Lots of little cleanup improvements to Vulkan

src/gpu/vk/GrVkGpuCommandBuffer.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "GrVkGpuCommandBuffer.h"
 
 #include "GrFixedClip.h"
@@ skipping 39 matching lines @@
             *storeOp = VK_ATTACHMENT_STORE_OP_STORE;
     }
 }
 
 GrVkGpuCommandBuffer::GrVkGpuCommandBuffer(GrVkGpu* gpu,
                                            GrVkRenderTarget* target,
                                            const LoadAndStoreInfo& colorInfo,
                                            const LoadAndStoreInfo& stencilInfo)
     : fGpu(gpu)
     , fRenderTarget(target)
-    , fIsEmpty(true) {
+    , fIsEmpty(true)
+    , fStartsWithClear(false) {
     VkAttachmentLoadOp vkLoadOp;
     VkAttachmentStoreOp vkStoreOp;
 
     get_vk_load_store_ops(colorInfo, &vkLoadOp, &vkStoreOp);
     GrVkRenderPass::LoadStoreOps vkColorOps(vkLoadOp, vkStoreOp);
 
     get_vk_load_store_ops(stencilInfo, &vkLoadOp, &vkStoreOp);
     GrVkRenderPass::LoadStoreOps vkStencilOps(vkLoadOp, vkStoreOp);
 
     GrVkRenderPass::LoadStoreOps vkResolveOps(VK_ATTACHMENT_LOAD_OP_LOAD,
@@ skipping 23 matching lines @@
     fRenderPass->unref(fGpu);
 }
 
 GrGpu* GrVkGpuCommandBuffer::gpu() { return fGpu; }
 
 void GrVkGpuCommandBuffer::end() {
     fCommandBuffer->end(fGpu);
 }
 
 void GrVkGpuCommandBuffer::onSubmit(const SkIRect& bounds) {
+    if (fIsEmpty && !fStartsWithClear) {
+        // We have sumbitted no actual draw commands to the command buffer and we are not using
+        // the render pass to do a clear so there is no need to submit anything.
+        return;
+    }
+
     // Change layout of our render target so it can be used as the color attachment. Currently
     // we don't attach the resolve to the framebuffer so no need to change its layout.
     GrVkImage* targetImage = fRenderTarget->msaaImage() ? fRenderTarget->msaaImage()
                                                         : fRenderTarget;
     targetImage->setImageLayout(fGpu,
                                 VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
                                 VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
                                 VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
                                 false);
 
@@ skipping 34 matching lines @@
                                                                   vkStencilOps);
         } else {
             fRenderPass = fGpu->resourceProvider().findRenderPass(*vkRT,
                                                                   vkColorOps,
                                                                   vkResolveOps,
                                                                   vkStencilOps);
         }
 
         SkASSERT(fRenderPass->isCompatible(*oldRP));
         oldRP->unref(fGpu);
+        fStartsWithClear = false;
     }
 }
 
 void GrVkGpuCommandBuffer::onClearStencilClip(GrRenderTarget* target,
                                               const GrFixedClip& clip,
                                               bool insideStencilMask) {
     SkASSERT(target);
     SkASSERT(!clip.hasWindowRectangles());
 
     GrVkRenderTarget* vkRT = static_cast<GrVkRenderTarget*>(target);
@@ skipping 77 matching lines @@
             fRenderPass = fGpu->resourceProvider().findRenderPass(*vkRT,
                                                                   vkColorOps,
                                                                   vkResolveOps,
                                                                   vkStencilOps);
         }
 
         SkASSERT(fRenderPass->isCompatible(*oldRP));
         oldRP->unref(fGpu);
 
         GrColorToRGBAFloat(color, fColorClearValue.color.float32);
+        fStartsWithClear = true;
         return;
     }
 
     // We always do a sub rect clear with clearAttachments since we are inside a render pass
     VkClearRect clearRect;
     // Flip rect if necessary
     SkIRect vkRect;
     if (!clip.scissorEnabled()) {
         vkRect.setXYWH(0, 0, vkRT->width(), vkRT->height());
     } else if (kBottomLeft_GrSurfaceOrigin != vkRT->origin()) {
@@ skipping 171 matching lines @@
             fGpu->stats()->incNumDraws();
         } while ((nonIdxMesh = iter.next()));
     }
 
     // Technically we don't have to call this here (since there is a safety check in
     // pipelineState:setData but this will allow for quicker freeing of resources if the
     // pipelineState sits in a cache for a while.
     pipelineState->freeTempResources(fGpu);
 }