add udim example of a simple cube and fix GraphEditor

Author: ld-kerley

resources/Geometry/udim_cube.obj

@@ -0,0 +1,41 @@
+# This file uses centimeters as units for non-parametric coordinates.
+g
+v -0.500000 -0.500000 0.500000
+v 0.500000 -0.500000 0.500000
+v -0.500000 0.500000 0.500000
+v 0.500000 0.500000 0.500000
+v -0.500000 0.500000 -0.500000
+v 0.500000 0.500000 -0.500000
+v -0.500000 -0.500000 -0.500000
+v 0.500000 -0.500000 -0.500000
+vt 0.99 0.01
+vt 0.99 1.01
+vt 1.01 0.01
+vt 2.01 0.99
+vt 2.01 1.01
+vt 1.99 0.99
+vt 1.01 1.01
+vt 2.99 2.01
+vt 1.01 1.99
+vt 1.99 1.99
+vt 2.99 0.01
+vt 2.99 0.99
+vt 0.01 0.01
+vt 0.01 0.99
+vt 2.01 0.01
+vt 0.99 1.99
+vt 1.99 0.01
+vt 0.01 1.01
+vt 0.01 1.99
+vt 0.99 0.99
+vt 2.01 2.01
+vt 1.99 1.01
+vt 1.01 0.99
+vt 2.99 1.
+g
+f 1/18 2/2 4/16 3/19
+f 3/3 4/17 6/6 5/23
+f 5/5 6/24 8/8 7/21
+f 7/7 8/22 2/10 1/9
+f 2/15 8/11 6/12 4/4
+f 7/13 1/1 3/20 5/14

resources/Images/grid_udim/grid.1001.png

@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<materialx version="1.38">
+  <image name="image_color" type="color3">
+    <input name="file" type="filename" value="resources/Images/grid_udim/grid.<UDIM>.png" colorspace="srgb_texture" />
+  </image>
+  <geominfo name="cube_geom" geom="/">
+    <geomprop name="udimset" type="stringarray" value="1001, 1002, 1003, 1011, 1012, 1013" />
+  </geominfo>
+  <standard_surface name="cube_shader" type="surfaceshader">
+    <input name="base_color" type="color3" nodename="image_color" />
+  </standard_surface>
+  <surfacematerial name="cube_material" type="material">
+    <input name="surfaceshader" type="surfaceshader" nodename="cube_shader" />
+  </surfacematerial>
+</materialx>

resources/Images/grid_udim/grid.1002.png

@@ -403,15 +403,6 @@ void RenderView::updateMaterials(mx::TypedElementPtr typedElem)
         // Check for any udim set.
         mx::ValuePtr udimSetValue = _document->getGeomPropValue(mx::UDIM_SET_PROPERTY);
 
-        // Skip material nodes without upstream shaders.
-        mx::NodePtr node = typedElem ? typedElem->asA<mx::Node>() : nullptr;
-        if (node &&
-            node->getCategory() == mx::SURFACE_MATERIAL_NODE_STRING &&
-            mx::getShaderNodes(node).empty())
-        {
-            typedElem = nullptr;
-        }
-
         // Create new materials.
         if (!typedElem)
         {
@@ -422,6 +413,15 @@ void RenderView::updateMaterials(mx::TypedElementPtr typedElem)
             }
         }
 
+        // Skip material nodes without upstream shaders.
+        mx::NodePtr node = typedElem ? typedElem->asA<mx::Node>() : nullptr;
+        if (node &&
+            node->getCategory() == mx::SURFACE_MATERIAL_NODE_STRING &&
+            mx::getShaderNodes(node).empty())
+        {
+            typedElem = nullptr;
+        }
+
         mx::TypedElementPtr udimElement = nullptr;
         mx::NodePtr materialNode = nullptr;
         if (typedElem)