Option to correct for UV distortion when edge sliding when the surrounding faces share the same UV location (else uv interpolation is ignored for that vert).

Enable this from the UV Calculation panel, "Transform Correction" button.
This also means deleting edge loops keeps uvs where possible (even when Transform Correction isnt enabled).
Works for multiple UV layers.

1 files changed, 176 insertions, 1 deletions

diff --git a/source/blender/src/editmesh_tools.c b/source/blender/src/editmesh_tools.c
index f9bb14a08c6..0384caf0e59 100644
--- a/source/blender/src/editmesh_tools.c
+++ b/source/blender/src/editmesh_tools.c
@@ -4646,6 +4646,11 @@ void bevel_menu_old()
 }
 
 /* *********** END BEVEL *********/
+typedef struct SlideUv {
+	float origuv[2];
+	float *uv_up, *uv_down;
+	float *fuv[4];
+} SlideUv;
 
 typedef struct SlideVert {
 	EditEdge *up,*down;
@@ -4653,9 +4658,19 @@ typedef struct SlideVert {
 } SlideVert;
 
 int EdgeLoopDelete(void) {
+	
+	/* temporal flag setting so we keep UVs when deleting edge loops,
+	 * this is a bit of a hack but it works how you would want in almost all cases */
+	short uvcalc_flag_orig = G.scene->toolsettings->uvcalc_flag; 
+	G.scene->toolsettings->uvcalc_flag |= UVCALC_NO_TRANSFORM_CORRECT;
+	
 	if(!EdgeSlide(1, 1)) {
 		return 0;
 	}
+	
+	/* restore uvcalc flag */
+	G.scene->toolsettings->uvcalc_flag = uvcalc_flag_orig;
+	
 	EM_select_more();
 	removedoublesflag(1,0, 0.001);
 	EM_select_flush();
@@ -4671,11 +4686,19 @@ int EdgeSlide(short immediate, float imperc)
 	EditVert *ev, *nearest;
 	LinkNode *edgelist = NULL, *vertlist=NULL, *look;
 	GHash *vertgh;
+
 	SlideVert *tempsv;
 	float perc = 0, percp = 0,vertdist, projectMat[4][4], viewMat[4][4];
 	float shiftlabda= 0.0f,len = 0.0f;
 	int i = 0,j, numsel, numadded=0, timesthrough = 0, vertsel=0, prop=1, cancel = 0,flip=0;
 	int wasshift = 0;
+	
+	/* UV correction vars */
+	GHash **uvarray;
+	int  uvlay_tot= CustomData_number_of_layers(&G.editMesh->fdata, CD_MTFACE);
+	int uvlay_idx;
+	SlideUv *slideuvs, *suv, *suv_last;	
+	
 	short event, draw=1;
 	short mval[2], mvalo[2];
 	char str[128]; 
@@ -4980,6 +5003,111 @@ int EdgeSlide(short immediate, float imperc)
 		
 		look = look->next;   
 	}	   
+	
+	
+	if (uvlay_tot && (G.scene->toolsettings->uvcalc_flag & UVCALC_NO_TRANSFORM_CORRECT)) {
+		int maxnum = 0;
+		uvarray = MEM_callocN( uvlay_tot * sizeof(GHash *), "SlideUVs Array");
+		suv_last = slideuvs = MEM_callocN( uvlay_tot * (numadded+1) * sizeof(SlideUv), "SlideUVs"); /* uvLayers * verts */
+		suv = NULL;
+		
+		for (uvlay_idx=0; uvlay_idx<uvlay_tot; uvlay_idx++) {
+			
+			uvarray[uvlay_idx] = BLI_ghash_new(BLI_ghashutil_ptrhash, BLI_ghashutil_ptrcmp); 
+			
+			for(ev=em->verts.first;ev;ev=ev->next) {
+				ev->tmp.l = 0;
+			}
+			look = vertlist;
+			while(look) {
+				float *uv_new;
+				tempsv  = BLI_ghash_lookup(vertgh,(EditVert*)look->link);
+				
+				ev = look->link;
+				suv = NULL;
+				for(efa = em->faces.first;efa;efa=efa->next) {
+					if (ev->tmp.l != -1) { /* test for self, in this case its invalid */
+						int k=-1; /* face corner */
+					
+						/* Is this vert in the faces corner? */
+						if		(efa->v1==ev)				k=0;
+						else if	(efa->v2==ev)				k=1;
+						else if	(efa->v3==ev)				k=2;
+						else if	(efa->v4 && efa->v4==ev)	k=3;
+						
+						if (k != -1) {
+							MTFace *tf = CustomData_em_get_n(&em->fdata, efa->data, CD_MTFACE, uvlay_idx);
+							uv_new = tf->uv[k];
+						
+							EditVert *ev_up, *ev_down;
+				
+							if (ev->tmp.l) {
+								if (fabs(suv->fuv[0][0]-uv_new[0]) > 0.0001 || fabs(suv->fuv[0][1]-uv_new[1])) {
+									ev->tmp.l = -1; /* Tag as invalid */
+									suv->fuv[0] = suv->fuv[1] = suv->fuv[2] = suv->fuv[3] = NULL;
+									BLI_ghash_remove(uvarray[uvlay_idx],ev, NULL, NULL);
+									suv = NULL;
+									break;
+								}
+							} else {
+								ev->tmp.l = 1;
+								suv = suv_last;
+
+								suv->fuv[0] = suv->fuv[1] = suv->fuv[2] = suv->fuv[3] = NULL;
+								suv->uv_up = suv->uv_down = NULL;
+								
+								BLI_ghash_insert(uvarray[uvlay_idx],ev,suv);
+								
+								suv_last++; /* advance to next slide UV */
+								maxnum++;
+							}
+				
+							/* Now get the uvs along the up or down edge if we can */
+							if (suv) {
+								if (!suv->uv_up) {
+									ev_up = editedge_getOtherVert(tempsv->up,ev);
+									if		(efa->v1==ev_up)				suv->uv_up = tf->uv[0];
+									else if	(efa->v2==ev_up)				suv->uv_up = tf->uv[1];
+									else if	(efa->v3==ev_up)				suv->uv_up = tf->uv[2];
+									else if	(efa->v4 && efa->v4==ev_up)		suv->uv_up = tf->uv[3];
+								}
+								if (!suv->uv_down) { /* if the first face was apart of the up edge, it cant be apart of the down edge */
+									ev_down = editedge_getOtherVert(tempsv->down,ev);
+									if		(efa->v1==ev_down)				suv->uv_down = tf->uv[0];
+									else if	(efa->v2==ev_down)				suv->uv_down = tf->uv[1];
+									else if	(efa->v3==ev_down)				suv->uv_down = tf->uv[2];
+									else if	(efa->v4 && efa->v4==ev_down)	suv->uv_down = tf->uv[3];
+								}
+					
+								/* Copy the pointers to the face UV's */
+								for (k=0; k<4; k++) {
+									if (!suv->fuv[k]) {
+										suv->fuv[k] = uv_new;
+										break;
+									}
+								}
+					
+								if (k==3) { /* Dont look any further since 4 faces gace been found */
+								 	break;
+								}
+							}
+					
+						}
+					}
+				}
+		
+				/* UV SUPPORT */
+				if (suv && suv->fuv[0]) {
+					suv->origuv[0] = suv->fuv[0][0];
+					suv->origuv[1] = suv->fuv[0][1];
+				}
+				look = look->next;
+			}
+		} /* end uv layer loop */
+	} /* end uvlay_tot */
+	
+	
+	
 	// we should have enough info now to slide
 
 	len = 0.0f; 
@@ -5017,7 +5145,19 @@ int EdgeSlide(short immediate, float imperc)
 					
 					tempev = editedge_getOtherVert((perc>=0)?tempsv->up:tempsv->down, ev);
 					VecLerpf(ev->co, tempsv->origvert.co, tempev->co, fabs(perc));
-									
+					
+					if (G.scene->toolsettings->uvcalc_flag & UVCALC_NO_TRANSFORM_CORRECT) {
+						for (uvlay_idx=0; uvlay_idx<uvlay_tot; uvlay_idx++) {
+							suv = BLI_ghash_lookup( uvarray[uvlay_idx], ev );
+							if (suv && suv->fuv[0] && suv->uv_up && suv->uv_down) {
+								VecLerpf2D(suv->fuv[0], suv->origuv,  (perc>=0)?suv->uv_up:suv->uv_down, fabs(perc));
+								if (suv->fuv[1]) VECCOPY2D(suv->fuv[1], suv->fuv[0]);
+								if (suv->fuv[2]) VECCOPY2D(suv->fuv[2], suv->fuv[0]);
+								if (suv->fuv[3]) VECCOPY2D(suv->fuv[3], suv->fuv[0]);
+							}
+						}
+					}
+					
 					look = look->next;	 
 				}
 			}
@@ -5033,8 +5173,33 @@ int EdgeSlide(short immediate, float imperc)
 					if(newlen < 0.0) {newlen = 0.0;}
 					if(flip == 0) {
 						VecLerpf(ev->co, editedge_getOtherVert(tempsv->down,ev)->co, editedge_getOtherVert(tempsv->up,ev)->co, fabs(newlen));									
+						if (G.scene->toolsettings->uvcalc_flag & UVCALC_NO_TRANSFORM_CORRECT) {
+							/* dont do anything if no UVs */
+							for (uvlay_idx=0; uvlay_idx<uvlay_tot; uvlay_idx++) {
+								suv = BLI_ghash_lookup( uvarray[uvlay_idx], ev );
+								if (suv && suv->fuv[0] && suv->uv_up && suv->uv_down) {
+									VecLerpf2D(suv->fuv[0], suv->uv_down, suv->uv_up, fabs(newlen));
+									if (suv->fuv[1]) VECCOPY2D(suv->fuv[1], suv->fuv[0]);
+									if (suv->fuv[2]) VECCOPY2D(suv->fuv[2], suv->fuv[0]);
+									if (suv->fuv[3]) VECCOPY2D(suv->fuv[3], suv->fuv[0]);
+								}
+							}
+						}
 					} else{
 						VecLerpf(ev->co, editedge_getOtherVert(tempsv->up,ev)->co, editedge_getOtherVert(tempsv->down,ev)->co, fabs(newlen));				
+						
+						if (G.scene->toolsettings->uvcalc_flag & UVCALC_NO_TRANSFORM_CORRECT) {
+							/* dont do anything if no UVs */
+							for (uvlay_idx=0; uvlay_idx<uvlay_tot; uvlay_idx++) {
+								suv = BLI_ghash_lookup( uvarray[uvlay_idx], ev );
+								if (suv && suv->fuv[0] && suv->uv_up && suv->uv_down) {
+									VecLerpf2D(suv->fuv[0], suv->uv_up, suv->uv_down, fabs(newlen));
+									if (suv->fuv[1]) VECCOPY2D(suv->fuv[1], suv->fuv[0]);
+									if (suv->fuv[2]) VECCOPY2D(suv->fuv[2], suv->fuv[0]);
+									if (suv->fuv[3]) VECCOPY2D(suv->fuv[3], suv->fuv[0]);
+								}
+							}
+						}
 					}
 					look = look->next;	 
 				}
@@ -5216,6 +5381,16 @@ int EdgeSlide(short immediate, float imperc)
 	BLI_ghash_free(vertgh, NULL, (GHashValFreeFP)MEM_freeN);
 	BLI_linklist_free(vertlist,NULL); 
 	BLI_linklist_free(edgelist,NULL); 
+	
+	if (uvlay_tot && (G.scene->toolsettings->uvcalc_flag & UVCALC_NO_TRANSFORM_CORRECT)) {
+		for (uvlay_idx=0; uvlay_idx<uvlay_tot; uvlay_idx++) {
+			BLI_ghash_free(uvarray[uvlay_idx], NULL, NULL);
+		}
+		MEM_freeN(uvarray);
+		MEM_freeN(slideuvs);
+		
+		allqueue(REDRAWIMAGE, 0);
+	}
 
 	if(cancel == 1) {
 		return -1;