Texture painting:

Do not generate materials/images/UVs if they are missing.

Now we spawn a panel ("Missing Data") with operators to generate the missing data and
pop a warning if user tries to paint without them.

The reason we have reverted this is that it is too easy to end up with more textures
than we wanted. It was impossible to enter texture paint without having textures added,
and code makes too many assumptions about what user may want.

Discussed during Sunday's meeting.

This might be a candidate for 2.72a but I'm not sure how other artists will take this
(and how refined and crash-free it is), better make a few iterations first.

And for interested parties...test please, don't wait until after a release to poke with such issues.

Also, add slot operator now adds a new unconnected image node in cycles. Only
used in the "Missing Data" panel. This should be a separate commit but I am squashing it into the same commit because
it relies too much on changes done here and can be reverted easily if complainstorm occurs again.

2 files changed, 74 insertions, 13 deletions

diff --git a/release/scripts/startup/bl_ui/properties_paint_common.py b/release/scripts/startup/bl_ui/properties_paint_common.py
index 81bbc7754a7..f1042856e4c 100644
--- a/release/scripts/startup/bl_ui/properties_paint_common.py
+++ b/release/scripts/startup/bl_ui/properties_paint_common.py
@@ -36,7 +36,10 @@ class UnifiedPaintPanel():
         elif context.weight_paint_object:
             return toolsettings.weight_paint
         elif context.image_paint_object:
-            return toolsettings.image_paint
+            if (toolsettings.image_paint and toolsettings.image_paint.detect_data()):
+                return toolsettings.image_paint
+
+            return None
         elif context.particle_edit_object:
             return toolsettings.particle_edit
 
diff --git a/release/scripts/startup/bl_ui/space_view3d_toolbar.py b/release/scripts/startup/bl_ui/space_view3d_toolbar.py
index ffd4299bc39..213bfd9d808 100644
--- a/release/scripts/startup/bl_ui/space_view3d_toolbar.py
+++ b/release/scripts/startup/bl_ui/space_view3d_toolbar.py
@@ -775,6 +775,65 @@ class View3DPaintPanel(UnifiedPaintPanel):
     bl_space_type = 'VIEW_3D'
     bl_region_type = 'TOOLS'
 
+class VIEW3D_PT_imapaint_tools_missing(Panel, View3DPaintPanel):
+    bl_category = "Tools"
+    bl_label = "Missing Data"
+
+    @classmethod
+    def poll(cls, context):
+        toolsettings = context.tool_settings.image_paint
+        return context.image_paint_object and not toolsettings.detect_data()
+
+    def draw(self, context):
+        layout = self.layout
+        toolsettings = context.tool_settings.image_paint
+
+        col = layout.column()
+        col.label("Missing Data", icon='ERROR')
+        if toolsettings.missing_uvs:
+            col.separator()
+            col.label("Missing UVs", icon='INFO')
+            col.label("Unwrap the mesh in edit mode or generate a simple UVs")
+            col.operator("mesh.uv_texture_add", text="Add Simple UVs")
+    
+        if toolsettings.mode == 'MATERIAL':
+            if toolsettings.missing_materials:
+                col.separator()
+                col.label("Missing Materials", icon='INFO')
+                col.label("Add a material and paint slot below")
+                col.operator_menu_enum("paint.add_texture_paint_slot", "type", text="Add Paint Slot")
+                   
+            elif toolsettings.missing_texture:
+                ob = context.active_object
+                mat = ob.active_material
+
+                col.separator()
+                if mat:
+                    col.label("Missing Texture Slots", icon='INFO')
+                    col.label("Add a paint slot below")
+                    col.operator_menu_enum("paint.add_texture_paint_slot", "type", text="Add Paint Slot")
+                else:
+                    col.label("Missing Materials", icon='INFO')
+                    col.label("Add a material and paint slot below")
+                    col.operator_menu_enum("paint.add_texture_paint_slot", "type", text="Add Paint Slot")
+ 
+
+        elif toolsettings.mode == 'IMAGE':
+            if toolsettings.missing_texture:
+                col.separator()
+                col.label("Missing Canvas", icon='INFO')
+                col.label("Add or assign a canvas image below")
+                col.label("Canvas Image")
+                col.template_ID(toolsettings, "canvas")
+                col.operator("image.new", text="New").gen_context = 'PAINT_CANVAS'
+
+        if toolsettings.missing_stencil:
+            col.separator()
+            col.label("Missing Stencil", icon='INFO')
+            col.label("Add or assign a stencil image below")
+            col.label("Stencil Image")
+            col.template_ID(toolsettings, "stencil_image")
+            col.operator("image.new", text="New").gen_context = 'PAINT_STENCIL'
 
 class VIEW3D_PT_tools_brush(Panel, View3DPaintPanel):
     bl_category = "Tools"
@@ -1072,8 +1131,9 @@ class VIEW3D_PT_slots_projectpaint(View3DPanel, Panel):
         elif settings.mode == 'IMAGE':
             mesh = ob.data
             uv_text = mesh.uv_textures.active.name if mesh.uv_textures.active else ""
-            col.label("Image")
+            col.label("Canvas Image")
             col.template_ID(settings, "canvas")
+            col.operator("image.new", text="New").gen_context = 'PAINT_CANVAS'
             col.label("UV Map")
             col.menu("VIEW3D_MT_tools_projectpaint_uvlayer", text=uv_text, translate=False)
 
@@ -1111,9 +1171,10 @@ class VIEW3D_PT_stencil_projectpaint(View3DPanel, Panel):
         col.label("UV Map")
         col.menu("VIEW3D_MT_tools_projectpaint_stencil", text=stencil_text, translate=False)
 
-        col.label("Image")
-        row = col.row(align=True)
-        row.template_ID(ipaint, "stencil_image")
+        col.label("Stencil Image")
+        col.template_ID(ipaint, "stencil_image")
+        col.operator("image.new", text="New").gen_context = 'PAINT_STENCIL'
+
  
         col.label("Visualization")
         row = col.row(align=True)
@@ -1211,7 +1272,7 @@ class VIEW3D_PT_tools_brush_texture(Panel, View3DPaintPanel):
         brush_texture_settings(col, brush, context.sculpt_object)
 
 
-class VIEW3D_PT_tools_mask_texture(View3DPanel, Panel):
+class VIEW3D_PT_tools_mask_texture(View3DPanel, View3DPaintPanel):
     bl_category = "Tools"
     bl_context = "imagepaint"
     bl_label = "Texture Mask"
@@ -1219,8 +1280,8 @@ class VIEW3D_PT_tools_mask_texture(View3DPanel, Panel):
 
     @classmethod
     def poll(cls, context):
-        brush = context.tool_settings.image_paint.brush
-        return (context.image_paint_object and brush)
+        settings = cls.paint_settings(context)
+        return (settings and settings.image_paint.brush and context.image_paint_object and brush)
 
     def draw(self, context):
         layout = self.layout
@@ -1475,11 +1536,8 @@ class VIEW3D_PT_tools_brush_appearance(Panel, View3DPaintPanel):
 
     @classmethod
     def poll(cls, context):
-        toolsettings = context.tool_settings
-        return ((context.sculpt_object and toolsettings.sculpt) or
-                (context.vertex_paint_object and toolsettings.vertex_paint) or
-                (context.weight_paint_object and toolsettings.weight_paint) or
-                (context.image_paint_object and toolsettings.image_paint))
+        settings = cls.paint_settings(context)
+        return settings
 
     def draw(self, context):
         layout = self.layout