Adds multiview to CubeXr

include/ppx/application.h

@@ -89,6 +89,7 @@ struct StandardOptions
 #if defined(PPX_BUILD_XR)
     std::shared_ptr<KnobFlag<std::pair<int, int>>>      pXrUiResolution;
     std::shared_ptr<KnobFlag<std::vector<std::string>>> pXrRequiredExtensions;
+    std::shared_ptr<KnobFlag<bool>>                     pXrEnableMultiview;
 #endif
 
     std::shared_ptr<KnobFlag<std::vector<std::string>>> pAssetsPaths;
@@ -119,11 +120,6 @@ struct ApplicationSettings
     {
         bool enable = false;
 
-        // Multiview will create one swapchain with layers per view
-        // One Application::Render then should use multiview shaders
-        // to render to both layers, as opposed to non multiview
-        // where there is one swapchain per view, each with a ::Render
-        bool enableMultiView = false;
         // Whether to create depth swapchains in addition to color swapchains,
         // and submit the depth info to the runtime as an additional layer.
         bool     enableDepthSwapchain = false;
@@ -211,6 +207,7 @@ struct ApplicationSettings
 #if defined(PPX_BUILD_XR)
         std::pair<int, int>      xrUiResolution       = std::make_pair(0, 0);
         std::vector<std::string> xrRequiredExtensions = {};
+        bool                     xrEnableMultiview    = false;
 #endif
     } standardKnobsDefaultValue;
 };

projects/cube_xr/CMakeLists.txt

@@ -19,4 +19,4 @@ add_samples_for_all_apis(
     "CubeXr.h"
     "CubeXr.cpp"
     "main.cpp"
-    SHADER_DEPENDENCIES "shader_vertex_colors")
+    SHADER_DEPENDENCIES "shader_vertex_colors_multi")

projects/cube_xr/CubeXr.cpp

@@ -38,7 +38,7 @@ void CubeXrApp::Setup()
     // Uniform buffer
     {
         grfx::BufferCreateInfo bufferCreateInfo        = {};
-        bufferCreateInfo.size                          = PPX_MINIMUM_UNIFORM_BUFFER_SIZE;
+        bufferCreateInfo.size                          = std::max(sizeof(UniformBufferData), (uint64_t)PPX_MINIMUM_UNIFORM_BUFFER_SIZE);
         bufferCreateInfo.usageFlags.bits.uniformBuffer = true;
         bufferCreateInfo.memoryUsage                   = grfx::MEMORY_USAGE_CPU_TO_GPU;
 
@@ -68,12 +68,12 @@ void CubeXrApp::Setup()
 
     // Pipeline
     {
-        std::vector<char> bytecode = LoadShader("basic/shaders", "VertexColors.vs");
+        std::vector<char> bytecode = LoadShader("basic/shaders", "VertexColorsMulti.vs");
         PPX_ASSERT_MSG(!bytecode.empty(), "VS shader bytecode load failed");
         grfx::ShaderModuleCreateInfo shaderCreateInfo = {static_cast<uint32_t>(bytecode.size()), bytecode.data()};
         PPX_CHECKED_CALL(GetDevice()->CreateShaderModule(&shaderCreateInfo, &mVS));
 
-        bytecode = LoadShader("basic/shaders", "VertexColors.ps");
+        bytecode = LoadShader("basic/shaders", "VertexColorsMulti.ps");
         PPX_ASSERT_MSG(!bytecode.empty(), "PS shader bytecode load failed");
         shaderCreateInfo = {static_cast<uint32_t>(bytecode.size()), bytecode.data()};
         PPX_CHECKED_CALL(GetDevice()->CreateShaderModule(&shaderCreateInfo, &mPS));
@@ -103,6 +103,8 @@ void CubeXrApp::Setup()
         gpCreateInfo.outputState.renderTargetFormats[0] = GetSwapchain()->GetColorFormat();
         gpCreateInfo.outputState.depthStencilFormat     = GetSwapchain()->GetDepthFormat();
         gpCreateInfo.pPipelineInterface                 = mPipelineInterface;
+        gpCreateInfo.multiViewState.viewMask            = GetXrComponent().GetDefaultViewMask();
+        gpCreateInfo.multiViewState.correlationMask     = GetXrComponent().GetDefaultViewMask();
         PPX_CHECKED_CALL(GetDevice()->CreateGraphicsPipeline(&gpCreateInfo, &mPipeline));
     }
 
@@ -201,11 +203,13 @@ void CubeXrApp::Setup()
 
 void CubeXrApp::Render()
 {
-    PerFrame& frame            = mPerFrame[0];
-    uint32_t  imageIndex       = UINT32_MAX;
-    uint32_t  currentViewIndex = 0;
+    PerFrame&    frame            = mPerFrame[0];
+    uint32_t     imageIndex       = UINT32_MAX;
+    uint32_t     currentViewIndex = 0;
+    XrComponent& xrComponent      = GetXrComponent();
+
     if (IsXrEnabled()) {
-        currentViewIndex = GetXrComponent().GetCurrentViewIndex();
+        currentViewIndex = xrComponent.GetCurrentViewIndex();
     }
 
     // Render UI into a different composition layer.
@@ -269,20 +273,32 @@ void CubeXrApp::Render()
     // Update uniform buffer.
     {
         float    t = GetElapsedSeconds();
-        float4x4 P = glm::perspective(glm::radians(60.0f), GetWindowAspect(), 0.001f, 10000.0f);
-        float4x4 V = glm::lookAt(float3(0, 0, 0), float3(0, 0, 1), float3(0, 1, 0));
+        float4x4 M = glm::translate(float3(0, 0, -3)) * glm::rotate(t, float3(0, 0, 1)) * glm::rotate(t, float3(0, 1, 0)) * glm::rotate(t, float3(1, 0, 0));
 
         if (IsXrEnabled()) {
-            const Camera& camera = GetXrComponent().GetCamera();
-            P                    = camera.GetProjectionMatrix();
-            V                    = camera.GetViewMatrix();
+            xrComponent.SetCurrentViewIndex(0);
+            frame.uniform_buffer_data.M[0] = xrComponent.GetCamera().GetViewProjectionMatrix() * M;
+
+            xrComponent.SetCurrentViewIndex(1);
+            frame.uniform_buffer_data.M[1] = xrComponent.GetCamera().GetViewProjectionMatrix() * M;
+        }
+        else {
+            const Camera& camera           = xrComponent.GetCamera();
+            float4x4      P                = camera.GetProjectionMatrix();
+            float4x4      V                = camera.GetViewMatrix();
+            frame.uniform_buffer_data.M[0] = frame.uniform_buffer_data.M[1] = P * V * M;
+        }
+
+        // If multiview is active, we have one render pass with Left/Right poses loaded.
+        // If not multiview, this entire render call will happen again, and we switch to current view index.
+
+        if (!xrComponent.IsMultiView()) {
+            frame.uniform_buffer_data.M[0] = frame.uniform_buffer_data.M[IsXrEnabled() ? xrComponent.GetCurrentViewIndex() : 0];
         }
-        float4x4 M   = glm::translate(float3(0, 0, -3)) * glm::rotate(t, float3(0, 0, 1)) * glm::rotate(t, float3(0, 1, 0)) * glm::rotate(t, float3(1, 0, 0));
-        float4x4 mat = P * V * M;
 
         void* pData = nullptr;
         PPX_CHECKED_CALL(mUniformBuffer->MapMemory(0, &pData));
-        memcpy(pData, &mat, sizeof(mat));
+        memcpy(pData, &frame.uniform_buffer_data, sizeof(frame.uniform_buffer_data));
         mUniformBuffer->UnmapMemory();
     }
 

projects/cube_xr/CubeXr.h

@@ -28,6 +28,13 @@ class CubeXrApp
     virtual void Render() override;
 
 private:
+    struct UniformBufferData
+    {
+        // Pose of each Cube
+        // One for each eye, but second only used in multi-view
+        ppx::float4x4 M[2];
+    };
+
     struct PerFrame
     {
         grfx::CommandBufferPtr cmd;
@@ -36,6 +43,8 @@ class CubeXrApp
         grfx::SemaphorePtr     renderCompleteSemaphore;
         grfx::FencePtr         renderCompleteFence;
 
+        UniformBufferData uniform_buffer_data = {};
+
         // XR UI per frame elements.
         grfx::CommandBufferPtr uiCmd;
         grfx::FencePtr         uiRenderCompleteFence;

src/ppx/application.cpp

@@ -162,7 +162,7 @@ Result Application::InitializeGrfxDevice()
         ci.pVulkanDeviceFeatures  = nullptr;
         ci.supportShadingRateMode = mSettings.grfx.device.supportShadingRateMode;
 #if defined(PPX_BUILD_XR)
-        ci.multiView    = IsXrEnabled() && mSettings.xr.enableMultiView;
+        ci.multiView    = IsXrEnabled() && mStandardOpts.pXrEnableMultiview->GetValue();
         ci.pXrComponent = IsXrEnabled() ? &mXrComponent : nullptr;
 #endif
 
@@ -682,6 +682,10 @@ void Application::InitStandardKnobs()
         "to the base extensions. Any required extensions that are not supported by the "
         "target system will cause the application to immediately exit.");
     mStandardOpts.pXrRequiredExtensions->SetFlagParameters("<extension>");
+
+    GetKnobManager().InitKnob(&mStandardOpts.pXrEnableMultiview, "xr-enable-multiview", mSettings.standardKnobsDefaultValue.xrEnableMultiview);
+    mStandardOpts.pXrEnableMultiview->SetFlagDescription(
+        "Specify whether or not multiview should be enabled for the application.");
 #endif
 
     GetKnobManager().InitKnob(&mStandardOpts.pShadingRateMode, "shading-rate-mode", "");
@@ -973,7 +977,7 @@ void Application::InitializeXRComponentBeforeGrfxDeviceInit()
         createInfo.enableDebug          = mSettings.grfx.enableDebug;
         createInfo.enableQuadLayer      = mSettings.enableImGui;
         createInfo.enableDepthSwapchain = mSettings.xr.enableDepthSwapchain;
-        createInfo.enableMultiView      = mSettings.xr.enableMultiView;
+        createInfo.enableMultiView      = mStandardOpts.pXrEnableMultiview->GetValue();
         const auto resolution           = mStandardOpts.pResolution->GetValue();
         const bool hasResolutionFlag    = (resolution.first > 0 && resolution.second > 0);
         if (hasResolutionFlag) {