Draw MM native ImagePlanes in background pass.

This allows surfaces to be hidden-line wireframe, with an MM ImagePlane
behind it.

Before this change, Maya native ImagePlanes were drawn behind "hidden
line" surfaces, but now both native and MM ImagePlanes work as expected.

include/mmSolver/nodeTypeIds.h

@@ -127,6 +127,9 @@
 
 #define MM_IMAGE_PLANE_SHAPE_TYPE_ID 0x0012F187
 #define MM_IMAGE_PLANE_SHAPE_TYPE_NAME "mmImagePlaneShape"
+#define MM_IMAGE_PLANE_SHAPE_NODE_CLASSIFY                                  \
+    "auxiliary/camera:geometry/camera:imageplane:drawdb/geometry/mmSolver/" \
+    "imagePlane"
 #define MM_IMAGE_PLANE_SHAPE_DRAW_CLASSIFY "drawdb/geometry/mmSolver/imagePlane"
 #define MM_IMAGE_PLANE_SHAPE_DRAW_REGISTRANT_ID "mmImagePlaneShape"
 #define MM_IMAGE_PLANE_SHAPE_SELECTION_TYPE_NAME "mmImagePlaneShapeSelection"

src/mmSolver/pluginMain.cpp

@@ -314,7 +314,7 @@ MStatus initializePlugin(MObject obj) {
     const MString markerClassification = MM_MARKER_DRAW_CLASSIFY;
     const MString bundleClassification = MM_BUNDLE_DRAW_CLASSIFY;
     const MString imagePlaneShapeClassification =
-        MM_IMAGE_PLANE_SHAPE_DRAW_CLASSIFY;
+        MM_IMAGE_PLANE_SHAPE_NODE_CLASSIFY;
     const MString skyDomeClassification = MM_SKY_DOME_DRAW_CLASSIFY;
     const MString lineClassification = MM_LINE_DRAW_CLASSIFY;
     REGISTER_LOCATOR_NODE(plugin, mmsolver::MarkerShapeNode::nodeName(),

src/mmSolver/render/RenderOverride.cpp

@@ -312,13 +312,35 @@ MStatus RenderOverride::updateRenderOperations() {
     m_op_names[kSceneManipulatorPass] = "mmRenderer_SceneRender_Manipulator";
     m_op_names[kPresentOp] = "mmRenderer_PresentTarget";
 
+    // Draw these objects for transparency.
+    auto wire_draw_object_types =
+        ~(MHWRender::MFrameContext::kExcludeMeshes |
+          MHWRender::MFrameContext::kExcludeNurbsCurves |
+          MHWRender::MFrameContext::kExcludeNurbsSurfaces |
+          MHWRender::MFrameContext::kExcludeSubdivSurfaces);
+
+    // Draw all non-geometry normally.
+    auto non_wire_draw_object_types =
+        ((~wire_draw_object_types) |
+         MHWRender::MFrameContext::kExcludeImagePlane |
+         MHWRender::MFrameContext::kExcludePluginShapes);
+
+    // What objects types to draw for depth buffer?
+    auto depth_draw_object_types =
+        wire_draw_object_types | MHWRender::MFrameContext::kExcludeImagePlane;
+
+    // Draw image planes in the background always.
+    auto bg_draw_object_types =
+        ~(MHWRender::MFrameContext::kExcludeImagePlane |
+          MHWRender::MFrameContext::kExcludePluginShapes);
+
     SceneRender *sceneOp = nullptr;
 
     // Depth pass.
     sceneOp = new SceneRender(m_op_names[kSceneDepthPass]);
     sceneOp->setViewRectangle(rect);
     sceneOp->setSceneFilter(MHWRender::MSceneRender::kRenderShadedItems);
-    sceneOp->setExcludeTypes(MHWRender::MFrameContext::kExcludeImagePlane);
+    sceneOp->setExcludeTypes(depth_draw_object_types);
     sceneOp->setDisplayModeOverride(display_mode_shaded);
     // do not override objects to be drawn.
     sceneOp->setDoSelectable(false);
@@ -330,6 +352,7 @@ MStatus RenderOverride::updateRenderOperations() {
     sceneOp = new SceneRender(m_op_names[kSceneBackgroundPass]);
     sceneOp->setViewRectangle(rect);
     sceneOp->setSceneFilter(MHWRender::MSceneRender::kRenderShadedItems);
+    // sceneOp->setExcludeTypes(bg_draw_object_types);
     // override drawn objects to only image planes under cameras.
     sceneOp->setDoSelectable(true);
     sceneOp->setDoBackground(true);
@@ -356,7 +379,7 @@ MStatus RenderOverride::updateRenderOperations() {
     sceneOp = new SceneRender(m_op_names[kSceneWireframePass]);
     sceneOp->setViewRectangle(rect);
     sceneOp->setSceneFilter(MHWRender::MSceneRender::kRenderUIItems);
-    sceneOp->setExcludeTypes(MHWRender::MFrameContext::kExcludeManipulators);
+    sceneOp->setExcludeTypes(wire_draw_object_types);
     sceneOp->setDisplayModeOverride(display_mode_wireframe);
     // do not override objects to be drawn.
     sceneOp->setDoSelectable(false);
@@ -389,7 +412,7 @@ MStatus RenderOverride::updateRenderOperations() {
     sceneOp = new SceneRender(m_op_names[kSceneManipulatorPass]);
     sceneOp->setViewRectangle(rect);
     sceneOp->setSceneFilter(MHWRender::MSceneRender::kRenderUIItems);
-    sceneOp->setExcludeTypes(~MHWRender::MFrameContext::kExcludeManipulators);
+    sceneOp->setExcludeTypes(non_wire_draw_object_types);
     sceneOp->setDoSelectable(false);
     sceneOp->setDoBackground(false);
     sceneOp->setClearMask(clear_mask_none);

src/mmSolver/render/SceneRender.cpp

@@ -123,8 +123,11 @@ SceneRender::postEffectsOverride() {
 const MSelectionList *SceneRender::objectSetOverride() {
     // If m_do_selectable is false and m_do_background is false: do
     // not override.
-    mSelectionList.clear();
-    if (m_do_selectable && m_do_background) {
+    m_selection_list.clear();
+    if (!m_do_selectable && !m_do_background) {
+        // This is the most common branch, so it is first.
+        return nullptr;
+    } else if (m_do_selectable && m_do_background) {
         // If m_do_selectable is true and m_do_background is true:
         // override drawn objects to only image planes under cameras.
         MItDag it;
@@ -137,24 +140,29 @@ const MSelectionList *SceneRender::objectSetOverride() {
                 if (path.pathCount() < 2) {
                     continue;
                 }
-                mSelectionList.add(path);
+                m_selection_list.add(path);
+            } else if (item.apiType() == MFn::kPluginLocatorNode) {
+                MDagPath path;
+                it.getPath(path);
+                m_selection_list.add(path);
             }
         }
-        return &mSelectionList;
+        return &m_selection_list;
     } else if (m_do_selectable && !m_do_background) {
         // If m_do_selectable is true and m_do_background is false:
         // override drawn objects to all image planes not under cameras.
         MItDag it;
         it.traverseUnderWorld(false);
         for (it.reset(); !it.isDone(); it.next()) {
             auto item = it.currentItem();
-            if (item.hasFn(MFn::kImagePlane)) {
+            if (item.hasFn(MFn::kImagePlane) ||
+                (item.apiType() == MFn::kPluginLocatorNode)) {
                 MDagPath path;
                 it.getPath(path);
-                mSelectionList.add(path);
+                m_selection_list.add(path);
             }
         }
-        return &mSelectionList;
+        return &m_selection_list;
     }
     return nullptr;
 }

src/mmSolver/render/SceneRender.h

@@ -111,7 +111,8 @@ class SceneRender : public MHWRender::MSceneRender {
     void setDoBackground(const bool value) { m_do_background = value; }
 
 protected:
-    MSelectionList mSelectionList;
+    // Objects Set override. Override which objects are drawn.
+    MSelectionList m_selection_list;
 
     // 3D viewport panel name, if available
     MString m_panel_name;