=Displace modifier fix=

This commit fixes displace modifier to propery support arbitrary uv
layers.  This seemed like a fairly big usability bug,
as displace modifiers would use the active UV layer (and thus could change when
you changed the active layer).  The modifier UI code now uses a menu for browsing
the uv layers, however only the uv layer name is actually stored, so that 
adding/deleting layers won't mess up displace modifiers.  

Whenever a displace modifier has an invalid UV name (for whatever reason) the 
UV name is set to the active layer.  This is checked both in the UI code and 
in the modifier exec code, so all bases are covered. For deleting a layer, this 
required upgrading the layer delete code in the UI to properly preserve the 
active layer, to prevent unwanted behaviour. I hope this is an ok solution.

Brecht, Ben you might want to look over and make sure I didn't break anything.  I don't
think I did, I tested as thouroughly as I could.

1 files changed, 89 insertions, 6 deletions

diff --git a/source/blender/src/buttons_editing.c b/source/blender/src/buttons_editing.c
index 3ec18a24ef0..b6b2176a9a4 100644
--- a/source/blender/src/buttons_editing.c
+++ b/source/blender/src/buttons_editing.c
@@ -690,15 +690,25 @@ static void delete_customdata_layer(void *data1, void *data2)
 	Mesh *me= (Mesh*)data1;
 	CustomData *data= (G.obedit)? &G.editMesh->fdata: &me->fdata;
 	CustomDataLayer *layer= (CustomDataLayer*)data2;
+	void *actlayerdata, *layerdata=layer->data;
 	int type= layer->type;
 	int index= CustomData_get_layer_index(data, type);
-
+	int i, actindex;
+	
+	/*ok, deleting a non-active layer needs to preserve the active layer indices.
+	  to do this, we store a pointer to the .data member of both layer and the active layer,
+	  (to detect if we're deleting the active layer or not), then use the active
+	  layer data pointer to find where the active layer has ended up.
+	  
+	  this is necassary because the deletion functions only support deleting the active
+	  layer. */
+	actlayerdata = data->layers[CustomData_get_active_layer_index(data, type)].data;
 	CustomData_set_layer_active(data, type, layer - &data->layers[index]);
 
 	/* Multires is handled seperately because the display data is separate
 	   from the data stored in multires */
 	if(me && me->mr) {
-		multires_delete_layer(me, &me->mr->fdata, CD_MTFACE, layer - &data->layers[index]);
+		multires_delete_layer(me, &me->mr->fdata, type, layer - &data->layers[index]);
 	}
 	else if(G.obedit) {
 		EM_free_data_layer(data, type);
@@ -715,8 +725,23 @@ static void delete_customdata_layer(void *data1, void *data2)
 			set_faceselect();  /* get out of faceselect mode */
 	}
 
+	/*reconstruct active layer*/
+	if (actlayerdata != layerdata) {
+		/*find index. . .*/
+		actindex = CustomData_get_layer_index(data, type);
+		for (i=actindex; i<data->totlayer; i++) {
+			if (data->layers[i].data == actlayerdata) {
+				actindex = i - actindex;
+				break;
+			}
+		}
+		
+		/*set index. . .*/
+		CustomData_set_layer_active(data, type, actindex);
+	}
+	
 	DAG_object_flush_update(G.scene, OBACT, OB_RECALC_DATA);
-
+	
 	if(type == CD_MTFACE)
 		BIF_undo_push("Delete UV Texture");
 	else if(type == CD_MCOL)
@@ -1355,6 +1380,21 @@ static void modifiers_convertToReal(void *ob_v, void *md_v)
 	BIF_undo_push("Modifier convert to real");
 }
 
+int stupid_uvmenu_var=0;
+
+void set_displace_uvlayer(void *arg1, void *arg2)
+{
+	DisplaceModifierData *dmd=arg1;
+	CustomDataLayer *layer = arg2;
+	int i;
+	
+	/*check we have UV layers*/
+	if (stupid_uvmenu_var < 1) return;
+	layer = layer + (stupid_uvmenu_var-1);
+	
+	strcpy(dmd->uvlayer_name, layer->name);
+}
+
 static void draw_modifier(uiBlock *block, Object *ob, ModifierData *md, int *xco, int *yco, int index, int cageIndex, int lastCageIndex)
 {
 	ModifierTypeInfo *mti = modifierType_getInfo(md->type);
@@ -1461,7 +1501,7 @@ static void draw_modifier(uiBlock *block, Object *ob, ModifierData *md, int *xco
 		} else if (md->type==eModifierType_Displace) {
 			DisplaceModifierData *dmd = (DisplaceModifierData *)md;
 			height = 124;
-			if(dmd->texmapping == MOD_DISP_MAP_OBJECT) height += 19;
+			if(dmd->texmapping == MOD_DISP_MAP_OBJECT || dmd->texmapping == MOD_DISP_MAP_UV) height += 19;
 		} else if (md->type==eModifierType_UVProject) {
 			height = 86 + ((UVProjectModifierData *)md)->num_projectors * 19;
 		} else if (md->type==eModifierType_Decimate) {
@@ -1483,8 +1523,8 @@ static void draw_modifier(uiBlock *block, Object *ob, ModifierData *md, int *xco
 			height = 48;
 		} else if (md->type==eModifierType_Array) {
 			height = 182;
-		}
-
+		} 
+		
 							/* roundbox 4 free variables: corner-rounding, nop, roundbox type, shade */
 		uiDefBut(block, ROUNDBOX, 0, "", x-10, y-height-2, width, height-2, NULL, 5.0, 0.0, 12, 40, ""); 
 
@@ -1603,6 +1643,49 @@ static void draw_modifier(uiBlock *block, Object *ob, ModifierData *md, int *xco
 			          lx, (cy -= 19), buttonWidth, 19, &dmd->texmapping,
 			          0.0, 1.0, 0, 0,
 			          "Texture coordinates used for displacement input");
+			if (dmd->texmapping == MOD_DISP_MAP_UV) {
+				char strtmp[1024], strtmp2[38];
+				int totuv, i;
+				CustomData *fdata = G.obedit?&G.editMesh->fdata:&((Mesh*)ob->data)->fdata;
+				CustomDataLayer *layer = &fdata->layers[CustomData_get_layer_index(fdata, CD_MTFACE)];
+				
+				stupid_uvmenu_var = -1;
+				
+				totuv=CustomData_number_of_layers(fdata, CD_MTFACE);
+				sprintf(strtmp, "UV Layer%%t");
+				for (i=0; i<totuv; i++) {
+					/*assign first layer as uvlayer_name if uvlayer_name is null.*/
+					if (strcmp(layer->name, dmd->uvlayer_name)==0) stupid_uvmenu_var = i+1;
+					sprintf(strtmp2, "|%s%%x%d", layer->name, i+1);
+					strcat(strtmp, strtmp2);
+					layer++;
+				}
+				
+				/*there is no uvlayer defined, or else it was deleted.  Assign active layer,
+				  then recalc modifiers.*/
+				if (stupid_uvmenu_var == -1) {
+					if (CustomData_get_active_layer_index(fdata, CD_MTFACE) != -1) {
+						stupid_uvmenu_var = 1;					
+						layer = fdata->layers;
+						for (i=0; i<CustomData_get_active_layer_index(fdata, CD_MTFACE); i++, layer++) {
+							if (layer->type==CD_MTFACE) stupid_uvmenu_var++;
+						}
+						strcpy(dmd->uvlayer_name, layer->name);
+						
+						/*update the modifiers*/
+						do_modifier_panels(B_MODIFIER_RECALC);
+					} else {
+						/* ok we have no uv layers, so make sure menu button knows that.*/
+						stupid_uvmenu_var = 0;
+					}
+				}
+				
+				but = uiDefButI(block, MENU, B_MODIFIER_RECALC, strtmp,
+			          lx, (cy -= 19), buttonWidth, 19, &stupid_uvmenu_var,
+			          0.0, 1.0, 0, 0, "Set the UV layer to use");
+				
+				uiButSetFunc(but, set_displace_uvlayer, dmd, &fdata->layers[CustomData_get_layer_index(fdata, CD_MTFACE)]);
+			}
 			if(dmd->texmapping == MOD_DISP_MAP_OBJECT) {
 				uiDefIDPoinBut(block, test_obpoin_but, ID_OB, B_CHANGEDEP,
 				               "Ob: ", lx, (cy -= 19), buttonWidth, 19,