handle vertex interpolated uvs on bspline curves

CHANGELOG.md

@@ -12,6 +12,7 @@
 - [usd#1770](https://github.com/Autodesk/arnold-usd/issues/1770) - Fix exr driver always rendering float with husk when productType is arnold
 - [usd#1772](https://github.com/Autodesk/arnold-usd/issues/1772) - RectLight texture uvs are now consistent between husk, kick and other renderers.
 - [usd#1776](https://github.com/Autodesk/arnold-usd/issues/1776) - Fix incorrect PointInstancer instance orientations in the render delegate.
+- [usd#1769](https://github.com/Autodesk/arnold-usd/issues/1769) - Fix curve uvs when they are vertex interpolated.
 
 ## [7.2.5.0] - 2023-12-13
 

libs/render_delegate/basis_curves.cpp

@@ -53,6 +53,30 @@ namespace {
 
 } // namespace
 
+
+// Function to convert a GfVec3f array to a GfVec2f array, skipping the last component.
+// It could be used more generally later by registering it as a VtValue Cast:
+//
+//     VtValue::RegisterCast<VtVec3fArray, VtVec2fArray>(&Vec3fToVec2f);
+//
+//  then simply call the Cast function as follows:
+//
+//     value = VtValue::Cast<VtVec2fArray>(desc.value);
+//
+VtValue Vec3fToVec2f(VtValue const &val) {
+    if (val.IsHolding<VtVec3fArray>()) {
+        const auto& vec3 = val.UncheckedGet<VtVec3fArray>();
+        VtVec2fArray vec2(vec3.size());
+        std::transform(
+            vec3.cbegin(), vec3.cend(), vec2.begin(),
+            [](const GfVec3f& in) -> GfVec2f {
+                return {in[0], in[1]};
+            });
+        return VtValue::Take(vec2);
+    }
+    return {};
+}
+
 #if PXR_VERSION >= 2102
 HdArnoldBasisCurves::HdArnoldBasisCurves(HdArnoldRenderDelegate* delegate, const SdfPath& id)
     : HdArnoldRprim<HdBasisCurves>(str::curves, delegate, id), _interpolation(HdTokens->linear)
@@ -187,58 +211,45 @@ void HdArnoldBasisCurves::Sync(
                 }
                 continue;
             }
+
+            // The curves node only knows the "uvs" parameter, so we have to rename the attribute
+            TfToken arnoldAttributeName = primvar.first;
+            auto value = desc.value;
             if (primvar.first == str::t_uv || primvar.first == str::t_st) {
-                // This is either a VtVec2fArray or VtVec3fArray (in Solaris).
-                if (desc.value.IsHolding<VtVec2fArray>()) {
-                    const auto& v = desc.value.UncheckedGet<VtVec2fArray>();
-                    AiNodeSetArray(
-                        GetArnoldNode(), str::uvs, AiArrayConvert(v.size(), 1, AI_TYPE_VECTOR2, v.data()));
-                    continue;
-                }
+                arnoldAttributeName = str::t_uvs;
+                // Special case if the uvs attribute has 3 dimensions
                 if (desc.value.IsHolding<VtVec3fArray>()) {
-                    const auto& v = desc.value.UncheckedGet<VtVec3fArray>();
-                    auto* arr = AiArrayAllocate(v.size(), 1, AI_TYPE_VECTOR2);
-                    if (!v.empty()) {
-                        std::transform(
-                            v.begin(), v.end(), static_cast<GfVec2f*>(AiArrayMap(arr)),
-                            [](const GfVec3f& in) -> GfVec2f {
-                                return {in[0], in[1]};
-                            });
-                        AiArrayUnmap(arr);
-                    }
-                    AiNodeSetArray(GetArnoldNode(), str::uvs, arr);
-                    continue;
-                } 
+                    value = Vec3fToVec2f(desc.value);
+                }
             }
 
             if (desc.interpolation == HdInterpolationConstant) {
                 // We skip reading the basis for now as it would require remapping the vertices, widths and
                 // all the primvars.
                 if (primvar.first != _tokens->basis) {
                     HdArnoldSetConstantPrimvar(
-                        GetArnoldNode(), primvar.first, desc.role, desc.value, &_visibilityFlags, &_sidednessFlags,
+                        GetArnoldNode(), arnoldAttributeName, desc.role, value, &_visibilityFlags, &_sidednessFlags,
                         nullptr, GetRenderDelegate());
                 }
             } else if (desc.interpolation == HdInterpolationUniform) {
-                HdArnoldSetUniformPrimvar(GetArnoldNode(), primvar.first, desc.role, desc.value, GetRenderDelegate());
+                HdArnoldSetUniformPrimvar(GetArnoldNode(), arnoldAttributeName, desc.role, value, GetRenderDelegate());
             } else if (desc.interpolation == HdInterpolationVertex || desc.interpolation == HdInterpolationVarying) {
                 if (primvar.first == HdTokens->points) {
-                    HdArnoldSetPositionFromValue(GetArnoldNode(), str::points, desc.value);
+                    HdArnoldSetPositionFromValue(GetArnoldNode(), str::points, value);
                 } else if (primvar.first == HdTokens->normals) {
                     if (_interpolation == HdTokens->linear)
                         AiMsgWarning("%s : Orientations not supported on linear curves", AiNodeGetName(GetArnoldNode()));
                     else
-                        curvesData.SetOrientationFromValue(GetArnoldNode(), desc.value);
+                        curvesData.SetOrientationFromValue(GetArnoldNode(), value);
                 } else {
-                    auto value = desc.value;
                     // For pinned curves, vertex interpolation primvars shouldn't be remapped
                     if (_interpolation != HdTokens->linear && 
                         !(isPinned && desc.interpolation == HdInterpolationVertex)) {
                         curvesData.RemapCurvesVertexPrimvar<
                             bool, VtUCharArray::value_type, unsigned int, int, float, GfVec2f, GfVec3f, GfVec4f,
                             std::string, TfToken, SdfAssetPath>(value);
                     }
-                    HdArnoldSetVertexPrimvar(GetArnoldNode(), primvar.first, desc.role, value, GetRenderDelegate());
+                    HdArnoldSetVertexPrimvar(GetArnoldNode(), arnoldAttributeName, desc.role, value, GetRenderDelegate());
                 }
             }
         }

testsuite/groups

@@ -40,7 +40,7 @@ darwin:
 # SPECIAL TEST GROUPS #
 #######################
 # Tests that can be run in hydra mode
-hydra: test_0000 test_0001 test_0002 test_0003 test_0004 test_0005 test_0006 test_0007 test_0008 test_0009 test_0010 test_0011 test_0012 test_0014 test_0016 test_0017 test_0018 test_0019 test_0020 test_0021 test_0022 test_0023 test_0024 test_0025 test_0026 test_0027 test_0028 test_0029 test_0030 test_0031 test_0032 test_0033 test_0034 test_0038 test_0041 test_0046 test_0048 test_0049 test_0055 test_0112 test_0130 test_0132 test_0133 test_0135 test_0139 test_0140 test_0141 test_0142 test_0143 test_0144 test_0145 test_0148 test_0149 test_0150 test_0151 test_0158 test_0159 test_0161 test_0162 test_0163 test_0164 test_0165 test_0166 test_0168 test_0169 test_0170 test_0171 test_0172 test_0173 test_0174 test_0175 test_0177 test_0178 test_0180 test_0183 test_0184 test_0186 test_0187 test_0188 test_0189 test_0191 test_0194 test_0195 test_0196 test_0197 test_0198 test_0200 test_0201 test_0202 test_0204 test_0205 test_0206 test_0207 test_0215 test_0216 test_0217 test_0219 test_0220 test_0221 test_0222 test_0223 test_0225 test_0227 test_0228 test_0229 test_0230 test_0299 test_0232 test_0233 test_0234 test_0238 test_0239 test_0240 test_0242 test_0243 test_0244 test_0245 test_0739 test_1181 test_1204 test_1209 test_1225 test_1245 test_1262 test_1294 test_1309 test_1311 test_1313 test_1333 test_1334 test_1346 test_1416 test_1420 test_1426 test_1427.3 test_1430 test_1433 test_1435 test_1438 test_1457 test_1486 test_1499 test_1524 test_1525 test_1530 test_1535 test_1538 test_1546 test_1550 test_1567 test_1588 test_1590 test_1593 test_1607 test_1613 test_1625 test_1632 test_1654  test_1657 test_1678 test_1718 test_1726 test_1735 test_1772
+hydra: test_0000 test_0001 test_0002 test_0003 test_0004 test_0005 test_0006 test_0007 test_0008 test_0009 test_0010 test_0011 test_0012 test_0014 test_0016 test_0017 test_0018 test_0019 test_0020 test_0021 test_0022 test_0023 test_0024 test_0025 test_0026 test_0027 test_0028 test_0029 test_0030 test_0031 test_0032 test_0033 test_0034 test_0038 test_0041 test_0046 test_0048 test_0049 test_0055 test_0112 test_0130 test_0132 test_0133 test_0135 test_0139 test_0140 test_0141 test_0142 test_0143 test_0144 test_0145 test_0148 test_0149 test_0150 test_0151 test_0158 test_0159 test_0161 test_0162 test_0163 test_0164 test_0165 test_0166 test_0168 test_0169 test_0170 test_0171 test_0172 test_0173 test_0174 test_0175 test_0177 test_0178 test_0180 test_0183 test_0184 test_0186 test_0187 test_0188 test_0189 test_0191 test_0194 test_0195 test_0196 test_0197 test_0198 test_0200 test_0201 test_0202 test_0204 test_0205 test_0206 test_0207 test_0215 test_0216 test_0217 test_0219 test_0220 test_0221 test_0222 test_0223 test_0225 test_0227 test_0228 test_0229 test_0230 test_0299 test_0232 test_0233 test_0234 test_0238 test_0239 test_0240 test_0242 test_0243 test_0244 test_0245 test_0739 test_1181 test_1204 test_1209 test_1225 test_1245 test_1262 test_1294 test_1309 test_1311 test_1313 test_1333 test_1334 test_1346 test_1416 test_1420 test_1426 test_1427.3 test_1430 test_1433 test_1435 test_1438 test_1457 test_1486 test_1499 test_1524 test_1525 test_1530 test_1535 test_1538 test_1546 test_1550 test_1567 test_1588 test_1590 test_1593 test_1607 test_1613 test_1625 test_1632 test_1654  test_1657 test_1678 test_1718 test_1726 test_1735 test_1769 test_1772
 
 
 # Tests in this group will never be executed (you can use it to temporarily disable some tests and/or groups)

testsuite/test_1769/README

@@ -0,0 +1,7 @@
+BSpline curve with vertex interpolated uvs
+
+author: cyril.pichard@autodesk.com 
+
+see #1769
+
+PARAMS: {'scene':'test.usda'}

testsuite/test_1769/data/test.usda

@@ -0,0 +1,83 @@
+#usda 1.0
+(
+    defaultPrim = "sopimport1"
+    endTimeCode = 1
+    framesPerSecond = 24
+    metersPerUnit = 1
+    startTimeCode = 1
+    timeCodesPerSecond = 24
+    upAxis = "Y"
+)
+
+def Xform "sopimport1" (
+    kind = "component"
+)
+{
+    def BasisCurves "curve_0"
+    {
+        uniform token basis = "bspline"
+        int[] curveVertexCounts = [9]
+        float3[] extent = [(0.6149099, 0, 1.2895236), (0.6149099, 0.799, 1.2895236)]
+        point3f[] points = [(0.6149099, 0, 1.2895236), (0.6149099, 0, 1.2895236), (0.6149099, 0, 1.2895236), (0.6149099, 0.19975, 1.2895236), (0.6149099, 0.3995, 1.2895236), (0.6149099, 0.59925, 1.2895236), (0.6149099, 0.799, 1.2895236), (0.6149099, 0.799, 1.2895236), (0.6149099, 0.799, 1.2895236)] (
+            interpolation = "vertex"
+        )
+        texCoord2f[] primvars:st = [(0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809), (0.6537275, 0.8223809)] (
+            interpolation = "vertex"
+        )
+        int[] primvars:st:indices = None
+        uniform token type = "cubic"
+        uniform token wrap = "nonperiodic"
+    }
+}
+
+def Xform "lights"
+{
+    def RectLight "arealight1" (
+        prepend apiSchemas = ["HoudiniViewportLightAPI", "HoudiniViewportGuideAPI"]
+    )
+    {
+        float2 houdini:clippingRange = (0.001, 10000)
+        bool houdini:inviewermenu = 1
+        color3f inputs:color = (1, 1, 1)
+        float inputs:diffuse = 1
+        bool inputs:enableColorTemperature = 0
+        float inputs:exposure = 0
+        float inputs:height = 7.448014
+        float inputs:intensity = 0.1
+        bool inputs:normalize = 0
+        float inputs:specular = 1
+        asset inputs:texture:file = @@
+        float inputs:width = 8.364269
+        rel light:filters = None
+        matrix4d xformOp:transform = ( (-0.02482371480219213, -0.9990594771725642, 0.03555199368674425, 0), (-1.8395864258974326e-12, -0.035562952619954354, -0.9993674381332178, 0), (0.999691844111684, -0.024808012266881785, 0.0008828045915237619, 0), (1.5704420804977417, 0.43900111317634605, 1.7137359082698838, 1) )
+        uniform token[] xformOpOrder = ["xformOp:transform"]
+    }
+}
+
+def Xform "cameras"
+{
+    def Camera "camera1" (
+        prepend apiSchemas = ["HoudiniCameraPlateAPI", "HoudiniViewportGuideAPI"]
+    )
+    {
+        float2 clippingRange = (1, 1000000)
+        float exposure = 0
+        float focalLength = 0.45
+        float focusDistance = 10.78378
+        float fStop = 0
+        float horizontalAperture = 0.20955
+        float horizontalApertureOffset = 0
+        asset houdini:backgroundimage = @@
+        asset houdini:foregroundimage = @@
+        float houdini:guidescale = 1
+        bool houdini:inviewermenu = 1
+        token projection = "perspective"
+        double shutter:close = 0.25
+        double shutter:open = -0.25
+        float verticalAperture = 0.11787187
+        float verticalApertureOffset = 0
+        matrix4d xformOp:transform = ( (0.5250461978776859, -0.0007888840709954176, -0.8510733621469471, 0), (-0.036986569010682126, 0.999033644144815, -0.023743874569022813, 0), (0.8502696535846755, 0.04394491470755142, 0.5245096382949908, 0), (3.7343048332866244, 0.550095433860866, 3.2061258043688006, 1) )
+        uniform token[] xformOpOrder = ["xformOp:transform"]
+    }
+}
+