Vulkan: Disallow multisampling with a sample count of 1

src/libANGLE/renderer/vulkan/vk_caps_utils.cpp

@@ -160,15 +160,21 @@ void RendererVk::ensureCapsInitialized() const
 
     mNativeCaps.maxDrawBuffers =
         std::min(limitsVk.maxColorAttachments, limitsVk.maxFragmentOutputAttachments);
-    mNativeCaps.maxFramebufferWidth    = LimitToInt(limitsVk.maxFramebufferWidth);
-    mNativeCaps.maxFramebufferHeight   = LimitToInt(limitsVk.maxFramebufferHeight);
-    mNativeCaps.maxColorAttachments    = LimitToInt(limitsVk.maxColorAttachments);
-    mNativeCaps.maxViewportWidth       = LimitToInt(limitsVk.maxViewportDimensions[0]);
-    mNativeCaps.maxViewportHeight      = LimitToInt(limitsVk.maxViewportDimensions[1]);
-    mNativeCaps.maxSampleMaskWords     = LimitToInt(limitsVk.maxSampleMaskWords);
-    mNativeCaps.maxColorTextureSamples = limitsVk.sampledImageColorSampleCounts;
-    mNativeCaps.maxDepthTextureSamples = limitsVk.sampledImageDepthSampleCounts;
-    mNativeCaps.maxIntegerSamples      = limitsVk.sampledImageIntegerSampleCounts;
+    mNativeCaps.maxFramebufferWidth  = LimitToInt(limitsVk.maxFramebufferWidth);
+    mNativeCaps.maxFramebufferHeight = LimitToInt(limitsVk.maxFramebufferHeight);
+    mNativeCaps.maxColorAttachments  = LimitToInt(limitsVk.maxColorAttachments);
+    mNativeCaps.maxViewportWidth     = LimitToInt(limitsVk.maxViewportDimensions[0]);
+    mNativeCaps.maxViewportHeight    = LimitToInt(limitsVk.maxViewportDimensions[1]);
+    mNativeCaps.maxSampleMaskWords   = LimitToInt(limitsVk.maxSampleMaskWords);
+    mNativeCaps.maxColorTextureSamples =
+        limitsVk.sampledImageColorSampleCounts & vk_gl::kSupportedSampleCounts;
+    mNativeCaps.maxDepthTextureSamples =
+        limitsVk.sampledImageDepthSampleCounts & vk_gl::kSupportedSampleCounts;
+    // TODO (ianelliott): Should mask this with vk_gl::kSupportedSampleCounts, but it causes
+    // end2end test failures with SwiftShader because SwiftShader returns a sample count of 1 in
+    // sampledImageIntegerSampleCounts.
+    // See: http://anglebug.com/4197
+    mNativeCaps.maxIntegerSamples = limitsVk.sampledImageIntegerSampleCounts;
 
     mNativeCaps.maxVertexAttributes     = LimitToInt(limitsVk.maxVertexInputAttributes);
     mNativeCaps.maxVertexAttribBindings = LimitToInt(limitsVk.maxVertexInputBindings);
@@ -440,9 +446,9 @@ void RendererVk::ensureCapsInitialized() const
     mNativeCaps.minProgramTexelOffset = limitsVk.minTexelOffset;
     mNativeCaps.maxProgramTexelOffset = LimitToInt(limitsVk.maxTexelOffset);
 
-    const uint32_t sampleCounts = limitsVk.framebufferColorSampleCounts &
-                                  limitsVk.framebufferDepthSampleCounts &
-                                  limitsVk.framebufferStencilSampleCounts;
+    const uint32_t sampleCounts =
+        limitsVk.framebufferColorSampleCounts & limitsVk.framebufferDepthSampleCounts &
+        limitsVk.framebufferStencilSampleCounts & vk_gl::kSupportedSampleCounts;
 
     mNativeCaps.maxSamples            = LimitToInt(vk_gl::GetMaxSampleCount(sampleCounts));
     mNativeCaps.maxFramebufferSamples = mNativeCaps.maxSamples;
@@ -603,10 +609,12 @@ egl::ConfigSet GenerateConfigs(const GLenum *colorFormats,
 
     const VkPhysicalDeviceLimits &limits =
         display->getRenderer()->getPhysicalDeviceProperties().limits;
-    const uint32_t depthStencilSampleCountsLimit =
-        limits.framebufferDepthSampleCounts & limits.framebufferStencilSampleCounts;
+    const uint32_t depthStencilSampleCountsLimit = limits.framebufferDepthSampleCounts &
+                                                   limits.framebufferStencilSampleCounts &
+                                                   vk_gl::kSupportedSampleCounts;
 
-    vk_gl::AddSampleCounts(limits.framebufferColorSampleCounts, &colorSampleCounts);
+    vk_gl::AddSampleCounts(limits.framebufferColorSampleCounts & vk_gl::kSupportedSampleCounts,
+                           &colorSampleCounts);
     vk_gl::AddSampleCounts(depthStencilSampleCountsLimit, &depthStencilSampleCounts);
 
     // Always support 0 samples

src/libANGLE/renderer/vulkan/vk_utils.cpp

@@ -867,7 +867,7 @@ void AddSampleCounts(VkSampleCountFlags sampleCounts, gl::SupportedSampleSet *se
 {
     // The possible bits are VK_SAMPLE_COUNT_n_BIT = n, with n = 1 << b.  At the time of this
     // writing, b is in [0, 6], however, we test all 32 bits in case the enum is extended.
-    for (size_t bit : angle::BitSet32<32>(sampleCounts))
+    for (size_t bit : angle::BitSet32<32>(sampleCounts & kSupportedSampleCounts))
     {
         setOut->insert(static_cast<GLuint>(1 << bit));
     }
@@ -876,7 +876,7 @@ void AddSampleCounts(VkSampleCountFlags sampleCounts, gl::SupportedSampleSet *se
 GLuint GetMaxSampleCount(VkSampleCountFlags sampleCounts)
 {
     GLuint maxCount = 0;
-    for (size_t bit : angle::BitSet32<32>(sampleCounts))
+    for (size_t bit : angle::BitSet32<32>(sampleCounts & kSupportedSampleCounts))
     {
         maxCount = static_cast<GLuint>(1 << bit);
     }
@@ -885,7 +885,7 @@ GLuint GetMaxSampleCount(VkSampleCountFlags sampleCounts)
 
 GLuint GetSampleCount(VkSampleCountFlags supportedCounts, GLuint requestedCount)
 {
-    for (size_t bit : angle::BitSet32<32>(supportedCounts))
+    for (size_t bit : angle::BitSet32<32>(supportedCounts & kSupportedSampleCounts))
     {
         GLuint sampleCount = static_cast<GLuint>(1 << bit);
         if (sampleCount >= requestedCount)

src/libANGLE/renderer/vulkan/vk_utils.h

@@ -656,6 +656,20 @@ void GetExtentsAndLayerCount(gl::TextureType textureType,
 
 namespace vk_gl
 {
+// The Vulkan back-end will not support a sample count of 1, because of a Vulkan specification
+// restriction:
+//
+//   If the image was created with VkImageCreateInfo::samples equal to VK_SAMPLE_COUNT_1_BIT, the
+//   instruction must: have MS = 0.
+//
+// This restriction was tracked in http://anglebug.com/4196 and Khronos-private Vulkan
+// specification issue https://gitlab.khronos.org/vulkan/vulkan/issues/1925.
+//
+// In addition, the Vulkan back-end will not support sample counts of 32 or 64, since there are no
+// standard sample locations for those sample counts.
+constexpr unsigned int kSupportedSampleCounts = (VK_SAMPLE_COUNT_2_BIT | VK_SAMPLE_COUNT_4_BIT |
+                                                 VK_SAMPLE_COUNT_8_BIT | VK_SAMPLE_COUNT_16_BIT);
+
 // Find set bits in sampleCounts and add the corresponding sample count to the set.
 void AddSampleCounts(VkSampleCountFlags sampleCounts, gl::SupportedSampleSet *outSet);
 // Return the maximum sample count with a bit set in |sampleCounts|.

src/tests/deqp_support/deqp_gles31_test_expectations.txt

@@ -656,21 +656,8 @@
 // Need to support non-color when staging image updates
 4080 ANDROID VULKAN : dEQP-GLES31.functional.stencil_texturing.misc.base_level = SKIP
 
-//// Multisampled textures:
-// The following tests pass, but fail because of Vulkan validation-layer errors, which are the result
-// of a Vulkan spec statement that 1-sample textures can't be used with multisample shaders.
-// Issue 4197 tracks the external dependencies (Vulkan spec and validation-layer changes).
-4197 VULKAN : dEQP-GLES31.functional.texture.multisample.samples_1.sample_position = FAIL
-4197 VULKAN : dEQP-GLES31.functional.texture.multisample.samples_1.sample_mask* = FAIL
-4197 VULKAN : dEQP-GLES31.functional.texture.multisample.samples_1.use_texture_*_2d = FAIL
-4197 VULKAN : dEQP-GLES31.functional.shaders.builtin_functions.texture_size.samples_1_texture_2d = FAIL
-4197 VULKAN : dEQP-GLES31.functional.shaders.builtin_functions.texture_size.samples_1_texture_int_2d = FAIL
-4197 VULKAN : dEQP-GLES31.functional.shaders.builtin_functions.texture_size.samples_1_texture_uint_2d = FAIL
-
-// The following tests cause an assert within SwiftShader because a sample count of 1 is used with alpha:
-4212 SWIFTSHADER : dEQP-GLES31.functional.texture.multisample.samples_1.sample_mask_and*alpha_to_coverage = SKIP
-
 // The following are failing because of pixel/sub-pixel rendering differences than what is expected:
+4213 SWIFTSHADER : dEQP-GLES31.functional.texture.multisample.samples_1.sample_position = FAIL
 4213 SWIFTSHADER : dEQP-GLES31.functional.texture.multisample.samples_2.sample_position = FAIL
 4213 SWIFTSHADER : dEQP-GLES31.functional.texture.multisample.samples_3.sample_position = FAIL
 4213 SWIFTSHADER : dEQP-GLES31.functional.texture.multisample.samples_4.sample_position = FAIL