OGSMOD-7666 - MayaHydra- Try to reproduce the issue using a unit test

test/CMakeLists.txt

@@ -40,24 +40,7 @@ add_subdirectory("RenderingFramework")
 
 add_executable(${_TARGET}
     main.cpp
-    howTos/howTo01_CreateHgiImplementation.cpp
-    howTos/howTo02_CreateOneFramePass.cpp
-    howTos/howTo03_CreateTwoFramePasses.cpp
-    howTos/howTo04_CreateACustomRenderTask.cpp
-    howTos/howTo05_UseSSAORenderTask.cpp
-    howTos/howTo06_UseFXAARenderTask.cpp
-    howTos/howTo07_UseIncludeExclude.cpp
-    howTos/howTo08_UseBoundingBoxSceneIndex.cpp
-    howTos/howTo09_UseWireFrameSceneIndex.cpp
-    howTos/howTo10_CustomListOfTasks.cpp
-    howTos/howTo11_UseSkyDomeTask.cpp
-    tests/composeTaskHelpers.cpp
-    tests/composeTaskHelpers.h
-    tests/testComposeTask.cpp
-    tests/testFramePass.cpp
-    tests/testFramePasses.cpp
-    tests/testSearches.cpp
-    tests/testTaskManager.cpp
+    tests/testMultiSampling.cpp
 )
 
 # Is the generator a multi-config one?

test/RenderingFramework/TestHelpers.h

@@ -76,10 +76,11 @@ namespace TestHelpers
 {
 
 // Some global color definitions.
-const pxr::GfVec4f ColorBlackNoAlpha = pxr::GfVec4f(0.0f, 0.0f, 0.0f, 0.0f);
-const pxr::GfVec4f ColorDarkGrey     = pxr::GfVec4f(0.025f, 0.025f, 0.025f, 1.0f);
-const pxr::GfVec4f ColorYellow       = pxr::GfVec4f(1.0f, 1.0f, 0.0f, 1.0f);
-const pxr::GfVec4f ColorWhite        = pxr::GfVec4f(1.0f, 1.0f, 1.0f, 1.0f);
+const pxr::GfVec4f ColorBlackNoAlpha    = pxr::GfVec4f(0.0f, 0.0f, 0.0f, 0.0f);
+const pxr::GfVec4f ColorDarkGrey        = pxr::GfVec4f(0.025f, 0.025f, 0.025f, 1.0f);
+const pxr::GfVec4f ColorDarkGreyNoAlpha = pxr::GfVec4f(0.025f, 0.025f, 0.025f, 0.0f);
+const pxr::GfVec4f ColorYellow          = pxr::GfVec4f(1.0f, 1.0f, 0.0f, 1.0f);
+const pxr::GfVec4f ColorWhite           = pxr::GfVec4f(1.0f, 1.0f, 1.0f, 1.0f);
 
 std::vector<char> readDataFile(const std::string& filename);
 

test/data/assets/usd/cube2.usda

@@ -0,0 +1,30 @@
+#usda 1.0
+(
+    defaultPrim = "World"
+    endTimeCode = 100
+    metersPerUnit = 0.01
+    startTimeCode = 0
+    timeCodesPerSecond = 24
+    upAxis = "Y"
+)
+
+def Xform "World"
+{
+    def Mesh "Cube"
+    {
+        int[] faceVertexCounts = [4, 4, 4, 4, 4, 4]
+        int[] faceVertexIndices = [0, 1, 3, 2, 0, 4, 5, 1, 1, 5, 6, 3, 2, 3, 6, 7, 0, 2, 7, 4, 4, 7, 6, 5]
+        normal3f[] normals = [(0, -1, 0), (0, -1, 0), (0, -1, 0), (0, -1, 0), (0, 0, -1), (0, 0, -1), (0, 0, -1), (0, 0, -1), (1, 0, 0), (1, 0, 0), (1, 0, 0), (1, 0, 0), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (-1, 0, 0), (-1, 0, 0), (-1, 0, 0), (-1, 0, 0), (0, 1, 0), (0, 1, 0), (0, 1, 0), (0, 1, 0)] (
+            interpolation = "faceVarying"
+        )
+        point3f[] points = [(-50, -50, -50), (50, -50, -50), (-50, -50, 50), (50, -50, 50), (-50, 50, -50), (50, 50, -50), (50, 50, 50), (-50, 50, 50)]
+        float2[] primvars:st = [(1, 0), (0, 0), (0, 1), (1, 1), (1, 0), (1, 1), (0, 1), (0, 0), (1, 0), (0, 0), (0, 1), (1, 1), (1, 0), (0, 0), (0, 1), (1, 1), (1, 0), (1, 1), (0, 1), (0, 0), (1, 0), (1, 1), (0, 1), (0, 0)] (
+            interpolation = "faceVarying"
+        )
+        uniform token subdivisionScheme = "none"
+        double3 xformOp:rotateXYZ = (40, 40, 0)
+        double3 xformOp:scale = (0.7, 0.7, 0.7)
+        double3 xformOp:translate = (0, 0, 0)
+        uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]
+    }
+}

test/tests/testMultiSampling.cpp

@@ -0,0 +1,311 @@
+// Copyright 2025 Autodesk, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifdef __APPLE__
+#include "TargetConditionals.h"
+#endif
+
+#include <RenderingFramework/TestContextCreator.h>
+#include <RenderingFramework/TestHelpers.h>
+
+#include <hvt/engine/viewportEngine.h>
+#include <hvt/sceneIndex/displayStyleOverrideSceneIndex.h>
+#include <hvt/sceneIndex/wireFrameSceneIndex.h>
+#include <hvt/tasks/resources.h>
+
+#include <pxr/base/plug/registry.h>
+
+#include <gtest/gtest.h>
+
+namespace
+{
+    // Arbitrary hard-coded path for the axis gizmo.
+    const pxr::SdfPath gizmosPath("/gizmos/axis");
+}
+
+TEST(howTo, validateMultiSampling2)
+{
+    // Helper to create the Hgi implementation.
+
+    auto context = TestHelpers::CreateTestContext();
+
+    TestHelpers::TestStage stage(context->_backend);
+
+    // Uses a specific model to better render the wire frame.
+    const auto sceneFilepath = TestHelpers::getAssetsDataFolder() / "usd" / "cube2.usda";
+    ASSERT_TRUE(stage.open(sceneFilepath.generic_u8string()));
+
+    struct FramePassInstances
+    {
+        hvt::RenderIndexProxyPtr renderIndex;
+        hvt::FramePassPtr sceneFramePass;
+    } mainFramePass, manipulatorFramePass;
+
+    // Defines the main frame pass i.e., the one containing the scene to display.
+
+    {
+        // Creates the render index by providing the hgi driver and the requested renderer name.
+
+        hvt::RendererDescriptor renderDesc;
+        renderDesc.hgiDriver    = &context->_backend->hgiDriver();
+        renderDesc.rendererName = "HdStormRendererPlugin";
+        hvt::ViewportEngine::CreateRenderer(mainFramePass.renderIndex, renderDesc);
+
+        // Creates the scene index containing the model displayed as wire frame.
+
+        pxr::HdSceneIndexBaseRefPtr sceneIndex =
+            hvt::ViewportEngine::CreateUSDSceneIndex(stage.stage());
+
+        sceneIndex = hvt::DisplayStyleOverrideSceneIndex::New(sceneIndex);
+        sceneIndex = hvt::WireFrameSceneIndex::New(sceneIndex);
+
+        mainFramePass.renderIndex->RenderIndex()->InsertSceneIndex(
+            sceneIndex, pxr::SdfPath::AbsoluteRootPath());
+
+        // Creates the frame pass instance.
+
+        hvt::FramePassDescriptor passDesc;
+        passDesc.renderIndex = mainFramePass.renderIndex->RenderIndex();
+        passDesc.uid         = pxr::SdfPath("/sceneFramePass");
+        mainFramePass.sceneFramePass =
+            hvt::ViewportEngine::CreateFramePass(passDesc);
+    }
+
+    // Defines a secondary frame pass containing a manipulator, but do not display it.
+
+    // Note: The test needs a second frame pass to test the reported issue but it only needs
+    // the first frame pass render.
+
+    {
+        // Creates the render index by providing the hgi driver and the requested renderer name.
+
+        hvt::RendererDescriptor renderDesc;
+        renderDesc.hgiDriver    = &context->_backend->hgiDriver();
+        renderDesc.rendererName = "HdStormRendererPlugin";
+        hvt::ViewportEngine::CreateRenderer(
+            manipulatorFramePass.renderIndex, renderDesc);
+
+        // Loads an arbitrary USD asset e.g., a manipulator in this case.
+
+        auto manipulatorStage = hvt::ViewportEngine::CreateStageFromFile(
+            hvt::GetGizmoPath("axisTripod.usda").generic_u8string());
+
+        // Creates the scene index containing the model.
+
+        pxr::HdSceneIndexBaseRefPtr sceneIndex =
+            hvt::ViewportEngine::CreateUSDSceneIndex(manipulatorStage);
+        manipulatorFramePass.renderIndex->RenderIndex()->InsertSceneIndex(sceneIndex, gizmosPath);
+
+        // Creates the frame pass instance.
+
+        hvt::FramePassDescriptor passDesc;
+        passDesc.renderIndex = manipulatorFramePass.renderIndex->RenderIndex();
+        passDesc.uid         = pxr::SdfPath("/sceneFramePass");
+        manipulatorFramePass.sceneFramePass =
+            hvt::ViewportEngine::CreateFramePass(passDesc);
+    }
+
+    // Renders 10 times (i.e., arbitrary number to guarantee best result).
+    int frameCount = 10;
+
+    auto render = [&]() {
+        // Updates the main frame pass.
+
+        {
+            auto& params = mainFramePass.sceneFramePass->params();
+
+            params.renderBufferSize = pxr::GfVec2i(context->width(), context->height());
+
+            params.viewInfo.viewport         = { { 0, 0 }, { context->width(), context->height() } };
+            params.viewInfo.viewMatrix       = stage.viewMatrix();
+            params.viewInfo.projectionMatrix = stage.projectionMatrix();
+            params.viewInfo.lights           = stage.defaultLights();
+            params.viewInfo.material         = stage.defaultMaterial();
+            params.viewInfo.ambient          = stage.defaultAmbient();
+
+            params.colorspace      = pxr::HdxColorCorrectionTokens->disabled;
+            params.backgroundColor = TestHelpers::ColorDarkGrey;
+            params.selectionColor  = TestHelpers::ColorYellow;
+
+            // Do not display right now, wait for the second frame pass.
+            params.enablePresentation = false;
+
+            // That's the default value, but enforce it to true in case...
+            params.enableMultisampling = true;
+
+            mainFramePass.sceneFramePass->Render();
+        }
+
+        // Gets the input AOV's from the first frame pass and use them in all overlays so the
+        // overlay's draw into the same color and depth buffers.
+
+        pxr::HdRenderBuffer* colorBuffer =
+            mainFramePass.sceneFramePass->GetRenderBuffer(pxr::HdAovTokens->color);
+
+        pxr::HdRenderBuffer* depthBuffer =
+            mainFramePass.sceneFramePass->GetRenderBuffer(pxr::HdAovTokens->depth);
+
+        const std::vector<std::pair<pxr::TfToken const&, pxr::HdRenderBuffer*>> inputAOVs = {
+            { pxr::HdAovTokens->color, colorBuffer }, { pxr::HdAovTokens->depth, depthBuffer }
+        };
+
+        // Updates the manipulator frame pass.
+
+        {
+
+            // Defines arbitrary dimensions for the manipulator.
+            const int width  = context->width() / 4;
+            const int height = context->height() / 4;
+
+            // Defines arbitrary positions for the manipulator.
+            const int posX = 10;
+            const int posY = 10;
+
+            auto& params = manipulatorFramePass.sceneFramePass->params();
+
+            params.renderBufferSize = pxr::GfVec2i(context->width(), context->height());
+
+            params.viewInfo.viewport         = { { posX, posY }, { width, height } };
+            params.viewInfo.viewMatrix       = stage.viewMatrix();
+            params.viewInfo.projectionMatrix = stage.projectionMatrix();
+            params.viewInfo.lights           = stage.defaultLights();
+            params.viewInfo.material         = stage.defaultMaterial();
+            params.viewInfo.ambient          = stage.defaultAmbient();
+
+            params.colorspace      = pxr::HdxColorCorrectionTokens->disabled;
+            params.backgroundColor = TestHelpers::ColorDarkGreyNoAlpha;
+            params.selectionColor  = TestHelpers::ColorYellow;
+
+            // Exclude the gizmo.
+            pxr::HdRprimCollection collection { hvt::FramePassParams().collection };
+            collection.SetExcludePaths({ gizmosPath });
+            params.collection = collection;
+
+            // Do not clear the background as it contains the previous frame pass result.
+            params.clearBackground = false;
+
+            // That's the default value, but enforce it to true in case...
+            params.enableMultisampling = true;
+
+            // Gets the list of tasks to render but use the render buffers from the main frame pass.
+            const pxr::HdTaskSharedPtrVector renderTasks =
+                manipulatorFramePass.sceneFramePass->GetRenderTasks(inputAOVs);
+
+            manipulatorFramePass.sceneFramePass->Render(renderTasks);
+        }
+
+        return --frameCount > 0;
+    };
+
+    // Runs the render loop (i.e., that's backend specific).
+
+    context->run(render, manipulatorFramePass.sceneFramePass.get());
+
+    // Validates the rendering result.
+
+    const std::string imageFile = std::string(test_info_->name());
+    ASSERT_TRUE(context->_backend->saveImage(imageFile));
+
+    ASSERT_TRUE(context->_backend->compareImages(imageFile));
+}
+
+TEST(howTo, validateMultiSampling1)
+{
+    // Helper to create the Hgi implementation.
+
+    auto context = TestHelpers::CreateTestContext();
+
+    TestHelpers::TestStage stage(context->_backend);
+
+    // Uses a specific model to better render the wire frame.
+    const auto sceneFilepath = TestHelpers::getAssetsDataFolder() / "usd" / "cube2.usda";
+    ASSERT_TRUE(stage.open(sceneFilepath.generic_u8string()));
+
+    struct FramePassInstances
+    {
+        hvt::RenderIndexProxyPtr renderIndex;
+        hvt::FramePassPtr sceneFramePass;
+    } mainFramePass;
+
+    // Defines the main frame pass i.e., the one containing the scene to display.
+
+    {
+        // Creates the render index by providing the hgi driver and the requested renderer name.
+
+        hvt::RendererDescriptor renderDesc;
+        renderDesc.hgiDriver    = &context->_backend->hgiDriver();
+        renderDesc.rendererName = "HdStormRendererPlugin";
+        hvt::ViewportEngine::CreateRenderer(mainFramePass.renderIndex, renderDesc);
+
+        // Creates the scene index containing the model displayed as a wire frame..
+
+        pxr::HdSceneIndexBaseRefPtr sceneIndex =
+            hvt::ViewportEngine::CreateUSDSceneIndex(stage.stage());
+
+        sceneIndex = hvt::DisplayStyleOverrideSceneIndex::New(sceneIndex);
+        sceneIndex = hvt::WireFrameSceneIndex::New(sceneIndex);
+
+        mainFramePass.renderIndex->RenderIndex()->InsertSceneIndex(
+            sceneIndex, pxr::SdfPath::AbsoluteRootPath());
+
+        // Creates the frame pass instance.
+
+        hvt::FramePassDescriptor passDesc;
+        passDesc.renderIndex = mainFramePass.renderIndex->RenderIndex();
+        passDesc.uid         = pxr::SdfPath("/sceneFramePass");
+        mainFramePass.sceneFramePass =
+            hvt::ViewportEngine::CreateFramePass(passDesc);
+    }
+
+    // Renders 10 times (i.e., arbitrary number to guarantee best result).
+    int frameCount = 10;
+
+    auto render = [&]() {
+        auto& params = mainFramePass.sceneFramePass->params();
+
+        params.renderBufferSize = pxr::GfVec2i(context->width(), context->height());
+
+        params.viewInfo.viewport         = { { 0, 0 }, { context->width(), context->height() } };
+        params.viewInfo.viewMatrix       = stage.viewMatrix();
+        params.viewInfo.projectionMatrix = stage.projectionMatrix();
+        params.viewInfo.lights           = stage.defaultLights();
+        params.viewInfo.material         = stage.defaultMaterial();
+        params.viewInfo.ambient          = stage.defaultAmbient();
+
+        params.colorspace      = pxr::HdxColorCorrectionTokens->disabled;
+        params.backgroundColor = TestHelpers::ColorDarkGrey;
+        params.selectionColor  = TestHelpers::ColorYellow;
+
+            // That's the default value, but enforce it to true in case...
+            params.enableMultisampling = true;
+
+        mainFramePass.sceneFramePass->Render();
+
+        return --frameCount > 0;
+    };
+
+    // Runs the render loop (i.e., that's backend specific).
+
+    context->run(render, mainFramePass.sceneFramePass.get());
+
+    // Validates the rendering result.
+
+    // Note: Compare the generated image with the baseline image from the previus unit test
+    // (i.e., the one with two frame passes) to trap the issue if any.
+
+    const std::string imageFile = std::string("validateMultiSampling2");
+    ASSERT_TRUE(context->_backend->saveImage(imageFile));
+
+    ASSERT_TRUE(context->_backend->compareImages(imageFile));
+}