Vulkan: Prevent Creating ES 3.0 Context if Min. Caps. Not Met

src/libANGLE/Caps.cpp

@@ -1049,14 +1049,14 @@ Caps GenerateMinimumCaps(const Version &clientVersion, const Extensions &extensi
         caps.maxVertexAttributes                            = 16;
         caps.maxShaderUniformComponents[ShaderType::Vertex] = 1024;
         caps.maxVertexUniformVectors                        = 256;
-        caps.maxShaderUniformBlocks[ShaderType::Vertex]     = 12;
-        caps.maxVertexOutputComponents                      = 64;
+        caps.maxShaderUniformBlocks[ShaderType::Vertex]     = limits::kMinimumShaderUniformBlocks;
+        caps.maxVertexOutputComponents = limits::kMinimumVertexOutputComponents;
         caps.maxShaderTextureImageUnits[ShaderType::Vertex] = 16;
 
         // Table 6.32
         caps.maxShaderUniformComponents[ShaderType::Fragment] = 896;
         caps.maxFragmentUniformVectors                        = 224;
-        caps.maxShaderUniformBlocks[ShaderType::Fragment]     = 12;
+        caps.maxShaderUniformBlocks[ShaderType::Fragment]     = limits::kMinimumShaderUniformBlocks;
         caps.maxFragmentInputComponents                       = 60;
         caps.maxShaderTextureImageUnits[ShaderType::Fragment] = 16;
         caps.minProgramTexelOffset                            = -8;
@@ -1113,7 +1113,7 @@ Caps GenerateMinimumCaps(const Version &clientVersion, const Extensions &extensi
         caps.maxComputeWorkGroupCount                           = {{65535, 65535, 65535}};
         caps.maxComputeWorkGroupSize                            = {{128, 128, 64}};
         caps.maxComputeWorkGroupInvocations                     = 12;
-        caps.maxShaderUniformBlocks[ShaderType::Compute]        = 12;
+        caps.maxShaderUniformBlocks[ShaderType::Compute] = limits::kMinimumShaderUniformBlocks;
         caps.maxShaderTextureImageUnits[ShaderType::Compute]    = 16;
         caps.maxComputeSharedMemorySize                         = 16384;
         caps.maxShaderUniformComponents[ShaderType::Compute]    = 1024;
@@ -1154,7 +1154,7 @@ Caps GenerateMinimumCaps(const Version &clientVersion, const Extensions &extensi
 
         // Table 20.43gs (GL_EXT_geometry_shader)
         caps.maxShaderUniformComponents[ShaderType::Geometry]    = 1024;
-        caps.maxShaderUniformBlocks[ShaderType::Geometry]        = 12;
+        caps.maxShaderUniformBlocks[ShaderType::Geometry] = limits::kMinimumShaderUniformBlocks;
         caps.maxGeometryInputComponents                          = 64;
         caps.maxGeometryOutputComponents                         = 64;
         caps.maxGeometryOutputVertices                           = 256;

src/libANGLE/Constants.h

@@ -72,7 +72,7 @@ enum
     IMPLEMENTATION_MAX_ATOMIC_COUNTER_BUFFERS = 8,
 
     // Implementation upper limits, real maximums depend on the hardware.
-    IMPLEMENTATION_MAX_SHADER_STORAGE_BUFFER_BINDINGS = 64
+    IMPLEMENTATION_MAX_SHADER_STORAGE_BUFFER_BINDINGS = 64,
 };
 
 namespace limits
@@ -80,6 +80,13 @@ namespace limits
 // Some of the minimums required by GL, used to detect if the backend meets the minimum requirement.
 // Currently, there's no need to separate these values per spec version.
 constexpr uint32_t kMinimumComputeStorageBuffers = 4;
+
+// OpenGL ES 3.0+ Minimum Values
+// Table 6.31 MAX_VERTEX_UNIFORM_BLOCKS minimum value = 12
+// Table 6.32 MAX_FRAGMENT_UNIFORM_BLOCKS minimum value = 12
+constexpr uint32_t kMinimumShaderUniformBlocks = 12;
+// Table 6.31 MAX_VERTEX_OUTPUT_COMPONENTS minimum value = 64
+constexpr uint32_t kMinimumVertexOutputComponents = 64;
 }  // namespace limits
 
 }  // namespace gl

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -1227,6 +1227,7 @@ gl::Version RendererVk::getMaxSupportedESVersion() const
     }
 
     // Limit to ES2.0 if there are any blockers for 3.0.
+    // TODO: http://anglebug.com/3972 Limit to GLES 2.0 if flat shading can't be emulated
 
     // If the command buffer doesn't support queries, we can't support ES3.
     if (!vk::CommandBuffer::SupportsQueries(mPhysicalDeviceFeatures))
@@ -1250,6 +1251,29 @@ gl::Version RendererVk::getMaxSupportedESVersion() const
         maxVersion = std::max(maxVersion, gl::Version(2, 0));
     }
 
+    // Limit to GLES 2.0 if maxPerStageDescriptorUniformBuffers is too low.
+    // Table 6.31 MAX_VERTEX_UNIFORM_BLOCKS minimum value = 12
+    // Table 6.32 MAX_FRAGMENT_UNIFORM_BLOCKS minimum value = 12
+    // NOTE: We reserve some uniform buffers for emulation, so use the mNativeCaps which takes this
+    // into account, rather than the physical device maxPerStageDescriptorUniformBuffers limits.
+    for (gl::ShaderType shaderType : gl::AllShaderTypes())
+    {
+        if (mNativeCaps.maxShaderUniformBlocks[shaderType] <
+            gl::limits::kMinimumShaderUniformBlocks)
+        {
+            maxVersion = std::max(maxVersion, gl::Version(2, 0));
+        }
+    }
+
+    // Limit to GLES 2.0 if maxVertexOutputComponents is too low.
+    // Table 6.31 MAX VERTEX OUTPUT COMPONENTS minimum value = 64
+    // NOTE: We reserve some vertex output components for emulation, so use the mNativeCaps which
+    // takes this into account, rather than the physical device maxVertexOutputComponents limits.
+    if (mNativeCaps.maxVertexOutputComponents < gl::limits::kMinimumVertexOutputComponents)
+    {
+        maxVersion = std::max(maxVersion, gl::Version(2, 0));
+    }
+
     return maxVersion;
 }