Move curve's boundbox and texspace calculation out of modifier stack

There were several issues with how bounding box and texture space
are calculated:

- This was done at the same time as applying modifiers, meaning if
  several objects are sharing the same curve datablock, bounding
  box and texture space will be calculated multiple times.

  Further, allocating bounding box wasn't safe for threading.

- Bounding box and texture space were evaluated after pre-tessellation
  modifiers are applied. This means Curve-level data is actually
  depends on object data, and it's really bad because different
  objects could have different modifiers and this leads to
  conflicts (curve's data depends on object evaluation order)
  and doesn't behave in a predictable way.

  This commit moves bounding box and texture space evaluation from
  modifier stack to own utility functions, just like it's was done
  for meshes.

  This makes curve objects update thread-safe, but gives some
  limitations as well. Namely, with such approach it's not so
  clear how to preserve the same behavior of texture space:
  before this change texture space and bounding box would match
  beveled curve as accurate as possible.

  Old behavior was nice for quick texturing -- in most cases you
  didn't need to modify texture space at all. But texture space
  was depending on render/preview settings which could easily lead
  to situations, when final result would be far different from
  preview one.

  Now we're using CV points coordinates and their radius to approximate
  the bounding box. This doesn't give the same exact texture space,
  but it helps a lot keeping texture space in a nice predictable way.

  We could make approximation smarter in the future, but fir now
  added operator to match texture space to fully tessellated curve
  called "Match Texture Space".

Review link:

  https://codereview.appspot.com/15410043/

Brief description:

  http://wiki.blender.org/index.php/User:Nazg-gul/GSoC-2013/Results#Curve_Texture_Space

1 files changed, 63 insertions, 0 deletions

diff --git a/source/blender/editors/curve/editcurve.c b/source/blender/editors/curve/editcurve.c
index def0d3cba50..caa06eb15d0 100644
--- a/source/blender/editors/curve/editcurve.c
+++ b/source/blender/editors/curve/editcurve.c
@@ -47,6 +47,7 @@
 #include "BKE_context.h"
 #include "BKE_curve.h"
 #include "BKE_depsgraph.h"
+#include "BKE_displist.h"
 #include "BKE_fcurve.h"
 #include "BKE_global.h"
 #include "BKE_key.h"
@@ -6807,3 +6808,65 @@ int ED_curve_actSelection(Curve *cu, float center[3])
 
 	return 1;
 }
+
+/******************** Match texture space operator ***********************/
+
+static int match_texture_space_poll(bContext *C)
+{
+	Object *object = CTX_data_active_object(C);
+
+	return object && ELEM3(object->type, OB_CURVE, OB_SURF, OB_FONT);
+}
+
+static int match_texture_space_exec(bContext *C, wmOperator *UNUSED(op))
+{
+	Scene *scene = CTX_data_scene(C);
+	Object *object = CTX_data_active_object(C);
+	Curve *curve = (Curve *) object->data;
+	float min[3], max[3], size[3], loc[3];
+	int a;
+
+	if (ELEM(NULL, object->curve_cache, object->curve_cache->disp.first)) {
+		BKE_displist_make_curveTypes(scene, object, FALSE);
+	}
+
+	INIT_MINMAX(min, max);
+	BKE_displist_minmax(&object->curve_cache->disp, min, max);
+
+	mid_v3_v3v3(loc, min, max);
+
+	size[0] = (max[0] - min[0]) / 2.0f;
+	size[1] = (max[1] - min[1]) / 2.0f;
+	size[2] = (max[2] - min[2]) / 2.0f;
+
+	for (a = 0; a < 3; a++) {
+		if (size[a] == 0.0f) size[a] = 1.0f;
+		else if (size[a] > 0.0f && size[a] < 0.00001f) size[a] = 0.00001f;
+		else if (size[a] < 0.0f && size[a] > -0.00001f) size[a] = -0.00001f;
+	}
+
+	copy_v3_v3(curve->loc, loc);
+	copy_v3_v3(curve->size, size);
+	zero_v3(curve->rot);
+
+	curve->texflag &= ~CU_AUTOSPACE;
+
+	WM_event_add_notifier(C, NC_GEOM | ND_DATA, curve);
+
+	return OPERATOR_FINISHED;
+}
+
+void CURVE_OT_match_texture_space(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Match Texture Space";
+	ot->idname = "CURVE_OT_match_texture_space";
+	ot->description = "Match texture space to object's bounding box";
+
+	/* api callbacks */
+	ot->exec = match_texture_space_exec;
+	ot->poll = match_texture_space_poll;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}