Custom Cage - object to use as cage (instead of the lowpoly object).

 * Normal swizzle - change the axis that gets mapped to RGB

 * Normal space - save as tangent or object normal spaces

Supported Passes:
-----------------
Any pass that is supported by Blender renderlayer system. Though it's up to the external engine to provide a valid enum with its supported passes. Normal passes get a special treatment since we post-process them to converted and "swizzled"

Development Notes for External Engines:
---------------------------------------
(read them in bake_api.c)

* For a complete implementation example look at the Cycles Bake commit (next).

Review: D421
Reviewed by: Campbell Barton, Brecht van Lommel, Sergey Sharybin, Thomas Dinge

Normal map pipeline "consulting" by Andy Davies (metalliandy)
Original design by Brecht van Lommel.

The entire commit history can be found on the branch: bake-cycles

2 files changed, 109 insertions, 0 deletions

diff --git a/source/blender/render/extern/include/RE_bake.h b/source/blender/render/extern/include/RE_bake.h
new file mode 100644
index 00000000000..d59819c8ef4
--- /dev/null
+++ b/source/blender/render/extern/include/RE_bake.h
@@ -0,0 +1,105 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version. 
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2010 Blender Foundation.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s):
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file RE_bake.h
+ *  \ingroup render
+ */
+
+#ifndef __RE_BAKE_H__
+#define __RE_BAKE_H__
+
+struct Render;
+struct Mesh;
+
+typedef struct BakeImage {
+	struct Image *image;
+	int width;
+	int height;
+	int offset;
+} BakeImage;
+
+typedef struct BakeImages {
+	BakeImage *data; /* all the images of an object */
+	int *lookup;     /* lookup table from Material to BakeImage */
+	int size;
+} BakeImages;
+
+typedef struct BakePixel {
+	int primitive_id;
+	float uv[2];
+	float du_dx, du_dy;
+	float dv_dx, dv_dy;
+} BakePixel;
+
+typedef struct BakeHighPolyData {
+	struct BakePixel *pixel_array;
+	struct Object *ob;
+	struct ModifierData *tri_mod;
+	struct Mesh *me;
+	char restrict_flag;
+	float mat_lowtohigh[4][4];
+} BakeHighPolyData;
+
+/* external_engine.c */
+bool RE_bake_has_engine(struct Render *re);
+
+bool RE_bake_engine(
+        struct Render *re, struct Object *object, const BakePixel pixel_array[],
+        const int num_pixels, const int depth, const ScenePassType pass_type, float result[]);
+
+/* bake.c */
+int RE_pass_depth(const ScenePassType pass_type);
+bool RE_bake_internal(
+        struct Render *re, struct Object *object, const BakePixel pixel_array[],
+        const int num_pixels, const int depth, const ScenePassType pass_type, float result[]);
+
+void RE_bake_pixels_populate_from_objects(
+        struct Mesh *me_low, BakePixel pixel_array_from[],
+        BakeHighPolyData highpoly[], const int tot_highpoly, const int num_pixels,
+        const float cage_extrusion);
+
+void RE_bake_pixels_populate(
+        struct Mesh *me, struct BakePixel *pixel_array,
+        const int num_pixels, const struct BakeImages *bake_images);
+
+void RE_bake_mask_fill(const BakePixel pixel_array[], const int num_pixels, char *mask);
+
+void RE_bake_margin(struct ImBuf *ibuf, char *mask, const int margin);
+
+void RE_bake_normal_world_to_object(
+        const BakePixel pixel_array[], const int num_pixels, const int depth, float result[],
+        struct Object *ob, const BakeNormalSwizzle normal_swizzle[3]);
+void RE_bake_normal_world_to_tangent(
+        const BakePixel pixel_array[], const int num_pixels, const int depth, float result[],
+        struct Mesh *me, const BakeNormalSwizzle normal_swizzle[3]);
+void RE_bake_normal_world_to_world(
+        const BakePixel pixel_array[], const int num_pixels, const int depth, float result[],
+        const BakeNormalSwizzle normal_swizzle[3]);
+
+void RE_bake_ibuf_clear(struct BakeImages *bake_images, const bool is_tangent);
+
+#endif  /* __RE_BAKE_H__ */
diff --git a/source/blender/render/extern/include/RE_engine.h b/source/blender/render/extern/include/RE_engine.h
index bd976e6c14a..2c6492b5c5a 100644
--- a/source/blender/render/extern/include/RE_engine.h
+++ b/source/blender/render/extern/include/RE_engine.h
@@ -35,6 +35,7 @@
 #include "DNA_listBase.h"
 #include "DNA_scene_types.h"
 #include "RNA_types.h"
+#include "RE_bake.h"
 
 struct bNode;
 struct bNodeTree;
@@ -47,6 +48,7 @@ struct RenderLayer;
 struct RenderResult;
 struct ReportList;
 struct Scene;
+struct BakePixel;
 
 /* External Engine */
 
@@ -85,6 +87,7 @@ typedef struct RenderEngineType {
 
 	void (*update)(struct RenderEngine *engine, struct Main *bmain, struct Scene *scene);
 	void (*render)(struct RenderEngine *engine, struct Scene *scene);
+	void (*bake)(struct RenderEngine *engine, struct Scene *scene, struct Object *object, const int pass_type, const struct BakePixel *pixel_array, const int num_pixels, const int depth, void *result);
 
 	void (*view_update)(struct RenderEngine *engine, const struct bContext *context);
 	void (*view_draw)(struct RenderEngine *engine, const struct bContext *context);
@@ -153,6 +156,7 @@ RenderEngineType *RE_engines_find(const char *idname);
 
 void RE_engine_get_current_tiles(struct Render *re, int *total_tiles_r, rcti **tiles_r);
 struct RenderData *RE_engine_get_render_data(struct Render *re);
+void RE_bake_engine_set_engine_parameters(struct Render *re, struct Main *bmain, struct Scene *scene);
 
 #endif /* __RE_ENGINE_H__ */