[hdPrman] Consolidate and improve motion blur handling

Rewrites the velocity motion blur scene index plugin to handle all types of motion blur processing for hdPrman. The plugin is renamed to HdPrman_MotionBlurSceneIndexPlugin, and redundant motion blur processing code previously scattered throughout hdPrman is removed.

The revised motion blur scene index plugin is exclusively responsible for reshaping data sources for motion blur in hdPrman. No other part of hdPrman needs to concern itself with questions of whether and how to apply motion blur. Downstream consumers need only sample data sources to receive the correct number of samples. Tests are added to explicitly test transform blur (and blurScale, which was not previously applied to transform blur) on geometry and cameras.

The velocity blur handling portions of the plugin have been expanded to support velocity blur on point instancers. However, since hdPrman currently does not support constant primvars on point instancers, the plugin is unable to see authored velocities or angularVelocities and so cannot apply velocity blur to point instancers yet. Accordingly, no test of this functionality has been added. This will be rectified in follow-up work.

Note that in 2294852, we introduced a change that affected all non-points primvars with authored time samples. With that change, such primvars were sampled once at the midpoint of the requested interval. That behavior has been reverted. Non-blurable primvars are sampled at offset 0 regardless of interval to conform to the USDMotionAPI specification.

Support for USD versions < 22.05 and Prman versions < 25.0 is removed from the affected files. Likewise, gating on the presence of the motion blur scene index plugin is also removed, since it is always loaded for USD versions >= 22.05.

(Internal change: 2305710)
(Internal change: 2305831)

third_party/renderman-25/plugin/hdPrman/CMakeLists.txt

@@ -125,7 +125,7 @@ pxr_plugin(${PXR_PACKAGE}
         rileyRenderTargetPrim
         terminalSceneIndexObserver
         utils
-        velocityMotionBlurSceneIndexPlugin
+        motionBlurSceneIndexPlugin
         virtualStructResolvingSceneIndex
 
     PUBLIC_HEADERS

third_party/renderman-25/plugin/hdPrman/basisCurves.cpp

@@ -28,13 +28,8 @@
 #include "hdPrman/material.h"
 #include "hdPrman/rixStrings.h"
 #include "pxr/imaging/hd/basisCurvesTopology.h"
-#include "pxr/base/gf/matrix4f.h"
-#include "pxr/base/gf/matrix4d.h"
 
-#include "Riley.h"
 #include "RiTypesHelper.h"
-#include "RixShadingUtils.h"
-#include "RixPredefinedStrings.hpp"
 
 PXR_NAMESPACE_OPEN_SCOPE
 
@@ -150,18 +145,12 @@ HdPrman_BasisCurves::_ConvertGeometry(HdPrman_RenderParam *renderParam,
 
     // Points
     float primvarTime = 0.0f;
-    if( HdPrman_RenderParam::HasSceneIndexPlugin(
-            HdPrmanPluginTokens->velocityBlur) ) {
-        HdPrman_ConvertPointsPrimvar(
-            sceneDelegate,
-            id,
-            renderParam->GetShutterInterval(),
-            primvars,
-            vertexPrimvarCount);
-    } else {
-        primvarTime = renderParam->ConvertPositions(
-            sceneDelegate, id, vertexPrimvarCount, primvars);
-    }
+    HdPrman_ConvertPointsPrimvar(
+        sceneDelegate,
+        id,
+        renderParam->GetShutterInterval(),
+        primvars,
+        vertexPrimvarCount);
 
     // Set element ID.  Overloaded use of "__faceIndex" to support picking...
     std::vector<int32_t> elementId(numCurves);

third_party/renderman-25/plugin/hdPrman/debugCodes.cpp

@@ -49,6 +49,7 @@ TF_REGISTRY_FUNCTION(TfDebug)
         "computations.");
     TF_DEBUG_ENVIRONMENT_SYMBOL(HDPRMAN_TERMINAL_SCENE_INDEX_OBSERVER,
         "Debug logging for HdPrman terminal scene index observer.");
+    TF_DEBUG_ENVIRONMENT_SYMBOL(HDPRMAN_MOTION_BLUR, "Motion blur");
 }
 
 PXR_NAMESPACE_CLOSE_SCOPE

third_party/renderman-25/plugin/hdPrman/debugCodes.h

@@ -42,7 +42,8 @@ TF_DEBUG_CODES(
     HDPRMAN_MESHLIGHT,
     HDPRMAN_RENDER_SETTINGS,
     HDPRMAN_RENDER_PASS,
-    HDPRMAN_TERMINAL_SCENE_INDEX_OBSERVER
+    HDPRMAN_TERMINAL_SCENE_INDEX_OBSERVER,
+    HDPRMAN_MOTION_BLUR
 );
 
 PXR_NAMESPACE_CLOSE_SCOPE

third_party/renderman-25/plugin/hdPrman/gprim.h

@@ -25,7 +25,6 @@
 #define EXT_RMANPKG_25_0_PLUGIN_RENDERMAN_PLUGIN_HD_PRMAN_GPRIM_H
 
 #include "pxr/pxr.h"
-#include "pxr/imaging/hd/enums.h"
 #include "pxr/usd/sdf/types.h"
 #include "pxr/base/gf/matrix4d.h"
 
@@ -37,8 +36,6 @@
 #include "hdPrman/utils.h"
 
 #include "Riley.h"
-#include "RixShadingUtils.h"
-#include "RixPredefinedStrings.hpp"
 
 PXR_NAMESPACE_OPEN_SCOPE
 
@@ -181,18 +178,6 @@ HdPrman_Gprim<BASE>::Sync(HdSceneDelegate* sceneDelegate,
     HdTimeSampleArray<GfMatrix4d, HDPRMAN_MAX_TIME_SAMPLES> xf;
     sceneDelegate->SampleTransform(id, &xf);
 
-    // If blur is explicitly disabled, use single time 0 sample
-    const bool enableMotionBlur =
-        param->IsMotionBlurEnabled() &&
-        HdPrman_IsMotionBlurPrimvarEnabled(sceneDelegate, id) &&
-        HdPrman_GetNumXformSamples(sceneDelegate, id) >= 2;
-
-    if (!enableMotionBlur) {
-        xf.values[0] = xf.Resample(0.f);
-        xf.times[0] = 0.f;
-        xf.Resize(1);
-    }
-
     // Update visibility so thet rprim->IsVisible() will work in render pass
     if (HdChangeTracker::IsVisibilityDirty(*dirtyBits, id)) {
         BASE::_UpdateVisibility(sceneDelegate, dirtyBits);

third_party/renderman-25/plugin/hdPrman/mesh.cpp

@@ -25,25 +25,14 @@
 #include "hdPrman/mesh.h"
 #include "hdPrman/renderParam.h"
 #include "hdPrman/coordSys.h"
-#include "hdPrman/instancer.h"
 #include "hdPrman/material.h"
 #include "hdPrman/rixStrings.h"
-#include "pxr/base/gf/matrix4d.h"
-#include "pxr/base/gf/matrix4f.h"
-#include "pxr/base/gf/vec2f.h"
-#include "pxr/base/gf/vec3f.h"
-#include "pxr/base/gf/vec4f.h"
-#include "pxr/imaging/hd/coordSys.h"
 #include "pxr/imaging/hd/meshTopology.h"
-#include "pxr/imaging/hd/meshUtil.h"
 #include "pxr/imaging/pxOsd/subdivTags.h"
 #include "pxr/imaging/pxOsd/tokens.h"
 #include "pxr/usd/usdRi/rmanUtilities.h"
 
-#include "Riley.h"
 #include "RiTypesHelper.h"
-#include "RixShadingUtils.h"
-#include "RixPredefinedStrings.hpp"
 
 #include <algorithm>
 
@@ -169,18 +158,12 @@ HdPrman_Mesh::_ConvertGeometry(HdPrman_RenderParam *renderParam,
     // Point positions (P)
     //
     float primvarTime = 0.0f;
-    if( HdPrman_RenderParam::HasSceneIndexPlugin(
-            HdPrmanPluginTokens->velocityBlur) ) {
-        HdPrman_ConvertPointsPrimvar(
-            sceneDelegate,
-            id,
-            renderParam->GetShutterInterval(),
-            primvars,
-            npoints);
-    } else {
-        primvarTime = renderParam->ConvertPositions(
-            sceneDelegate, id, npoints, primvars);
-    }
+    HdPrman_ConvertPointsPrimvar(
+        sceneDelegate,
+        id,
+        renderParam->GetShutterInterval(),
+        primvars,
+        npoints);
     // Topology.
     primvars.SetIntegerDetail(RixStr.k_Ri_nvertices, nverts.cdata(),
                               RtDetailType::k_uniform);