== Transform ==

Embryon functionnality for snapping.

- Only snaps to grid on translations (grab)
- Transform constraints are supported but header display is wrong.
- Can be turned on/off in the Object/Mesh header menu under Transform Properties (tentative spot, will have to integrate better and in other object type menus too)
- Can be turned on/off during transform with ` (Back Quote, also tentative)

This is, of course, very much Work in Progress.

This implements part of the structural ideas for the transform cleanup I've been juggling around with.

6 files changed, 291 insertions, 63 deletions

diff --git a/source/blender/include/transform.h b/source/blender/include/transform.h
index ec55b768381..d91fe81d991 100755
--- a/source/blender/include/transform.h
+++ b/source/blender/include/transform.h
@@ -59,6 +59,13 @@ typedef struct NumInput {
 		Negative	: number is negative
 */
 
+typedef struct TransSnap {
+	int  status;
+	float snapPoint[3];
+	void (*applySnap)(struct TransInfo *, float *);
+	void (*calcSnap)(struct TransInfo *, float *);
+} TransSnap;
+
 typedef struct TransCon {
     char  text[50];      /* Description of the Constraint for header_print                            */
     float mtx[3][3];     /* Matrix of the Constraint space                                            */
@@ -147,6 +154,7 @@ typedef struct TransInfo {
 	TransDataExtension *ext;	/* transformed data extension (array)   */
 	TransData2D *data2d;		/* transformed data for 2d (array)      */
     TransCon    con;            /* transformed constraint               */
+    TransSnap	tsnap;
     NumInput    num;            /* numerical input                      */
     char        redraw;         /* redraw flag                          */
 	float		propsize;		/* proportional circle radius           */
@@ -331,6 +339,23 @@ void postSelectConstraint(TransInfo *t);
 
 void setNearestAxis(TransInfo *t);
 
+/*********************** Snapping ********************************/
+
+typedef enum {
+	NO_GEARS 	= 0,
+	BIG_GEARS	= 1,
+	SMALL_GEARS	= 2
+} GearsType;
+
+void snapGrid(TransInfo *t, float *val);
+void snapGridAction(TransInfo *t, float *val, GearsType action);
+
+void initSnapping(struct TransInfo *t);
+void applySnapping(TransInfo *t, float *vec);
+void resetSnapping(TransInfo *t);
+int  handleSnapping(TransInfo *t, int event);
+void drawSnapping(TransInfo *t);
+
 /*********************** Generics ********************************/
 
 void initTrans(TransInfo *t);
@@ -356,8 +381,6 @@ void calculateCenterCursor(TransInfo *t);
 
 void calculatePropRatio(TransInfo *t);
 
-void snapGrid(TransInfo *t, float *val);
-
 void getViewVector(float coord[3], float vec[3]);
 
 TransInfo * BIF_GetTransInfo(void);
diff --git a/source/blender/makesdna/DNA_view3d_types.h b/source/blender/makesdna/DNA_view3d_types.h
index b62c815b2b2..dda40b67bf7 100644
--- a/source/blender/makesdna/DNA_view3d_types.h
+++ b/source/blender/makesdna/DNA_view3d_types.h
@@ -158,6 +158,7 @@ typedef struct View3D {
 /* View3d->flag2 (short) */
 #define V3D_OPP_DIRECTION_NAME	1
 #define V3D_FLYMODE				2
+#define V3D_TRANSFORM_SNAP		4
 
 /* View3D->around */
 #define V3D_CENTRE		 0
diff --git a/source/blender/src/header_view3d.c b/source/blender/src/header_view3d.c
index 93b9832b5b8..478f96d331c 100644
--- a/source/blender/src/header_view3d.c
+++ b/source/blender/src/header_view3d.c
@@ -2152,6 +2152,9 @@ static void do_view3d_edit_objectmenu(void *arg, int event)
 		if(session) b_verse_push_object(session, ob);
 		break;
 #endif
+	case 17: /* Transform snap to grid */
+		G.vd->flag2 ^= V3D_TRANSFORM_SNAP;
+		break;
 	}
 	allqueue(REDRAWVIEW3D, 0);
 }
@@ -2177,6 +2180,12 @@ static uiBlock *view3d_edit_objectmenu(void *arg_unused)
 	}
 #endif
 
+	if (G.vd->flag2 & V3D_TRANSFORM_SNAP)
+		uiDefIconTextBut(block, BUTM, 1, ICON_CHECKBOX_HLT, "Transform Snap",			0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 1, 17, "");
+	else
+		uiDefIconTextBut(block, BUTM, 1, ICON_CHECKBOX_DEHLT, "Transform Snap",			0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 1, 17, "");
+	
+
 	uiDefIconTextBut(block, BUTM, 1, ICON_MENU_PANEL, "Transform Properties|N",		0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 0, 15, "");
 	uiDefIconTextBlockBut(block, view3d_transformmenu, NULL, ICON_RIGHTARROW_THIN, "Transform", 0, yco-=20, 120, 19, "");
 	uiDefIconTextBlockBut(block, view3d_object_mirrormenu, NULL, ICON_RIGHTARROW_THIN, "Mirror", 0, yco-=20, menuwidth, 19, "");
@@ -2712,6 +2721,9 @@ static void do_view3d_edit_meshmenu(void *arg, int event)
 		if(session) b_verse_push_object(session, G.obedit);
 		break;
 #endif
+	case 17: /* Transform snap to grid */
+		G.vd->flag2 ^= V3D_TRANSFORM_SNAP;
+		break;
 	}
 	allqueue(REDRAWVIEW3D, 0);
 }
@@ -2739,6 +2751,11 @@ static uiBlock *view3d_edit_meshmenu(void *arg_unused)
 	
 	uiDefBut(block, SEPR, 0, "",				0, yco-=6, menuwidth, 6, NULL, 0.0, 0.0, 0, 0, "");
 	
+	if (G.vd->flag2 & V3D_TRANSFORM_SNAP)
+		uiDefIconTextBut(block, BUTM, 1, ICON_CHECKBOX_HLT, "Transform Snap",			0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 1, 17, "");
+	else
+		uiDefIconTextBut(block, BUTM, 1, ICON_CHECKBOX_DEHLT, "Transform Snap",			0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 1, 17, "");
+
 	uiDefIconTextBut(block, BUTM, 1, ICON_MENU_PANEL, "Transform Properties...|N",		0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 1, 2, "");
 	uiDefIconTextBlockBut(block, view3d_transformmenu, NULL, ICON_RIGHTARROW_THIN, "Transform", 0, yco-=20, 120, 19, "");
 	uiDefIconTextBlockBut(block, view3d_edit_mirrormenu, NULL, ICON_RIGHTARROW_THIN, "Mirror", 0, yco-=20, 120, 19, "");
diff --git a/source/blender/src/transform.c b/source/blender/src/transform.c
index 1e5f481ac8b..14a41b0a5dc 100755
--- a/source/blender/src/transform.c
+++ b/source/blender/src/transform.c
@@ -699,6 +699,7 @@ static void transformEvent(unsigned short event, short val) {
 			break;
 		}
 		Trans.redraw |= handleNumInput(&(Trans.num), event);
+		Trans.redraw |= handleSnapping(&Trans, event);
 		arrows_move_cursor(event);
 	}
 	else {
@@ -2053,6 +2054,8 @@ void initTranslation(TransInfo *t)
 		t->snap[0] = 0.0f;
 		t->snap[1] = t->snap[2] = 1.0f;
 	}
+	
+	initSnapping(t);
 }
 
 static void headerTranslation(TransInfo *t, float vec[3], char *str) {
@@ -2152,14 +2155,16 @@ int Translation(TransInfo *t, short mval[2])
 		float pvec[3] = {0.0f, 0.0f, 0.0f};
 		t->con.applyVec(t, NULL, t->vec, tvec, pvec);
 		VECCOPY(t->vec, tvec);
+		applySnapping(t, t->vec);
 		headerTranslation(t, pvec, str);
 	}
 	else {
 		snapGrid(t, t->vec);
 		applyNumInput(&t->num, t->vec);
+		applySnapping(t, t->vec);
 		headerTranslation(t, t->vec, str);
 	}
-
+	
 	applyTranslation(t, t->vec);
 
 	/* evil hack - redo translation if cliiping needeed */
@@ -2169,9 +2174,11 @@ int Translation(TransInfo *t, short mval[2])
 	recalcData(t);
 
 	headerprint(str);
-
+	
 	viewRedrawForce(t);
 
+	drawSnapping(t);
+
 	return 1;
 }
 
diff --git a/source/blender/src/transform_generics.c b/source/blender/src/transform_generics.c
index 09ad6e7a788..0ed75810b42 100755
--- a/source/blender/src/transform_generics.c
+++ b/source/blender/src/transform_generics.c
@@ -480,6 +480,7 @@ void initTrans (TransInfo *t)
 		t->around = V3D_CENTRE;
 
 	setTransformViewMatrices(t);
+	resetSnapping(t);
 }
 
 /* Here I would suggest only TransInfo related issues, like free data & reset vars. Not redraws */
@@ -532,65 +533,6 @@ void postTrans (TransInfo *t)
 	}
 }
 
-static void apply_grid3(TransInfo *t, float *val, int max_index, float fac1, float fac2, float fac3)
-{
-	/* fac1 is for 'nothing', fac2 for CTRL, fac3 for SHIFT */
-	int invert;
-	int ctrl;
-	int i;
-	float asp= 1.0f;
-
-	if(t->mode==TFM_ROTATION || t->mode==TFM_WARP || t->mode==TFM_TILT || t->mode==TFM_TRACKBALL)
-		invert = U.flag & USER_AUTOROTGRID;
-	else if(t->mode==TFM_RESIZE || t->mode==TFM_SHEAR || t->mode==TFM_BONESIZE || t->mode==TFM_SHRINKFATTEN || t->mode==TFM_CURVE_SHRINKFATTEN)
-		invert = U.flag & USER_AUTOSIZEGRID;
-	else
-		invert = U.flag & USER_AUTOGRABGRID;
-	
-	for (i=0; i<=max_index; i++) {
-
-		/* evil hack - snapping needs to be adapted for image aspect ratio */
-		if((t->spacetype==SPACE_IMAGE) && (t->mode==TFM_TRANSLATION)) {
-			float aspx, aspy;
-			transform_aspect_ratio_tface_uv(&aspx, &aspy);
-			if(i==0) asp= aspx;
-			else asp= aspy;
-		}
-
-		if(invert) {
-			if(G.qual & LR_CTRLKEY) ctrl= 0;
-			else ctrl= 1;
-		}
-		else ctrl= (G.qual & LR_CTRLKEY);
-
-		if(ctrl && (G.qual & LR_SHIFTKEY)) {
-			if(fac3!= 0.0) {
-				for (i=0; i<=max_index; i++) {
-					val[i]= fac3*asp*(float)floor(val[i]/(fac3*asp) +.5);
-				}
-			}
-		}
-		else if(ctrl) {
-			if(fac2!= 0.0) {
-				for (i=0; i<=max_index; i++) {
-					val[i]= fac2*asp*(float)floor(val[i]/(fac2*asp) +.5);
-				}
-			}
-		}
-		else {
-			if(fac1!= 0.0) {
-				for (i=0; i<=max_index; i++) {
-					val[i]= fac1*asp*(float)floor(val[i]/(fac1*asp) +.5);
-				}
-			}
-		}
-	}
-}
-
-void snapGrid(TransInfo *t, float *val) {
-	apply_grid3(t, val, t->idx_max, t->snap[0], t->snap[1], t->snap[2]);
-}
-
 void applyTransObjects(TransInfo *t)
 {
 	TransData *td;
diff --git a/source/blender/src/transform_snap.c b/source/blender/src/transform_snap.c
new file mode 100644
index 00000000000..53d1822ae70
--- /dev/null
+++ b/source/blender/src/transform_snap.c
@@ -0,0 +1,238 @@
+/**
+ * $Id: 
+ *
+ * ***** BEGIN GPL/BL DUAL 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. The Blender
+ * Foundation also sells licenses for use in proprietary software under
+ * the Blender License.  See http://www.blender.org/BL/ for information
+ * about this.
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): Martin Poirier
+ *
+ * ***** END GPL/BL DUAL LICENSE BLOCK *****
+ */
+ 
+#include <stdlib.h>
+#include <math.h>
+
+#include "DNA_object_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_userdef_types.h"
+#include "DNA_view3d_types.h"
+
+#include "BLI_arithb.h"
+
+#include "BDR_drawobject.h"
+
+#include "BIF_editsima.h"
+#include "BIF_gl.h"
+#include "BIF_glutil.h"
+#include "BIF_mywindow.h"
+#include "BIF_resources.h"
+
+#include "BKE_global.h"
+#include "BKE_utildefines.h"
+
+#include "transform.h"
+#include "mydevice.h"		/* for KEY defines	*/
+
+#define SNAP_ON	1
+
+/********************* PROTOTYPES ***********************/
+
+void setSnappingCallback(TransInfo *t);
+void SnapTranslation(TransInfo *t, float vec[3]);
+void SnapRotation(TransInfo *t, float *vec);
+
+void CalcSnapGrid(TransInfo *t, float vec[3]);
+
+
+/****************** IMPLEMENTATIONS *********************/
+
+void drawSnapping(TransInfo *t)
+{
+	if (t->tsnap.status & SNAP_ON) {
+		// Do something nice
+	}
+}
+
+int  handleSnapping(TransInfo *t, int event)
+{
+	int status = 0;
+	
+	switch(event) {
+	case ACCENTGRAVEKEY:
+		t->tsnap.status ^= SNAP_ON;
+		status = 1;
+		break;
+	}
+	
+	return status;
+}
+
+void applySnapping(TransInfo *t, float *vec)
+{
+	if ((t->tsnap.status & SNAP_ON) && t->tsnap.applySnap != NULL)
+	{
+		t->tsnap.applySnap(t, vec);
+	}
+}
+
+void resetSnapping(TransInfo *t)
+{
+	t->tsnap.status = 0;
+	t->tsnap.applySnap = NULL;
+}
+
+void initSnapping(TransInfo *t)
+{
+	setSnappingCallback(t);
+	
+	if (G.vd->flag2 & V3D_TRANSFORM_SNAP)
+	{
+		t->tsnap.status |= SNAP_ON;
+	}
+	else
+	{
+		t->tsnap.status &= ~SNAP_ON;
+	}
+}
+
+void setSnappingCallback(TransInfo *t)
+{
+	switch (t->mode)
+	{
+	case TFM_TRANSLATION:
+		t->tsnap.applySnap = SnapTranslation;
+		t->tsnap.calcSnap = CalcSnapGrid;
+		break;
+	case TFM_ROTATION:
+		t->tsnap.applySnap = NULL; //SnapRotation;
+		//t->tsnap.calcSnap = CalcSnapGrid;
+		break;
+	case TFM_RESIZE:
+		t->tsnap.applySnap = NULL;
+		break;
+	default:
+		t->tsnap.applySnap = NULL;
+		break;
+	}
+}
+
+void SnapTranslation(TransInfo *t, float vec[3])
+{
+	float center[3];
+
+	VECCOPY(center, t->center);	
+	if(t->flag & (T_EDIT|T_POSE)) {
+		Object *ob= G.obedit?G.obedit:t->poseobj;
+		Mat4MulVecfl(ob->obmat, center);
+	}
+	
+	VecAddf(t->tsnap.snapPoint, vec, center);
+
+	t->tsnap.calcSnap(t, t->tsnap.snapPoint);
+	
+	VecSubf(vec, t->tsnap.snapPoint, center);
+	
+	if (t->con.mode & CON_APPLY)
+	{
+		Mat3MulVecfl(t->con.pmtx, vec);
+	}
+}
+
+void SnapRotation(TransInfo *t, float *vec)
+{
+	TransData *td;
+	
+	td = t->data;
+	
+	VECCOPY(t->tsnap.snapPoint, td->loc);
+	t->tsnap.calcSnap(t, t->tsnap.snapPoint);
+	
+	
+}
+
+void CalcSnapGrid(TransInfo *t, float vec[3])
+{
+	snapGridAction(t, vec, BIG_GEARS);
+}
+
+/*================================================================*/
+
+static void applyGrid(TransInfo *t, float *val, int max_index, float fac[3], GearsType action);
+
+
+void snapGridAction(TransInfo *t, float *val, GearsType action) {
+	float fac[3];
+
+	fac[NO_GEARS]    = t->snap[0];
+	fac[BIG_GEARS]   = t->snap[1];
+	fac[SMALL_GEARS] = t->snap[2];
+	
+	applyGrid(t, val, t->idx_max, fac, action);
+}
+
+
+void snapGrid(TransInfo *t, float *val) {
+	int invert;
+	GearsType action;
+
+	if(t->mode==TFM_ROTATION || t->mode==TFM_WARP || t->mode==TFM_TILT || t->mode==TFM_TRACKBALL)
+		invert = U.flag & USER_AUTOROTGRID;
+	else if(t->mode==TFM_RESIZE || t->mode==TFM_SHEAR || t->mode==TFM_BONESIZE || t->mode==TFM_SHRINKFATTEN || t->mode==TFM_CURVE_SHRINKFATTEN)
+		invert = U.flag & USER_AUTOSIZEGRID;
+	else
+		invert = U.flag & USER_AUTOGRABGRID;
+
+	if(invert) {
+		action = (G.qual & LR_CTRLKEY) ? NO_GEARS: BIG_GEARS;
+	}
+	else {
+		action = (G.qual & LR_CTRLKEY) ? BIG_GEARS : NO_GEARS;
+	}
+	
+	if (action == BIG_GEARS && (G.qual & LR_SHIFTKEY)) {
+		action = SMALL_GEARS;
+	}
+
+	snapGridAction(t, val, action);
+}
+
+
+static void applyGrid(TransInfo *t, float *val, int max_index, float fac[3], GearsType action)
+{
+	int i;
+	float asp[3] = {1.0f, 1.0f, 1.0f}; // TODO: Remove hard coded limit here (3)
+
+	// Early bailing out if no need to snap
+	if (fac[action] == 0.0)
+		return;
+	
+	/* evil hack - snapping needs to be adapted for image aspect ratio */
+	if((t->spacetype==SPACE_IMAGE) && (t->mode==TFM_TRANSLATION)) {
+		transform_aspect_ratio_tface_uv(asp, asp+1);
+	}
+
+	for (i=0; i<=max_index; i++) {
+		val[i]= fac[action]*asp[i]*(float)floor(val[i]/(fac[action]*asp[i]) +.5);
+	}
+}