Unify DescriptorPools for vulkan uniform descriptor sets

src/gpu/vk/GrVkResourceProvider.h

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #ifndef GrVkResourceProvider_DEFINED
 #define GrVkResourceProvider_DEFINED
 
@@ skipping 52 matching lines @@
 
     // Finds or creates a compatible GrVkSampler based on the GrTextureParams.
     // The refcount is incremented and a pointer returned.
     GrVkSampler* findOrCreateCompatibleSampler(const GrTextureParams&, uint32_t mipLevels);
 
     sk_sp<GrVkPipelineState> findOrCreateCompatiblePipelineState(const GrPipeline&,
                                                                  const GrPrimitiveProcessor&,
                                                                  GrPrimitiveType,
                                                                  const GrVkRenderPass& renderPass);
 
+    // For all our GrVkPipelineState objects, we require a layout where the first set contains two
+    // uniform buffers, one for the vertex shader and one for the fragment shader. Thus it is
+    // possible for us to use a shadered descriptor pool to allocate all these similar descriptor
+    // sets. The caller is responsible for reffing the outPool for as long as the returned
+    // VkDescriptor set is in use.
+    void getUniformDescriptorSet(VkDescriptorSet*, const GrVkDescriptorPool** outPool);
+
+    // Returns the compatible VkDescriptorSetLayout to use for uniform buffers. The caller does not
+    // own the VkDescriptorSetLayout and thus should not delete it. This function should be used
+    // when the caller needs the layout to create a VkPipelineLayout.
+    VkDescriptorSetLayout getUniDSLayout() const { return fUniformDescLayout; }
+
     // Destroy any cached resources. To be called before destroying the VkDevice.
     // The assumption is that all queues are idle and all command buffers are finished.
     // For resource tracing to work properly, this should be called after unrefing all other
     // resource usages.
     void destroyResources();
 
     // Abandon any cached resources. To be used when the context/VkDevice is lost.
     // For resource tracing to work properly, this should be called after unrefing all other
     // resource usages.
     void abandonResources();
@@ skipping 32 matching lines @@
         SkTInternalLList<Entry> fLRUList;
 
         GrVkGpu*                    fGpu;
 
 #ifdef GR_PIPELINE_STATE_CACHE_STATS
         int                         fTotalRequests;
         int                         fCacheMisses;
 #endif
     };
 
+    // Initialiaze the vkDescriptorSetLayout used for allocating new uniform buffer descritpor sets.
+    void initUniformDescObjects();
+
     GrVkGpu* fGpu;
 
     // Central cache for creating pipelines
     VkPipelineCache fPipelineCache;
 
     // Array of RenderPasses that only have a single color attachment, optional stencil attachment,
     // optional resolve attachment, and only one subpass
     SkSTArray<4, GrVkRenderPass*> fSimpleRenderPasses;
 
     // Array of CommandBuffers that are currently in flight
     SkSTArray<4, GrVkCommandBuffer*> fActiveCommandBuffers;
 
     // Stores GrVkSampler objects that we've already created so we can reuse them across multiple
     // GrVkPipelineStates
     SkTDynamicHash<GrVkSampler, uint16_t> fSamplers;
 
     // Cache of GrVkPipelineStates
     PipelineStateCache* fPipelineStateCache;
+
+    // Current pool to allocate uniform descriptor sets from
+    const GrVkDescriptorPool* fUniformDescPool;
+    VkDescriptorSetLayout  fUniformDescLayout;
+    //Curent number of uniform descriptors allocated from the pool
+    int                fCurrentUniformDescCount;
+    int                fCurrMaxUniDescriptors;
+    static const int   kMaxUniformDescriptors = 1024;

[jvanverth1, 2016/04/28 20:34:30]

I believe that Chrome would prefer that these be enums rather than initialized
in the header. See the "static const members vs enums" discussion in
chromium-dev.

+    static const int   kNumUniformDescPerSet = 2;
 };
 
 #endif