Vulkan: Support y-flip with no driver support.

include/platform/FeaturesVk.h

@@ -467,6 +467,10 @@ struct FeaturesVk : FeatureSetBase
         "emulateR32fImageAtomicExchange", FeatureCategory::VulkanWorkarounds,
         "Emulate r32f images with r32ui to support imageAtomicExchange.", &members,
         "http://anglebug.com/5535"};
+
+    Feature supportsNegativeViewport = {
+        "supportsNegativeViewport", FeatureCategory::VulkanFeatures,
+        "The driver supports inverting the viewport with a negative height.", &members};
 };
 
 inline FeaturesVk::FeaturesVk()  = default;

src/libANGLE/renderer/glslang_wrapper_utils.cpp

@@ -1807,12 +1807,28 @@ void SpirvTransformer::preRotateXY(spirv::IdRef xId,
     switch (mOptions.preRotation)
     {
         case SurfaceRotation::Identity:
-        case SurfaceRotation::FlippedIdentity:
             // [ 1  0]   [x]
             // [ 0  1] * [y]
             *rotatedXIdOut = xId;
             *rotatedYIdOut = yId;
             break;
+        case SurfaceRotation::FlippedIdentity:
+            if (mOptions.negativeViewportSupported)
+            {
+                // [ 1  0]   [x]
+                // [ 0  1] * [y]
+                *rotatedXIdOut = xId;
+                *rotatedYIdOut = yId;
+            }
+            else
+            {
+                // [ 1  0]   [x]
+                // [ 0 -1] * [y]
+                *rotatedXIdOut = xId;
+                *rotatedYIdOut = getNewId();
+                spirv::WriteFNegate(mSpirvBlobOut, mFloatId, *rotatedYIdOut, yId);
+            }
+            break;
         case SurfaceRotation::Rotated90Degrees:
         case SurfaceRotation::FlippedRotated90Degrees:
             // [ 0  1]   [x]

src/libANGLE/renderer/glslang_wrapper_utils.h

@@ -60,6 +60,7 @@ struct GlslangSpirvOptions
 {
     gl::ShaderType shaderType                 = gl::ShaderType::InvalidEnum;
     SurfaceRotation preRotation               = SurfaceRotation::Identity;
+    bool negativeViewportSupported            = false;
     bool transformPositionToVulkanClipSpace   = false;
     bool removeEarlyFragmentTestsOptimization = false;
     bool removeDebugInfo                      = false;

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -2634,8 +2634,7 @@ gl::Rectangle ContextVk::getCorrectedViewport(const gl::Rectangle &viewport) con
 void ContextVk::updateViewport(FramebufferVk *framebufferVk,
                                const gl::Rectangle &viewport,
                                float nearPlane,
-                               float farPlane,
-                               bool invertViewport)
+                               float farPlane)
 {
 
     gl::Box fbDimensions        = framebufferVk->getState().getDimensions();
@@ -2644,6 +2643,9 @@ void ContextVk::updateViewport(FramebufferVk *framebufferVk,
     RotateRectangle(getRotationDrawFramebuffer(), false, fbDimensions.width, fbDimensions.height,
                     correctedRect, &rotatedRect);
 
+    bool invertViewport =
+        isViewportFlipEnabledForDrawFBO() && getFeatures().supportsNegativeViewport.enabled;
+
     VkViewport vkViewport;
     gl_vk::GetViewport(
         rotatedRect, nearPlane, farPlane, invertViewport,
@@ -2801,7 +2803,7 @@ angle::Result ContextVk::syncState(const gl::Context *context,
             {
                 FramebufferVk *framebufferVk = vk::GetImpl(glState.getDrawFramebuffer());
                 updateViewport(framebufferVk, glState.getViewport(), glState.getNearPlane(),
-                               glState.getFarPlane(), isViewportFlipEnabledForDrawFBO());
+                               glState.getFarPlane());
                 // Update the scissor, which will be constrained to the viewport
                 updateScissor(glState);
                 break;
@@ -2984,7 +2986,7 @@ angle::Result ContextVk::syncState(const gl::Context *context,
                 SpecConstUsageBits usageBits = getCurrentProgramSpecConstUsageBits();
                 updateGraphicsPipelineDescWithSpecConstUsageBits(usageBits);
                 updateViewport(mDrawFramebuffer, glState.getViewport(), glState.getNearPlane(),
-                               glState.getFarPlane(), isViewportFlipEnabledForDrawFBO());
+                               glState.getFarPlane());
                 updateColorMasks(glState.getBlendStateExt());
                 updateRasterizationSamples(mDrawFramebuffer->getSamples());
 
@@ -3097,8 +3099,7 @@ angle::Result ContextVk::syncState(const gl::Context *context,
                         case gl::State::ExtendedDirtyBitType::EXTENDED_DIRTY_BIT_CLIP_CONTROL:
                             updateViewport(vk::GetImpl(glState.getDrawFramebuffer()),
                                            glState.getViewport(), glState.getNearPlane(),
-                                           glState.getFarPlane(),
-                                           isViewportFlipEnabledForDrawFBO());
+                                           glState.getFarPlane());
                             // Since we are flipping the y coordinate, update front face state
                             mGraphicsPipelineDesc->updateFrontFace(&mGraphicsPipelineTransition,
                                                                    glState.getRasterizerState(),
@@ -3258,7 +3259,8 @@ void ContextVk::updateGraphicsPipelineDescWithSpecConstUsageBits(SpecConstUsageB
     SurfaceRotation rotationAndFlip = mCurrentRotationDrawFramebuffer;
     ASSERT(ToUnderlying(rotationAndFlip) < ToUnderlying(SurfaceRotation::FlippedIdentity));
     bool yFlipped =
-        isViewportFlipEnabledForDrawFBO() && usageBits.test(sh::vk::SpecConstUsage::YFlip);
+        isViewportFlipEnabledForDrawFBO() && (usageBits.test(sh::vk::SpecConstUsage::YFlip) ||
+                                              !getFeatures().supportsNegativeViewport.enabled);
 
     // usageBits are only set when specialization constants are used.  With gl_Position pre-rotation
     // handled by the SPIR-V transformer, we need to have this information even when the driver

src/libANGLE/renderer/vulkan/ContextVk.h

@@ -737,8 +737,7 @@ class ContextVk : public ContextImpl, public vk::Context, public MultisampleText
     void updateViewport(FramebufferVk *framebufferVk,
                         const gl::Rectangle &viewport,
                         float nearPlane,
-                        float farPlane,
-                        bool invertViewport);
+                        float farPlane);
     void updateDepthRange(float nearPlane, float farPlane);
     void updateFlipViewportDrawFramebuffer(const gl::State &glState);
     void updateFlipViewportReadFramebuffer(const gl::State &glState);

src/libANGLE/renderer/vulkan/ProgramExecutableVk.cpp

@@ -33,8 +33,10 @@ bool ValidateTransformedSpirV(ContextVk *contextVk,
     for (gl::ShaderType shaderType : linkedShaderStages)
     {
         GlslangSpirvOptions options;
-        options.shaderType                         = shaderType;
-        options.preRotation                        = SurfaceRotation::FlippedRotated90Degrees;
+        options.shaderType  = shaderType;
+        options.preRotation = SurfaceRotation::FlippedRotated90Degrees;
+        options.negativeViewportSupported =
+            contextVk->getFeatures().supportsNegativeViewport.enabled;
         options.transformPositionToVulkanClipSpace = true;
         options.removeDebugInfo                    = true;
         options.isTransformFeedbackStage           = shaderType == lastPreFragmentStage;
@@ -135,8 +137,9 @@ angle::Result ProgramInfo::initProgram(ContextVk *contextVk,
     options.shaderType = shaderType;
     options.removeEarlyFragmentTestsOptimization =
         shaderType == gl::ShaderType::Fragment && optionBits.removeEarlyFragmentTestsOptimization;
-    options.removeDebugInfo          = !contextVk->getRenderer()->getEnableValidationLayers();
-    options.isTransformFeedbackStage = isLastPreFragmentStage;
+    options.removeDebugInfo           = !contextVk->getRenderer()->getEnableValidationLayers();
+    options.isTransformFeedbackStage  = isLastPreFragmentStage;
+    options.negativeViewportSupported = contextVk->getFeatures().supportsNegativeViewport.enabled;
 
     if (isLastPreFragmentStage)
     {

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -2010,6 +2010,10 @@ void RendererVk::initFeatures(DisplayVk *displayVk,
     bool isSwiftShader =
         IsSwiftshader(mPhysicalDeviceProperties.vendorID, mPhysicalDeviceProperties.deviceID);
 
+    bool supportsNegativeViewport =
+        ExtensionFound(VK_KHR_MAINTENANCE1_EXTENSION_NAME, deviceExtensionNames) ||
+        mPhysicalDeviceProperties.apiVersion >= VK_API_VERSION_1_1;
+
     if (mLineRasterizationFeatures.bresenhamLines == VK_TRUE)
     {
         ASSERT(mLineRasterizationFeatures.sType ==
@@ -2196,7 +2200,8 @@ void RendererVk::initFeatures(DisplayVk *displayVk,
         ExtensionFound(VK_EXT_EXTERNAL_MEMORY_HOST_EXTENSION_NAME, deviceExtensionNames));
 
     // Android pre-rotation support can be disabled.
-    ANGLE_FEATURE_CONDITION(&mFeatures, enablePreRotateSurfaces, IsAndroid());
+    ANGLE_FEATURE_CONDITION(&mFeatures, enablePreRotateSurfaces,
+                            IsAndroid() && supportsNegativeViewport);
 
     // Currently disabled by default: http://anglebug.com/3078
     ANGLE_FEATURE_CONDITION(
@@ -2278,6 +2283,9 @@ void RendererVk::initFeatures(DisplayVk *displayVk,
     // required.
     ANGLE_FEATURE_CONDITION(&mFeatures, emulateR32fImageAtomicExchange, true);
 
+    // Negative viewports are exposed in the Maintenance1 extension and in core Vulkan 1.1+.
+    ANGLE_FEATURE_CONDITION(&mFeatures, supportsNegativeViewport, supportsNegativeViewport);
+
     angle::PlatformMethods *platform = ANGLEPlatformCurrent();
     platform->overrideFeaturesVk(platform, &mFeatures);
 

src/tests/gl_tests/SimpleOperationTest.cpp

@@ -1212,13 +1212,15 @@ ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND(
     WithMetalForcedBufferGPUStorage(ES3_METAL()),
     WithMetalMemoryBarrierAndCheapRenderPass(ES3_METAL(),
                                              /* hasBarrier */ false,
-                                             /* cheapRenderPass */ false));
+                                             /* cheapRenderPass */ false),
+    WithNoVulkanViewportFlip(ES2_VULKAN()));
 
 ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND(
     TriangleFanDrawTest,
     WithMetalForcedBufferGPUStorage(ES3_METAL()),
     WithMetalMemoryBarrierAndCheapRenderPass(ES3_METAL(),
                                              /* hasBarrier */ false,
-                                             /* cheapRenderPass */ false));
+                                             /* cheapRenderPass */ false),
+    WithNoVulkanViewportFlip(ES2_VULKAN()));
 
 }  // namespace

src/tests/test_utils/angle_test_configs.cpp

@@ -254,6 +254,15 @@ std::ostream &operator<<(std::ostream &stream, const PlatformParameters &pp)
         stream << "_ForceMetalBufferGPUStorage";
     }
 
+    if (pp.eglParameters.supportsVulkanViewportFlip == EGL_TRUE)
+    {
+        stream << "_VulkanViewportFlip";
+    }
+    else if (pp.eglParameters.supportsVulkanViewportFlip == EGL_FALSE)
+    {
+        stream << "_NoVulkanViewportFlip";
+    }
+
     return stream;
 }
 

src/tests/test_utils/angle_test_configs.h

@@ -281,6 +281,13 @@ inline PlatformParameters WithAsyncCommandQueueFeatureVulkan(const PlatformParam
     withAsyncCommandQueue.eglParameters.asyncCommandQueueFeatureVulkan = EGL_TRUE;
     return withAsyncCommandQueue;
 }
+
+inline PlatformParameters WithNoVulkanViewportFlip(const PlatformParameters &params)
+{
+    PlatformParameters withoutVulkanViewportFlip                       = params;
+    withoutVulkanViewportFlip.eglParameters.supportsVulkanViewportFlip = EGL_FALSE;
+    return withoutVulkanViewportFlip;
+}
 }  // namespace angle
 
 #endif  // ANGLE_TEST_CONFIGS_H_

src/tests/test_utils/angle_test_instantiate.cpp

@@ -564,6 +564,7 @@ bool IsConfigAllowlisted(const SystemInfo &systemInfo, const PlatformParameters
         switch (param.getRenderer())
         {
             case EGL_PLATFORM_ANGLE_TYPE_OPENGLES_ANGLE:
+                return true;
             case EGL_PLATFORM_ANGLE_TYPE_VULKAN_ANGLE:
                 // Swiftshader's vulkan frontend doesn't build on Android.
                 if (param.getDeviceType() == EGL_PLATFORM_ANGLE_DEVICE_TYPE_SWIFTSHADER_ANGLE)
@@ -574,6 +575,10 @@ bool IsConfigAllowlisted(const SystemInfo &systemInfo, const PlatformParameters
                 {
                     return false;
                 }
+                if (param.eglParameters.supportsVulkanViewportFlip == EGL_FALSE)
+                {
+                    return false;
+                }
                 return true;
             default:
                 return false;

util/EGLPlatformParameters.h

@@ -64,7 +64,7 @@ struct EGLPlatformParameters
                         shaderStencilOutputFeature, genMultipleMipsPerPassFeature, platformMethods,
                         robustness, emulatedPrerotation, asyncCommandQueueFeatureVulkan,
                         hasExplicitMemBarrierFeatureMtl, hasCheapRenderPassFeatureMtl,
-                        forceBufferGPUStorageFeatureMtl);
+                        forceBufferGPUStorageFeatureMtl, supportsVulkanViewportFlip);
     }
 
     EGLint renderer                               = EGL_PLATFORM_ANGLE_TYPE_DEFAULT_ANGLE;
@@ -85,6 +85,7 @@ struct EGLPlatformParameters
     EGLint hasExplicitMemBarrierFeatureMtl        = EGL_DONT_CARE;
     EGLint hasCheapRenderPassFeatureMtl           = EGL_DONT_CARE;
     EGLint forceBufferGPUStorageFeatureMtl        = EGL_DONT_CARE;
+    EGLint supportsVulkanViewportFlip             = EGL_DONT_CARE;
     angle::PlatformMethods *platformMethods       = nullptr;
 };
 

util/EGLWindow.cpp

@@ -206,6 +206,15 @@ bool EGLWindow::initializeDisplay(OSWindow *osWindow,
         disabledFeatureOverrides.push_back("gen_multiple_mips_per_pass");
     }
 
+    if (params.supportsVulkanViewportFlip == EGL_TRUE)
+    {
+        enabledFeatureOverrides.push_back("supportsViewportFlip");
+    }
+    else if (params.supportsVulkanViewportFlip == EGL_FALSE)
+    {
+        disabledFeatureOverrides.push_back("supportsViewportFlip");
+    }
+
     switch (params.emulatedPrerotation)
     {
         case 90: