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

1 files changed, 219 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index f2ff350178f..7b415cff555 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -53,6 +53,8 @@
 #include "BKE_modifier.h"
 #include "BKE_multires.h"
 #include "BKE_key.h"
+#include "BKE_mball.h"
+#include "BKE_depsgraph.h"
 /* these 2 are only used by conversion functions */
 #include "BKE_curve.h"
 /* -- */
@@ -2085,3 +2087,220 @@ void BKE_mesh_mselect_active_set(Mesh *me, int index, int type)
 	BLI_assert((me->mselect[me->totselect - 1].index == index) &&
 	           (me->mselect[me->totselect - 1].type  == type));
 }
+
+/* settings: 1 - preview, 2 - render */
+Mesh *BKE_mesh_new_from_object(
+        Main *bmain, Scene *sce, Object *ob,
+        int apply_modifiers, int settings, int calc_tessface, int calc_undeformed)
+{
+	Mesh *tmpmesh;
+	Curve *tmpcu = NULL, *copycu;
+	Object *tmpobj = NULL;
+	int render = settings == eModifierMode_Render, i;
+	int cage = !apply_modifiers;
+
+	/* perform the mesh extraction based on type */
+	switch (ob->type) {
+		case OB_FONT:
+		case OB_CURVE:
+		case OB_SURF:
+		{
+			ListBase dispbase = {NULL, NULL};
+			DerivedMesh *derivedFinal = NULL;
+			int uv_from_orco;
+
+			/* copies object and modifiers (but not the data) */
+			tmpobj = BKE_object_copy_ex(bmain, ob, true);
+			tmpcu = (Curve *)tmpobj->data;
+			tmpcu->id.us--;
+
+			/* if getting the original caged mesh, delete object modifiers */
+			if (cage)
+				BKE_object_free_modifiers(tmpobj);
+
+			/* copies the data */
+			copycu = tmpobj->data = BKE_curve_copy((Curve *) ob->data);
+
+			/* temporarily set edit so we get updates from edit mode, but
+			 * also because for text datablocks copying it while in edit
+			 * mode gives invalid data structures */
+			copycu->editfont = tmpcu->editfont;
+			copycu->editnurb = tmpcu->editnurb;
+
+			/* get updated display list, and convert to a mesh */
+			BKE_displist_make_curveTypes_forRender(sce, tmpobj, &dispbase, &derivedFinal, false, render);
+
+			copycu->editfont = NULL;
+			copycu->editnurb = NULL;
+
+			tmpobj->derivedFinal = derivedFinal;
+
+			/* convert object type to mesh */
+			uv_from_orco = (tmpcu->flag & CU_UV_ORCO) != 0;
+			BKE_mesh_from_nurbs_displist(tmpobj, &dispbase, uv_from_orco);
+
+			tmpmesh = tmpobj->data;
+
+			BKE_displist_free(&dispbase);
+
+			/* BKE_mesh_from_nurbs changes the type to a mesh, check it worked.
+			 * if it didn't the curve did not have any segments or otherwise 
+			 * would have generated an empty mesh */
+			if (tmpobj->type != OB_MESH) {
+				BKE_libblock_free_us(G.main, tmpobj);
+				return NULL;
+			}
+
+			BKE_mesh_texspace_copy_from_object(tmpmesh, ob);
+
+			BKE_libblock_free_us(bmain, tmpobj);
+			break;
+		}
+
+		case OB_MBALL:
+		{
+			/* metaballs don't have modifiers, so just convert to mesh */
+			Object *basis_ob = BKE_mball_basis_find(sce, ob);
+			/* todo, re-generatre for render-res */
+			/* metaball_polygonize(scene, ob) */
+
+			if (ob != basis_ob)
+				return NULL;  /* only do basis metaball */
+
+			tmpmesh = BKE_mesh_add(bmain, "Mesh");
+			/* BKE_mesh_add gives us a user count we don't need */
+			tmpmesh->id.us--;
+
+			if (render) {
+				ListBase disp = {NULL, NULL};
+				/* TODO(sergey): This is gonna to work for until EvaluationContext
+				 *               only contains for_render flag. As soon as CoW is
+				 *               implemented, this is to be rethinked.
+				 */
+				EvaluationContext eval_ctx = {0};
+				eval_ctx.for_render = render;
+				BKE_displist_make_mball_forRender(&eval_ctx, sce, ob, &disp);
+				BKE_mesh_from_metaball(&disp, tmpmesh);
+				BKE_displist_free(&disp);
+			}
+			else {
+				ListBase disp = {NULL, NULL};
+				if (ob->curve_cache) {
+					disp = ob->curve_cache->disp;
+				}
+				BKE_mesh_from_metaball(&disp, tmpmesh);
+			}
+
+			BKE_mesh_texspace_copy_from_object(tmpmesh, ob);
+
+			break;
+
+		}
+		case OB_MESH:
+			/* copies object and modifiers (but not the data) */
+			if (cage) {
+				/* copies the data */
+				tmpmesh = BKE_mesh_copy_ex(bmain, ob->data);
+				/* if not getting the original caged mesh, get final derived mesh */
+			}
+			else {
+				/* Make a dummy mesh, saves copying */
+				DerivedMesh *dm;
+				/* CustomDataMask mask = CD_MASK_BAREMESH|CD_MASK_MTFACE|CD_MASK_MCOL; */
+				CustomDataMask mask = CD_MASK_MESH; /* this seems more suitable, exporter,
+			                                         * for example, needs CD_MASK_MDEFORMVERT */
+
+				if (calc_undeformed)
+					mask |= CD_MASK_ORCO;
+
+				/* Write the display mesh into the dummy mesh */
+				if (render)
+					dm = mesh_create_derived_render(sce, ob, mask);
+				else
+					dm = mesh_create_derived_view(sce, ob, mask);
+
+				tmpmesh = BKE_mesh_add(bmain, "Mesh");
+				DM_to_mesh(dm, tmpmesh, ob, mask);
+				dm->release(dm);
+			}
+
+			/* BKE_mesh_add/copy gives us a user count we don't need */
+			tmpmesh->id.us--;
+
+			break;
+		default:
+			/* "Object does not have geometry data") */
+			return NULL;
+	}
+
+	/* Copy materials to new mesh */
+	switch (ob->type) {
+		case OB_SURF:
+		case OB_FONT:
+		case OB_CURVE:
+			tmpmesh->totcol = tmpcu->totcol;
+
+			/* free old material list (if it exists) and adjust user counts */
+			if (tmpcu->mat) {
+				for (i = tmpcu->totcol; i-- > 0; ) {
+					/* are we an object material or data based? */
+
+					tmpmesh->mat[i] = ob->matbits[i] ? ob->mat[i] : tmpcu->mat[i];
+
+					if (tmpmesh->mat[i]) {
+						tmpmesh->mat[i]->id.us++;
+					}
+				}
+			}
+			break;
+
+#if 0
+		/* Crashes when assigning the new material, not sure why */
+		case OB_MBALL:
+			tmpmb = (MetaBall *)ob->data;
+			tmpmesh->totcol = tmpmb->totcol;
+
+			/* free old material list (if it exists) and adjust user counts */
+			if (tmpmb->mat) {
+				for (i = tmpmb->totcol; i-- > 0; ) {
+					tmpmesh->mat[i] = tmpmb->mat[i]; /* CRASH HERE ??? */
+					if (tmpmesh->mat[i]) {
+						tmpmb->mat[i]->id.us++;
+					}
+				}
+			}
+			break;
+#endif
+
+		case OB_MESH:
+			if (!cage) {
+				Mesh *origmesh = ob->data;
+				tmpmesh->flag = origmesh->flag;
+				tmpmesh->mat = MEM_dupallocN(origmesh->mat);
+				tmpmesh->totcol = origmesh->totcol;
+				tmpmesh->smoothresh = origmesh->smoothresh;
+				if (origmesh->mat) {
+					for (i = origmesh->totcol; i-- > 0; ) {
+						/* are we an object material or data based? */
+						tmpmesh->mat[i] = ob->matbits[i] ? ob->mat[i] : origmesh->mat[i];
+
+						if (tmpmesh->mat[i]) {
+							tmpmesh->mat[i]->id.us++;
+						}
+					}
+				}
+			}
+			break;
+	} /* end copy materials */
+
+	if (calc_tessface) {
+		/* cycles and exporters rely on this still */
+		BKE_mesh_tessface_ensure(tmpmesh);
+	}
+
+	/* make sure materials get updated in objects */
+	test_object_materials(bmain, &tmpmesh->id);
+
+	return tmpmesh;
+}
+