Implement multisample "disable" in Vulkan

Emulates multisample disable by colocating all samples at pixel
center. Multisample disable will be required in order for us to
integrate mixed samples.

Change-Id: I52b67e22c979584b5d001e737a08eef07bd7ffe2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/253282
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>

src/gpu/GrPipeline.cpp

@@ -99,7 +99,15 @@ GrPipeline::GrPipeline(GrScissorTest scissorTest, sk_sp<const GrXferProcessor> x
     }
 }
 
-uint32_t GrPipeline::getBlendInfoKey() const {
+void GrPipeline::genKey(GrProcessorKeyBuilder* b, const GrCaps& caps) const {
+    // kSnapVerticesToPixelCenters is implemented in a shader.
+    InputFlags ignoredFlags = InputFlags::kSnapVerticesToPixelCenters;
+    if (!caps.multisampleDisableSupport()) {
+        // Ganesh will omit kHWAntialias regardless multisampleDisableSupport.
+        ignoredFlags |= InputFlags::kHWAntialias;
+    }
+    b->add32((uint32_t)fFlags & ~(uint32_t)ignoredFlags);
+
     const GrXferProcessor::BlendInfo& blendInfo = this->getXferProcessor().getBlendInfo();
 
     static const uint32_t kBlendWriteShift = 1;
@@ -107,10 +115,10 @@ uint32_t GrPipeline::getBlendInfoKey() const {
     GR_STATIC_ASSERT(kLast_GrBlendCoeff < (1 << kBlendCoeffShift));
     GR_STATIC_ASSERT(kFirstAdvancedGrBlendEquation - 1 < 4);
 
-    uint32_t key = blendInfo.fWriteColor;
-    key |= (blendInfo.fSrcBlend << kBlendWriteShift);
-    key |= (blendInfo.fDstBlend << (kBlendWriteShift + kBlendCoeffShift));
-    key |= (blendInfo.fEquation << (kBlendWriteShift + 2 * kBlendCoeffShift));
+    uint32_t blendKey = blendInfo.fWriteColor;
+    blendKey |= (blendInfo.fSrcBlend << kBlendWriteShift);
+    blendKey |= (blendInfo.fDstBlend << (kBlendWriteShift + kBlendCoeffShift));
+    blendKey |= (blendInfo.fEquation << (kBlendWriteShift + 2 * kBlendCoeffShift));
 
-    return key;
+    b->add32(blendKey);
 }

src/gpu/GrPipeline.h

@@ -197,7 +197,7 @@ public:
     GrXferBarrierType xferBarrierType(GrTexture*, const GrCaps&) const;
 
     // Used by Vulkan and Metal to cache their respective pipeline objects
-    uint32_t getBlendInfoKey() const;
+    void genKey(GrProcessorKeyBuilder*, const GrCaps&) const;
 
     const GrSwizzle& outputSwizzle() const { return fOutputSwizzle; }
 

src/gpu/mtl/GrMtlPipelineStateBuilder.mm

@@ -468,7 +468,7 @@ bool GrMtlPipelineStateBuilder::Desc::Build(Desc* desc,
     b.add32((uint32_t)programInfo.pipeline().isStencilEnabled());
     // Stencil samples don't seem to be tracked in the MTLRenderPipeline
 
-    b.add32(programInfo.pipeline().getBlendInfoKey());
+    programInfo.pipeline().genKey(&b, *gpu->caps());
 
     b.add32((uint32_t)programInfo.primitiveType());
 

src/gpu/vk/GrVkCaps.cpp

@@ -461,29 +461,6 @@ void GrVkCaps::applyDriverCorrectnessWorkarounds(const VkPhysicalDevicePropertie
     }
 }
 
-int get_max_sample_count(VkSampleCountFlags flags) {
-    SkASSERT(flags & VK_SAMPLE_COUNT_1_BIT);
-    if (!(flags & VK_SAMPLE_COUNT_2_BIT)) {
-        return 0;
-    }
-    if (!(flags & VK_SAMPLE_COUNT_4_BIT)) {
-        return 2;
-    }
-    if (!(flags & VK_SAMPLE_COUNT_8_BIT)) {
-        return 4;
-    }
-    if (!(flags & VK_SAMPLE_COUNT_16_BIT)) {
-        return 8;
-    }
-    if (!(flags & VK_SAMPLE_COUNT_32_BIT)) {
-        return 16;
-    }
-    if (!(flags & VK_SAMPLE_COUNT_64_BIT)) {
-        return 32;
-    }
-    return 64;
-}
-
 void GrVkCaps::initGrCaps(const GrVkInterface* vkInterface,
                           VkPhysicalDevice physDev,
                           const VkPhysicalDeviceProperties& properties,
@@ -497,6 +474,11 @@ void GrVkCaps::initGrCaps(const GrVkInterface* vkInterface,
     static const uint32_t kMaxVertexAttributes = 64;
     fMaxVertexAttributes = SkTMin(properties.limits.maxVertexInputAttributes, kMaxVertexAttributes);
 
+    if (extensions.hasExtension(VK_EXT_SAMPLE_LOCATIONS_EXTENSION_NAME, 1)) {
+        // We "disable" multisample by colocating all samples at pixel center.
+        fMultisampleDisableSupport = true;
+    }
+
     // We could actually query and get a max size for each config, however maxImageDimension2D will
     // give the minimum max size across all configs. So for simplicity we will use that for now.
     fMaxRenderTargetSize = SkTMin(properties.limits.maxImageDimension2D, (uint32_t)INT_MAX);
@@ -1187,12 +1169,8 @@ void GrVkCaps::FormatInfo::initSampleCounts(const GrVkInterface* interface,
     if (flags & VK_SAMPLE_COUNT_16_BIT) {
         fColorSampleCounts.push_back(16);
     }
-    if (flags & VK_SAMPLE_COUNT_32_BIT) {
-        fColorSampleCounts.push_back(32);
-    }
-    if (flags & VK_SAMPLE_COUNT_64_BIT) {
-        fColorSampleCounts.push_back(64);
-    }
+    // Standard sample locations are not defined for more than 16 samples, and we don't need more
+    // than 16. Omit 32 and 64.
 }
 
 void GrVkCaps::FormatInfo::init(const GrVkInterface* interface,

src/gpu/vk/GrVkPipeline.cpp

@@ -294,6 +294,29 @@ static void setup_multisample_state(const GrProgramInfo& programInfo,
     multisampleInfo->alphaToOneEnable = VK_FALSE;
 }
 
+static void setup_all_sample_locations_at_pixel_center(
+        const GrProgramInfo& programInfo,
+        VkPipelineSampleLocationsStateCreateInfoEXT* sampleLocations) {
+    constexpr static VkSampleLocationEXT kCenteredSampleLocations[16] = {
+            {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f},
+            {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}, {.5f,.5f}};
+    memset(sampleLocations, 0, sizeof(VkPipelineSampleLocationsStateCreateInfoEXT));
+    sampleLocations->sType = VK_STRUCTURE_TYPE_PIPELINE_SAMPLE_LOCATIONS_STATE_CREATE_INFO_EXT;
+    sampleLocations->pNext = nullptr;
+    sampleLocations->sampleLocationsEnable = VK_TRUE;
+    sampleLocations->sampleLocationsInfo.sType = VK_STRUCTURE_TYPE_SAMPLE_LOCATIONS_INFO_EXT;
+    sampleLocations->sampleLocationsInfo.pNext = nullptr;
+    SkAssertResult(GrSampleCountToVkSampleCount(
+            programInfo.numSamples(),
+            &sampleLocations->sampleLocationsInfo.sampleLocationsPerPixel));
+    sampleLocations->sampleLocationsInfo.sampleLocationGridSize.width = 1;
+    sampleLocations->sampleLocationsInfo.sampleLocationGridSize.height = 1;
+    SkASSERT(programInfo.numSamples() < (int)SK_ARRAY_COUNT(kCenteredSampleLocations));
+    sampleLocations->sampleLocationsInfo.sampleLocationsCount = std::min(
+            programInfo.numSamples(), (int)SK_ARRAY_COUNT(kCenteredSampleLocations));
+    sampleLocations->sampleLocationsInfo.pSampleLocations = kCenteredSampleLocations;
+}
+
 static VkBlendFactor blend_coeff_to_vk_blend(GrBlendCoeff coeff) {
     static const VkBlendFactor gTable[] = {
         VK_BLEND_FACTOR_ZERO,                      // kZero_GrBlendCoeff
@@ -523,6 +546,15 @@ GrVkPipeline* GrVkPipeline::Create(
     VkPipelineMultisampleStateCreateInfo multisampleInfo;
     setup_multisample_state(programInfo, gpu->caps(), &multisampleInfo);
 
+    VkPipelineSampleLocationsStateCreateInfoEXT sampleLocations;
+    if (gpu->caps()->multisampleDisableSupport()) {
+        if (programInfo.numSamples() > 1 && !programInfo.pipeline().isHWAntialiasState()) {
+            setup_all_sample_locations_at_pixel_center(programInfo, &sampleLocations);
+            sampleLocations.pNext = multisampleInfo.pNext;
+            multisampleInfo.pNext = &sampleLocations;
+        }
+    }
+
     // We will only have one color attachment per pipeline.
     VkPipelineColorBlendAttachmentState attachmentStates[1];
     VkPipelineColorBlendStateCreateInfo colorBlendInfo;

src/gpu/vk/GrVkPipelineStateBuilder.cpp

@@ -346,7 +346,7 @@ bool GrVkPipelineStateBuilder::Desc::Build(Desc* desc,
 
     stencil.genKey(&b);
 
-    b.add32(programInfo.pipeline().getBlendInfoKey());
+    programInfo.pipeline().genKey(&b, *gpu->caps());
 
     // Vulkan requires the full primitive type as part of its key
     b.add32((uint32_t)programInfo.primitiveType());

src/gpu/vk/GrVkUtil.cpp

@@ -96,12 +96,6 @@ bool GrSampleCountToVkSampleCount(uint32_t samples, VkSampleCountFlagBits* vkSam
         case 16:
             *vkSamples = VK_SAMPLE_COUNT_16_BIT;
             return true;
-        case 32:
-            *vkSamples = VK_SAMPLE_COUNT_32_BIT;
-            return true;
-        case 64:
-            *vkSamples = VK_SAMPLE_COUNT_64_BIT;
-            return true;
         default:
             return false;
     }