Fix GrDefaultPathRender inversely wound path bug

Bug: 769898
Change-Id: I3b1a43b1e114b35105493a0cfa01a1f01b65fa56
Reviewed-on: https://skia-review.googlesource.com/64065
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

3 files changed, 169 insertions, 18 deletions

diff --git a/tests/DefaultPathRendererTest.cpp b/tests/DefaultPathRendererTest.cpp
new file mode 100644
index 0000000000..d1e102bc5e
--- /dev/null
+++ b/tests/DefaultPathRendererTest.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+
+#if SK_SUPPORT_GPU
+#include "GrClip.h"
+#include "GrRenderTargetContext.h"
+#include "GrStyle.h"
+#include "GrTypesPriv.h"
+
+#include "effects/GrConstColorProcessor.h"
+
+static void allow_default_and_msaa(GrContextOptions* options) {
+    options->fGpuPathRenderers = GpuPathRenderers::kMSAA;
+}
+
+static void only_allow_default(GrContextOptions* options) {
+    options->fGpuPathRenderers = GpuPathRenderers::kNone;
+}
+
+static SkBitmap read_back(GrRenderTargetContext* rtc, int width, int height) {
+
+    SkImageInfo dstII = SkImageInfo::MakeN32Premul(width, height);
+
+    SkBitmap bm;
+    bm.allocPixels(dstII);
+
+    rtc->readPixels(dstII, bm.getAddr(0, 0), bm.rowBytes(), 0, 0, 0);
+
+    return bm;
+}
+
+static SkPath make_path(const SkRect& outer, int inset, SkPath::FillType fill) {
+    SkPath p;
+
+    p.addRect(outer, SkPath::kCW_Direction);
+    p.addRect(outer.makeInset(inset, inset), SkPath::kCCW_Direction);
+    p.setFillType(fill);
+    return p;
+}
+
+
+static const int kBigSize = 64; // This should be a power of 2
+static const int kPad = 3;
+
+// From crbug.com/769898:
+//   create an approx fit render target context that will have extra space (i.e., npot)
+//   draw an inverse wound concave path into it - forcing use of the stencil-using path renderer
+//   throw the RTC away so the backing GrSurface/GrStencilBuffer can be reused
+//   create a new render target context that will reuse the prior GrSurface
+//   draw a normally wound concave path that touches outside of the approx fit RTC's content rect
+//
+// When the bug manifests the GrDefaultPathRenderer/GrMSAAPathRenderer is/was leaving the stencil
+// buffer outside of the first content rect in a bad state and the second draw would be incorrect.
+
+static void run_test(GrContext* ctx, skiatest::Reporter* reporter) {
+    SkPath invPath = make_path(SkRect::MakeXYWH(0, 0, kBigSize, kBigSize),
+                               kBigSize/2-1, SkPath::kInverseWinding_FillType);
+    SkPath path = make_path(SkRect::MakeXYWH(0, 0, kBigSize, kBigSize),
+                            kPad, SkPath::kWinding_FillType);
+
+    GrStyle style(SkStrokeRec::kFill_InitStyle);
+
+    {
+        auto rtc =  ctx->makeDeferredRenderTargetContext(SkBackingFit::kApprox,
+                                                         kBigSize/2+1, kBigSize/2+1,
+                                                         kRGBA_8888_GrPixelConfig, nullptr);
+
+        rtc->clear(nullptr, GrColorPackRGBA(0x0, 0x0, 0x0, 0xFF), true);
+
+        GrPaint paint;
+
+        const GrColor4f color = { 1.0f, 0.0f, 0.0f, 1.0f };
+        auto fp = GrConstColorProcessor::Make(color, GrConstColorProcessor::kIgnore_InputMode);
+        paint.addColorFragmentProcessor(std::move(fp));
+
+        rtc->drawPath(GrNoClip(), std::move(paint), GrAA::kNo,
+                      SkMatrix::I(), invPath, style);
+
+        rtc->prepareForExternalIO(0, nullptr);
+    }
+
+    {
+        auto rtc = ctx->makeDeferredRenderTargetContext(SkBackingFit::kExact, kBigSize, kBigSize,
+                                                        kRGBA_8888_GrPixelConfig, nullptr);
+
+        rtc->clear(nullptr, GrColorPackRGBA(0x0, 0x0, 0x0, 0xFF), true);
+
+        GrPaint paint;
+
+        const GrColor4f color = { 0.0f, 1.0f, 0.0f, 1.0f };
+        auto fp = GrConstColorProcessor::Make(color, GrConstColorProcessor::kIgnore_InputMode);
+        paint.addColorFragmentProcessor(std::move(fp));
+
+        rtc->drawPath(GrNoClip(), std::move(paint), GrAA::kNo,
+                      SkMatrix::I(), path, style);
+
+        SkBitmap bm = read_back(rtc.get(), kBigSize, kBigSize);
+
+        bool correct = true;
+        for (int y = kBigSize/2+1; y < kBigSize-kPad-1 && correct; ++y) {
+            for (int x = kPad+1; x < kBigSize-kPad-1 && correct; ++x) {
+                correct = bm.getColor(x, y) == SK_ColorBLACK;
+                REPORTER_ASSERT(reporter, correct);
+            }
+        }
+    }
+
+}
+
+DEF_GPUTEST_FOR_CONTEXTS(GrDefaultPathRendererTest,
+                         sk_gpu_test::GrContextFactory::IsRenderingContext,
+                         reporter, ctxInfo, only_allow_default) {
+    GrContext* ctx = ctxInfo.grContext();
+
+    run_test(ctx, reporter);
+}
+
+DEF_GPUTEST_FOR_CONTEXTS(GrMSAAPathRendererTest,
+                         sk_gpu_test::GrContextFactory::IsRenderingContext,
+                         reporter, ctxInfo, allow_default_and_msaa) {
+    GrContext* ctx = ctxInfo.grContext();
+
+    if (!ctx->caps()->sampleShadingSupport()) {   // The MSAAPathRenderer requires this
+        return;
+    }
+
+    run_test(ctx, reporter);
+}
+
+#endif
diff --git a/tests/ResourceCacheTest.cpp b/tests/ResourceCacheTest.cpp
index 0cb1d2b269..863830aefe 100644
--- a/tests/ResourceCacheTest.cpp
+++ b/tests/ResourceCacheTest.cpp
@@ -120,7 +120,7 @@ static sk_sp<GrRenderTarget> create_RT_with_SB(GrResourceProvider* provider,
 
 // This currently fails on ES3 ANGLE contexts
 DEF_GPUTEST_FOR_CONTEXTS(ResourceCacheStencilBuffers, &is_rendering_and_not_angle_es3, reporter,
-                         ctxInfo) {
+                         ctxInfo, nullptr) {
     GrContext* context = ctxInfo.grContext();
     if (context->caps()->avoidStencilBuffers()) {
         return;
diff --git a/tests/Test.h b/tests/Test.h
index c9a381eb12..7ef29325b7 100644
--- a/tests/Test.h
+++ b/tests/Test.h
@@ -22,6 +22,7 @@ class ContextInfo;
 class GLTestContext;
 }  // namespace sk_gpu_test
 class GrContext;
+class GrContextOptions;
 #endif
 
 namespace skiatest {
@@ -89,12 +90,21 @@ private:
 };
 
 typedef void (*TestProc)(skiatest::Reporter*, sk_gpu_test::GrContextFactory*);
+typedef void (*ContextOptionsProc)(GrContextOptions*);
 
 struct Test {
-    Test(const char* n, bool g, TestProc p) : name(n), needsGpu(g), proc(p) {}
+    Test(const char* n, bool g, TestProc p, ContextOptionsProc optionsProc = nullptr)
+        : name(n), needsGpu(g), proc(p), fContextOptionsProc(optionsProc) {}
     const char* name;
     bool needsGpu;
     TestProc proc;
+    ContextOptionsProc fContextOptionsProc;
+
+    void modifyGrContextOptions(GrContextOptions* options) {
+        if (fContextOptionsProc) {
+            (*fContextOptionsProc)(options);
+        }
+    }
 
     void run(skiatest::Reporter* r, sk_gpu_test::GrContextFactory* factory) const {
         TRACE_EVENT1("test", TRACE_FUNC, "name", this->name/*these are static*/);
@@ -200,31 +210,36 @@ private:
             skiatest::Test(#name, true, test_##name));                                       \
     void test_##name(skiatest::Reporter* reporter, sk_gpu_test::GrContextFactory* factory)
 
-#define DEF_GPUTEST_FOR_CONTEXTS(name, context_filter, reporter, context_info)            \
-    static void test_##name(skiatest::Reporter*,                                          \
-                            const sk_gpu_test::ContextInfo& context_info);                \
-    static void test_gpu_contexts_##name(skiatest::Reporter* reporter,                    \
-                                         sk_gpu_test::GrContextFactory* factory) {        \
-        skiatest::RunWithGPUTestContexts(test_##name, context_filter, reporter, factory); \
-    }                                                                                     \
-    skiatest::TestRegistry name##TestRegistry(                                            \
-            skiatest::Test(#name, true, test_gpu_contexts_##name));                       \
-    void test_##name(skiatest::Reporter* reporter,                                        \
+#define DEF_GPUTEST_FOR_CONTEXTS(name, context_filter, reporter, context_info, options_filter)  \
+    static void test_##name(skiatest::Reporter*,                                                \
+                            const sk_gpu_test::ContextInfo& context_info);                      \
+    static void test_gpu_contexts_##name(skiatest::Reporter* reporter,                          \
+                                         sk_gpu_test::GrContextFactory* factory) {              \
+        skiatest::RunWithGPUTestContexts(test_##name, context_filter, reporter, factory);       \
+    }                                                                                           \
+    skiatest::TestRegistry name##TestRegistry(                                                  \
+            skiatest::Test(#name, true, test_gpu_contexts_##name, options_filter));             \
+    void test_##name(skiatest::Reporter* reporter,                                              \
                      const sk_gpu_test::ContextInfo& context_info)
 
 #define DEF_GPUTEST_FOR_ALL_CONTEXTS(name, reporter, context_info)                          \
-        DEF_GPUTEST_FOR_CONTEXTS(name, nullptr, reporter, context_info)
+        DEF_GPUTEST_FOR_CONTEXTS(name, nullptr, reporter, context_info, nullptr)
+
 #define DEF_GPUTEST_FOR_RENDERING_CONTEXTS(name, reporter, context_info)                    \
         DEF_GPUTEST_FOR_CONTEXTS(name, sk_gpu_test::GrContextFactory::IsRenderingContext,   \
-                                 reporter, context_info)
+                                 reporter, context_info, nullptr)
 #define DEF_GPUTEST_FOR_ALL_GL_CONTEXTS(name, reporter, context_info)                       \
-        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsGLContextType, reporter, context_info)
+        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsGLContextType,                          \
+                                 reporter, context_info, nullptr)
 #define DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(name, reporter, context_info)                 \
-        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsRenderingGLContextType, reporter, context_info)
+        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsRenderingGLContextType,                 \
+                                 reporter, context_info, nullptr)
 #define DEF_GPUTEST_FOR_NULLGL_CONTEXT(name, reporter, context_info)                        \
-        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsNullGLContextType, reporter, context_info)
+        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsNullGLContextType,                      \
+                                 reporter, context_info, nullptr)
 #define DEF_GPUTEST_FOR_VULKAN_CONTEXT(name, reporter, context_info)                        \
-        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsVulkanContextType, reporter, context_info)
+        DEF_GPUTEST_FOR_CONTEXTS(name, &skiatest::IsVulkanContextType,                      \
+                                 reporter, context_info, nullptr)
 
 #define REQUIRE_PDF_DOCUMENT(TEST_NAME, REPORTER)                          \
     do {                                                                   \