Multiview support for vulkan

filament/backend/src/vulkan/VulkanContext.cpp

@@ -59,7 +59,11 @@ VkExtent2D VulkanAttachment::getExtent2D() const {
 
 VkImageView VulkanAttachment::getImageView() {
     assert_invariant(texture);
-    return texture->getAttachmentView(getSubresourceRange());
+    VkImageSubresourceRange range = getSubresourceRange();
+    if (range.layerCount > 1) {
+        return texture->getMultiviewAttachmentView(range);
+    }
+    return texture->getAttachmentView(range);
 }
 
 bool VulkanAttachment::isDepth() const {
@@ -73,7 +77,7 @@ VkImageSubresourceRange VulkanAttachment::getSubresourceRange() const {
             .baseMipLevel = uint32_t(level),
             .levelCount = 1,
             .baseArrayLayer = uint32_t(layer),
-            .layerCount = 1,
+            .layerCount = layerCount,
     };
 }
 

filament/backend/src/vulkan/VulkanContext.h

@@ -43,6 +43,8 @@ struct VulkanCommandBuffer;
 struct VulkanAttachment {
     VulkanTexture* texture = nullptr;
     uint8_t level = 0;
+    uint8_t baseViewIndex = 0;
+    uint8_t layerCount = 1;
     uint16_t layer = 0;
 
     bool isDepth() const;

filament/backend/src/vulkan/VulkanDriver.cpp

@@ -595,6 +595,8 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
             colorTargets[i] = {
                 .texture = mResourceAllocator.handle_cast<VulkanTexture*>(color[i].handle),
                 .level = color[i].level,
+                .baseViewIndex = color[i].baseViewIndex,
+                .layerCount = layerCount,
                 .layer = color[i].layer,
             };
             UTILS_UNUSED_IN_RELEASE VkExtent2D extent = colorTargets[i].getExtent2D();
@@ -609,6 +611,8 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
         depthStencil[0] = {
             .texture = mResourceAllocator.handle_cast<VulkanTexture*>(depth.handle),
             .level = depth.level,
+            .baseViewIndex = depth.baseViewIndex,
+            .layerCount = layerCount,
             .layer = depth.layer,
         };
         UTILS_UNUSED_IN_RELEASE VkExtent2D extent = depthStencil[0].getExtent2D();
@@ -621,6 +625,8 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
         depthStencil[1] = {
             .texture = mResourceAllocator.handle_cast<VulkanTexture*>(stencil.handle),
             .level = stencil.level,
+            .baseViewIndex = stencil.baseViewIndex,
+            .layerCount = layerCount,
             .layer = stencil.layer,
         };
         UTILS_UNUSED_IN_RELEASE VkExtent2D extent = depthStencil[1].getExtent2D();
@@ -637,7 +643,7 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
 
     auto renderTarget = mResourceAllocator.construct<VulkanRenderTarget>(rth, mPlatform->getDevice(),
             mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, width, height,
-            samples, colorTargets, depthStencil, mStagePool);
+            samples, colorTargets, depthStencil, mStagePool, layerCount);
     mResourceManager.acquire(renderTarget);
 }
 
@@ -1267,6 +1273,8 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
         }
     }
 
+    uint8_t renderTargetLayerCount = rt->getLayerCount();
+
     // Create the VkRenderPass or fetch it from cache.
     VulkanFboCache::RenderPassKey rpkey = {
         .initialColorLayoutMask = 0,
@@ -1277,10 +1285,14 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
         .discardEnd = discardEndVal,
         .samples = rt->getSamples(),
         .subpassMask = uint8_t(params.subpassMask),
+        .viewCount = renderTargetLayerCount,
     };
+
     for (int i = 0; i < MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT; i++) {
         const VulkanAttachment& info = rt->getColor(i);
+
         if (info.texture) {
+            assert_invariant(info.layerCount == renderTargetLayerCount);
             rpkey.initialColorLayoutMask |= 1 << i;
             rpkey.colorFormat[i] = info.getFormat();
             if (rpkey.samples > 1 && info.texture->samples == 1) {

filament/backend/src/vulkan/VulkanFboCache.cpp

@@ -43,6 +43,7 @@ bool VulkanFboCache::RenderPassEq::operator()(const RenderPassKey& k1,
     if (k1.samples != k2.samples) return false;
     if (k1.needsResolveMask != k2.needsResolveMask) return false;
     if (k1.subpassMask != k2.subpassMask) return false;
+    if (k1.viewCount != k2.viewCount) return false;
     return true;
 }
 
@@ -183,9 +184,28 @@ VkRenderPass VulkanFboCache::getRenderPass(RenderPassKey config) noexcept {
         .subpassCount = hasSubpasses ? 2u : 1u,
         .pSubpasses = subpasses,
         .dependencyCount = hasSubpasses ? 1u : 0u,
-        .pDependencies = dependencies
+        .pDependencies = dependencies,
     };
 
+    VkRenderPassMultiviewCreateInfo multiviewCreateInfo = {};
+    uint32_t subpassViewMask = (1 << config.viewCount) - 1;
+    // Prepare a view mask array for the maximum number of subpasses. All subpasses have all views
+    // activated.
+    uint32_t viewMasks[2] = {subpassViewMask, subpassViewMask};
+    if (config.viewCount > 1) {
+      // Fill the multiview create info.
+      multiviewCreateInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO;
+      multiviewCreateInfo.pNext = nullptr;
+      multiviewCreateInfo.subpassCount = hasSubpasses ? 2u : 1u;
+      multiviewCreateInfo.pViewMasks = viewMasks;
+      multiviewCreateInfo.dependencyCount = 0;
+      multiviewCreateInfo.pViewOffsets = nullptr;
+      multiviewCreateInfo.correlationMaskCount = 1;
+      multiviewCreateInfo.pCorrelationMasks = &subpassViewMask;
+
+      renderPassInfo.pNext = &multiviewCreateInfo;
+    }
+
     int attachmentIndex = 0;
 
     // Populate the Color Attachments.
@@ -288,16 +308,19 @@ VkRenderPass VulkanFboCache::getRenderPass(RenderPassKey config) noexcept {
         const bool clear = any(config.clear & TargetBufferFlags::DEPTH);
         const bool discardStart = any(config.discardStart & TargetBufferFlags::DEPTH);
         const bool discardEnd = any(config.discardEnd & TargetBufferFlags::DEPTH);
+        const VkAttachmentLoadOp loadOp = clear ? kClear : (discardStart ? kDontCare : kKeep);
         depthAttachmentRef.layout = imgutil::getVkLayout(VulkanLayout::DEPTH_ATTACHMENT);
         depthAttachmentRef.attachment = attachmentIndex;
+        VkImageLayout initialLayout = imgutil::getVkLayout(config.initialDepthLayout);
+
         attachments[attachmentIndex++] = {
             .format = config.depthFormat,
             .samples = (VkSampleCountFlagBits) config.samples,
-            .loadOp = clear ? kClear : (discardStart ? kDontCare : kKeep),
+            .loadOp = loadOp,
             .storeOp = discardEnd ? kDisableStore : kEnableStore,
             .stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE,
             .stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE,
-            .initialLayout = imgutil::getVkLayout(config.initialDepthLayout),
+            .initialLayout = initialLayout,
             .finalLayout = imgutil::getVkLayout(FINAL_DEPTH_ATTACHMENT_LAYOUT),
         };
     }

filament/backend/src/vulkan/VulkanFboCache.h

@@ -64,7 +64,7 @@ class VulkanFboCache {
         uint8_t samples; // 1 byte
         uint8_t needsResolveMask; // 1 byte
         uint8_t subpassMask; // 1 byte
-        uint8_t padding2; // 1 byte
+        uint8_t viewCount; // 1 byte
     };
     struct RenderPassVal {
         VkRenderPass handle;

filament/backend/src/vulkan/VulkanHandles.cpp

@@ -323,11 +323,12 @@ VulkanRenderTarget::VulkanRenderTarget(VkDevice device, VkPhysicalDevice physica
         VulkanContext const& context, VmaAllocator allocator, VulkanCommands* commands,
         uint32_t width, uint32_t height, uint8_t samples,
         VulkanAttachment color[MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT],
-        VulkanAttachment depthStencil[2], VulkanStagePool& stagePool)
+        VulkanAttachment depthStencil[2], VulkanStagePool& stagePool, uint8_t layerCount)
     : HwRenderTarget(width, height),
       VulkanResource(VulkanResourceType::RENDER_TARGET),
       mOffscreen(true),
-      mSamples(samples) {
+      mSamples(samples),
+      mLayerCount(layerCount) {
     for (int index = 0; index < MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT; index++) {
         mColor[index] = color[index];
     }

filament/backend/src/vulkan/VulkanHandles.h

@@ -304,7 +304,7 @@ struct VulkanRenderTarget : private HwRenderTarget, VulkanResource {
             VulkanContext const& context, VmaAllocator allocator,
             VulkanCommands* commands, uint32_t width, uint32_t height,
             uint8_t samples, VulkanAttachment color[MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT],
-            VulkanAttachment depthStencil[2], VulkanStagePool& stagePool);
+            VulkanAttachment depthStencil[2], VulkanStagePool& stagePool, uint8_t layerCount);
 
     // Creates a special "default" render target (i.e. associated with the swap chain)
     explicit VulkanRenderTarget();
@@ -319,6 +319,7 @@ struct VulkanRenderTarget : private HwRenderTarget, VulkanResource {
     VulkanAttachment& getMsaaDepth();
     uint8_t getColorTargetCount(const VulkanRenderPass& pass) const;
     uint8_t getSamples() const { return mSamples; }
+    uint8_t getLayerCount() { return mLayerCount; }
     bool hasDepth() const { return mDepth.texture; }
     bool isSwapChain() const { return !mOffscreen; }
     void bindToSwapChain(VulkanSwapChain& surf);
@@ -330,6 +331,7 @@ struct VulkanRenderTarget : private HwRenderTarget, VulkanResource {
     VulkanAttachment mMsaaDepthAttachment = {};
     const bool mOffscreen : 1;
     uint8_t mSamples : 7;
+    uint8_t mLayerCount = 1;
 };
 
 struct VulkanBufferObject;

filament/backend/src/vulkan/VulkanTexture.cpp

@@ -66,8 +66,8 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
       mStagePool(stagePool),
       mDevice(device),
       mAllocator(allocator),
-      mCommands(commands) {
-
+      mCommands(commands)
+      {
     // Create an appropriately-sized device-only VkImage, but do not fill it yet.
     VkImageCreateInfo imageInfo{.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,
             .imageType = target == SamplerType::SAMPLER_3D ? VK_IMAGE_TYPE_3D : VK_IMAGE_TYPE_2D,
@@ -387,12 +387,15 @@ void VulkanTexture::setPrimaryRange(uint32_t minMiplevel, uint32_t maxMiplevel)
 }
 
 VkImageView VulkanTexture::getAttachmentView(VkImageSubresourceRange range) {
-    // Attachments should only have one mipmap level and one layer.
     range.levelCount = 1;
     range.layerCount = 1;
     return getImageView(range, VK_IMAGE_VIEW_TYPE_2D, {});
 }
 
+VkImageView VulkanTexture::getMultiviewAttachmentView(VkImageSubresourceRange range) {
+    return getImageView(range, VK_IMAGE_VIEW_TYPE_2D_ARRAY, {});
+}
+
 VkImageView VulkanTexture::getViewForType(VkImageSubresourceRange const& range, VkImageViewType type) {
     return getImageView(range, type, mSwizzle);
 }

filament/backend/src/vulkan/VulkanTexture.h

@@ -73,6 +73,10 @@ struct VulkanTexture : public HwTexture, VulkanResource {
     // and the identity swizzle.
     VkImageView getAttachmentView(VkImageSubresourceRange range);
 
+    // Gets or creates a cached VkImageView for a single subresource that can be used as a render
+    // target attachment when rendering with multiview.
+    VkImageView getMultiviewAttachmentView(VkImageSubresourceRange range);
+
     // This is a workaround for the first few frames where we're waiting for the texture to actually
     // be uploaded.  In that case, we bind the sampler to an empty texture, but the corresponding
     // imageView needs to be of the right type. Hence, we provide an option to indicate the

filament/src/fg/FrameGraphRenderPass.h

@@ -48,7 +48,7 @@ struct FrameGraphRenderPass {
         Viewport viewport{};
         math::float4 clearColor{};
         uint8_t samples = 0;    // # of samples (0 = unset, default)
-        uint8_t layerCount = 0; // # of layer (# > 1 = multiview)
+        uint8_t layerCount = 1; // # of layer (# > 1 = multiview)
         backend::TargetBufferFlags clearFlags{};
         backend::TargetBufferFlags discardStart{};
     };