Recycle stencil buffers across render targets.

tests/ResourceCacheTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #if SK_SUPPORT_GPU
 
 #include "GrContext.h"
@@ skipping 45 matching lines @@
         size_t curCacheSize;
         context->getResourceCacheUsage(NULL, &curCacheSize);
 
         // we should never go over the size limit
         REPORTER_ASSERT(reporter, curCacheSize <= maxCacheSize);
     }
 
     context->setResourceCacheLimits(oldMaxNum, oldMaxBytes);
 }
 
+static void test_stencil_buffers(skiatest::Reporter* reporter, GrContext* context) {
+    GrSurfaceDesc smallDesc;
+    smallDesc.fFlags = kRenderTarget_GrSurfaceFlag;
+    smallDesc.fConfig = kSkia8888_GrPixelConfig;
+    smallDesc.fWidth = 4;
+    smallDesc.fHeight = 4;
+    smallDesc.fSampleCnt = 0;
+
+    // Test that two budgeted RTs with the same desc share a stencil buffer.
+    SkAutoTUnref<GrTexture> smallRT0(context->createTexture(smallDesc, true));
+    SkAutoTUnref<GrTexture> smallRT1(context->createTexture(smallDesc, true));
+    REPORTER_ASSERT(reporter, smallRT0 && smallRT1 &&
+                              smallRT0->asRenderTarget() && smallRT1->asRenderTarget() &&
+                              smallRT0->asRenderTarget()->getStencilBuffer() ==
+                              smallRT1->asRenderTarget()->getStencilBuffer());
+
+    // An unbudgeted RT with the same desc should also share.
+    SkAutoTUnref<GrTexture> smallRT2(context->createTexture(smallDesc, false));
+    REPORTER_ASSERT(reporter, smallRT0 && smallRT2 &&
+                              smallRT0->asRenderTarget() && smallRT2->asRenderTarget() &&
+                              smallRT0->asRenderTarget()->getStencilBuffer() ==
+                              smallRT2->asRenderTarget()->getStencilBuffer());
+
+    // An RT with a much larger size should not share.
+    GrSurfaceDesc bigDesc;
+    bigDesc.fFlags = kRenderTarget_GrSurfaceFlag;
+    bigDesc.fConfig = kSkia8888_GrPixelConfig;
+    bigDesc.fWidth = 400;
+    bigDesc.fHeight = 200;
+    bigDesc.fSampleCnt = 0;
+    SkAutoTUnref<GrTexture> bigRT(context->createTexture(bigDesc, false));
+    REPORTER_ASSERT(reporter, smallRT0 && bigRT &&
+                              smallRT0->asRenderTarget() && bigRT->asRenderTarget() &&
+                              smallRT0->asRenderTarget()->getStencilBuffer() !=
+                              bigRT->asRenderTarget()->getStencilBuffer());
+
+    if (context->getMaxSampleCount() >= 4) {
+        // An RT with a different sample count should not share. 
+        GrSurfaceDesc smallMSAADesc = smallDesc;
+        smallMSAADesc.fSampleCnt = 4;
+        SkAutoTUnref<GrTexture> smallMSAART0(context->createTexture(smallMSAADesc, false));
+        REPORTER_ASSERT(reporter, smallRT0 && smallMSAART0 &&
+                                  smallRT0->asRenderTarget() && smallMSAART0->asRenderTarget() &&
+                                  smallRT0->asRenderTarget()->getStencilBuffer() !=
+                                  smallMSAART0->asRenderTarget()->getStencilBuffer());
+        // A second MSAA RT should share with the first MSAA RT.
+        SkAutoTUnref<GrTexture> smallMSAART1(context->createTexture(smallMSAADesc, false));
+        REPORTER_ASSERT(reporter, smallMSAART0 && smallMSAART1 &&
+                                  smallMSAART0->asRenderTarget() &&
+                                  smallMSAART1->asRenderTarget() &&
+                                  smallMSAART0->asRenderTarget()->getStencilBuffer() ==
+                                  smallMSAART1->asRenderTarget()->getStencilBuffer());
+        // But not one with a larger sample count should not. (Also check that the request for 4
+        // samples didn't get rounded up to >= 8 or else they could share.).
+        if (context->getMaxSampleCount() >= 8 && smallMSAART0 && smallMSAART0->asRenderTarget() &&
+            smallMSAART0->asRenderTarget()->numSamples() < 8) {
+            smallMSAADesc.fSampleCnt = 8;
+            smallMSAART1.reset(context->createTexture(smallMSAADesc, false));
+            REPORTER_ASSERT(reporter, smallMSAART0 && smallMSAART1 &&
+                                      smallMSAART0->asRenderTarget() &&
+                                      smallMSAART1->asRenderTarget() &&
+                                      smallMSAART0->asRenderTarget()->getStencilBuffer() !=
+                                      smallMSAART1->asRenderTarget()->getStencilBuffer());
+        }
+    }
+}
+
 class TestResource : public GrGpuResource {
     static const size_t kDefaultSize = 100;
     enum ScratchConstructor { kScratchConstructor };
 public:
     SK_DECLARE_INST_COUNT(TestResource);
     /** Property that distinctly categorizes the resource.
      * For example, textures have width, height, ... */
     enum SimulatedProperty { kA_SimulatedProperty, kB_SimulatedProperty };
 
     TestResource(GrGpu* gpu, size_t size, GrGpuResource::LifeCycle lifeCycle)
@@ skipping 853 matching lines @@
         }
         GrSurfaceDesc desc;
         desc.fConfig = kSkia8888_GrPixelConfig;
         desc.fFlags = kRenderTarget_GrSurfaceFlag;
         desc.fWidth = gWidth;
         desc.fHeight = gHeight;
         SkImageInfo info = SkImageInfo::MakeN32Premul(gWidth, gHeight);
         SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTarget(context,
                                                                    SkSurface::kNo_Budgeted, info));
         test_cache(reporter, context, surface->getCanvas());
+        test_stencil_buffers(reporter, context);
     }
 
     // The below tests create their own mock contexts.
     test_no_key(reporter);
     test_budgeting(reporter);
     test_unbudgeted(reporter);
     test_unbudgeted_to_scratch(reporter);
     test_duplicate_unique_key(reporter);
     test_duplicate_scratch_key(reporter);
     test_remove_scratch_key(reporter);
     test_scratch_key_consistency(reporter);
     test_purge_invalidated(reporter);
     test_cache_chained_purge(reporter);
     test_resource_size_changed(reporter);
     test_large_resource_count(reporter);
 }
 
 #endif