Vulkan: EXT_multisampled_render_to_texture2 support

src/libANGLE/Framebuffer.cpp

@@ -1576,37 +1576,34 @@ angle::Result Framebuffer::blit(const Context *context,
 
 int Framebuffer::getSamples(const Context *context) const
 {
-    return (isComplete(context) ? getCachedSamples(context, AttachmentSampleType::Emulated) : 0);
-}
-
-int Framebuffer::getResourceSamples(const Context *context) const
-{
-    return (isComplete(context) ? getCachedSamples(context, AttachmentSampleType::Resource) : 0);
-}
+    if (!isComplete(context))
+    {
+        return 0;
+    }
 
-int Framebuffer::getCachedSamples(const Context *context, AttachmentSampleType sampleType) const
-{
     ASSERT(mCachedStatus.valid() && mCachedStatus.value() == GL_FRAMEBUFFER_COMPLETE);
 
     // For a complete framebuffer, all attachments must have the same sample count.
     // In this case return the first nonzero sample size.
-    const auto *firstNonNullAttachment = mState.getFirstNonNullAttachment();
-    if (firstNonNullAttachment)
+    const FramebufferAttachment *firstNonNullAttachment = mState.getFirstNonNullAttachment();
+    ASSERT(firstNonNullAttachment == nullptr || firstNonNullAttachment->isAttached());
+
+    return firstNonNullAttachment ? firstNonNullAttachment->getSamples() : 0;
+}
+
+int Framebuffer::getReadBufferResourceSamples(const Context *context) const
+{
+    if (!isComplete(context))
     {
-        ASSERT(firstNonNullAttachment->isAttached());
-        if (sampleType == AttachmentSampleType::Resource)
-        {
-            return firstNonNullAttachment->getResourceSamples();
-        }
-        else
-        {
-            ASSERT(sampleType == AttachmentSampleType::Emulated);
-            return firstNonNullAttachment->getSamples();
-        }
+        return 0;
     }
 
-    // No attachments found.
-    return 0;
+    ASSERT(mCachedStatus.valid() && mCachedStatus.value() == GL_FRAMEBUFFER_COMPLETE);
+
+    const FramebufferAttachment *readAttachment = mState.getReadAttachment();
+    ASSERT(readAttachment == nullptr || readAttachment->isAttached());
+
+    return readAttachment ? readAttachment->getResourceSamples() : 0;
 }
 
 angle::Result Framebuffer::getSamplePosition(const Context *context,

src/libANGLE/Framebuffer.h

@@ -49,15 +49,6 @@ class State;
 class Texture;
 class TextureCapsMap;
 
-enum class AttachmentSampleType
-{
-    // The sample count of the actual resource
-    Resource,
-    // If render_to_texture is used, this is the sample count of the multisampled
-    // texture that is created behind the scenes.
-    Emulated
-};
-
 class FramebufferState final : angle::NonCopyable
 {
   public:
@@ -278,7 +269,7 @@ class Framebuffer final : public angle::ObserverInterface,
 
     // This method calls checkStatus.
     int getSamples(const Context *context) const;
-    int getResourceSamples(const Context *context) const;
+    int getReadBufferResourceSamples(const Context *context) const;
 
     angle::Result getSamplePosition(const Context *context, size_t index, GLfloat *xy) const;
 
@@ -309,9 +300,6 @@ class Framebuffer final : public angle::ObserverInterface,
         return checkStatusImpl(context);
     }
 
-    // For when we don't want to check completeness in getSamples().
-    int getCachedSamples(const Context *context, AttachmentSampleType sampleType) const;
-
     // Helper for checkStatus == GL_FRAMEBUFFER_COMPLETE.
     ANGLE_INLINE bool isComplete(const Context *context) const
     {

src/libANGLE/renderer/vulkan/FramebufferVk.cpp

@@ -2142,7 +2142,13 @@ angle::Result FramebufferVk::startNewRenderPass(ContextVk *contextVk,
         VkAttachmentStoreOp depthStoreOp   = VK_ATTACHMENT_STORE_OP_STORE;
         VkAttachmentStoreOp stencilStoreOp = VK_ATTACHMENT_STORE_OP_STORE;
 
-        if (!depthStencilRenderTarget->hasDefinedContent())
+        // If the image data was previously discarded (with no update in between), don't attempt to
+        // load the image.  Additionally, if the multisampled image data is transient and there is
+        // no resolve attachment, there's no data to load.  The latter is the case with
+        // depth/stencil texture attachments per GL_EXT_multisampled_render_to_texture2.
+        if (!depthStencilRenderTarget->hasDefinedContent() ||
+            (depthStencilRenderTarget->isImageTransient() &&
+             !depthStencilRenderTarget->hasResolveAttachment()))
         {
             depthLoadOp   = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
             stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;

src/libANGLE/renderer/vulkan/vk_caps_utils.cpp

@@ -76,18 +76,19 @@ void RendererVk::ensureCapsInitialized() const
 
     // Enable this for simple buffer readback testing, but some functionality is missing.
     // TODO(jmadill): Support full mapBufferRange extension.
-    mNativeExtensions.mapBufferOES                = true;
-    mNativeExtensions.mapBufferRange              = true;
-    mNativeExtensions.textureStorage              = true;
-    mNativeExtensions.drawBuffers                 = true;
-    mNativeExtensions.fragDepth                   = true;
-    mNativeExtensions.framebufferBlit             = true;
-    mNativeExtensions.framebufferMultisample      = true;
-    mNativeExtensions.multisampledRenderToTexture = true;
-    mNativeExtensions.copyTexture                 = true;
-    mNativeExtensions.copyTexture3d               = true;
-    mNativeExtensions.copyCompressedTexture       = true;
-    mNativeExtensions.debugMarker                 = true;
+    mNativeExtensions.mapBufferOES                 = true;
+    mNativeExtensions.mapBufferRange               = true;
+    mNativeExtensions.textureStorage               = true;
+    mNativeExtensions.drawBuffers                  = true;
+    mNativeExtensions.fragDepth                    = true;
+    mNativeExtensions.framebufferBlit              = true;
+    mNativeExtensions.framebufferMultisample       = true;
+    mNativeExtensions.multisampledRenderToTexture  = true;
+    mNativeExtensions.multisampledRenderToTexture2 = true;
+    mNativeExtensions.copyTexture                  = true;
+    mNativeExtensions.copyTexture3d                = true;
+    mNativeExtensions.copyCompressedTexture        = true;
+    mNativeExtensions.debugMarker                  = true;
     mNativeExtensions.robustness =
         !IsSwiftshader(mPhysicalDeviceProperties.vendorID, mPhysicalDeviceProperties.deviceID) &&
         !IsARM(mPhysicalDeviceProperties.vendorID);

src/libANGLE/validationES.cpp

@@ -1414,7 +1414,7 @@ bool ValidateBlitFramebufferParameters(const Context *context,
     }
 
     // Not allow blitting to MS buffers, therefore if renderToTextureSamples exist,
-    // consider it MS. needResourceSamples = false
+    // consider it MS. checkReadBufferResourceSamples = false
     if (!ValidateFramebufferNotMultisampled(context, drawFramebuffer, false))
     {
         return false;
@@ -2596,8 +2596,8 @@ bool ValidateCopyTexImageParametersBase(const Context *context,
         return false;
     }
 
-    // needResourceSamples = true. Treat renderToTexture textures as single sample since they will
-    // be resolved before copying
+    // checkReadBufferResourceSamples = true. Treat renderToTexture textures as single sample since
+    // they will be resolved before copying.
     if (!readFramebuffer->isDefault() &&
         !ValidateFramebufferNotMultisampled(context, readFramebuffer, true))
     {
@@ -6632,10 +6632,11 @@ bool ValidateGetInternalFormativBase(const Context *context,
 
 bool ValidateFramebufferNotMultisampled(const Context *context,
                                         const Framebuffer *framebuffer,
-                                        bool needResourceSamples)
+                                        bool checkReadBufferResourceSamples)
 {
-    int samples = needResourceSamples ? framebuffer->getResourceSamples(context)
-                                      : framebuffer->getSamples(context);
+    int samples = checkReadBufferResourceSamples
+                      ? framebuffer->getReadBufferResourceSamples(context)
+                      : framebuffer->getSamples(context);
     if (samples != 0)
     {
         context->validationError(GL_INVALID_OPERATION, kInvalidMultisampledFramebufferOperation);

src/libANGLE/validationES.h

@@ -650,7 +650,7 @@ bool ValidateGetInternalFormativBase(const Context *context,
 
 bool ValidateFramebufferNotMultisampled(const Context *context,
                                         const Framebuffer *framebuffer,
-                                        bool needResourceSamples);
+                                        bool checkReadBufferResourceSamples);
 
 bool ValidateMultitextureUnit(const Context *context, GLenum texture);
 

src/libANGLE/validationES2.cpp

@@ -6713,7 +6713,9 @@ bool ValidateFramebufferTexture2DMultisampleEXT(const Context *context,
         return false;
     }
 
-    if (attachment != GL_COLOR_ATTACHMENT0)
+    // Unless EXT_multisampled_render_to_texture2 is enabled, only color attachment 0 can be used.
+    if (!context->getExtensions().multisampledRenderToTexture2 &&
+        attachment != GL_COLOR_ATTACHMENT0)
     {
         context->validationError(GL_INVALID_ENUM, kInvalidAttachment);
         return false;