ccpr: Update the sample to use proper coverage count buffers

Bug: skia:
Change-Id: I6ce3ec567e671fa2ab3f05403015b48251518227
Reviewed-on: https://skia-review.googlesource.com/115072
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>

5 files changed, 66 insertions, 21 deletions

diff --git a/samplecode/SampleCCPRGeometry.cpp b/samplecode/SampleCCPRGeometry.cpp
index 4b521dea48..4d4bfcf49e 100644
--- a/samplecode/SampleCCPRGeometry.cpp
+++ b/samplecode/SampleCCPRGeometry.cpp
@@ -49,7 +49,8 @@ public:
 
 private:
     class Click;
-    class Op;
+    class DrawCoverageCountOp;
+    class VisualizeCoverageCountFP;
 
     void updateAndInval() { this->updateGpuData(); }
 
@@ -68,15 +69,17 @@ private:
     typedef SampleView INHERITED;
 };
 
-class CCPRGeometryView::Op : public GrDrawOp {
+class CCPRGeometryView::DrawCoverageCountOp : public GrDrawOp {
     DEFINE_OP_CLASS_ID
 
 public:
-    Op(CCPRGeometryView* view) : INHERITED(ClassID()), fView(view) {
+    DrawCoverageCountOp(CCPRGeometryView* view) : INHERITED(ClassID()), fView(view) {
         this->setBounds(SkRectPriv::MakeLargest(), GrOp::HasAABloat::kNo, GrOp::IsZeroArea::kNo);
     }
 
-    const char* name() const override { return "[Testing/Sample code] CCPRGeometryView::Op"; }
+    const char* name() const override {
+        return "[Testing/Sample code] CCPRGeometryView::DrawCoverageCountOp";
+    }
 
 private:
     FixedFunctionFlags fixedFunctionFlags() const override { return FixedFunctionFlags::kNone; }
@@ -94,6 +97,32 @@ private:
     typedef GrDrawOp INHERITED;
 };
 
+class CCPRGeometryView::VisualizeCoverageCountFP : public GrFragmentProcessor {
+public:
+    VisualizeCoverageCountFP() : GrFragmentProcessor(kTestFP_ClassID, kNone_OptimizationFlags) {}
+
+private:
+    const char* name() const override {
+        return "[Testing/Sample code] CCPRGeometryView::VisualizeCoverageCountFP";
+    }
+    std::unique_ptr<GrFragmentProcessor> clone() const override {
+        return skstd::make_unique<VisualizeCoverageCountFP>();
+    }
+    void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
+    bool onIsEqual(const GrFragmentProcessor&) const override { return true; }
+
+    class Impl : public GrGLSLFragmentProcessor {
+        void emitCode(EmitArgs& args) override {
+            GrGLSLFPFragmentBuilder* f = args.fFragBuilder;
+            f->codeAppendf("half count = %s.a;", args.fInputColor);
+            f->codeAppendf("%s = half4(clamp(-count, 0, 1), clamp(+count, 0, 1), 0, abs(count));",
+                           args.fOutputColor);
+        }
+    };
+
+    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override { return new Impl; }
+};
+
 static void draw_klm_line(int w, int h, SkCanvas* canvas, const SkScalar line[3], SkColor color) {
     SkPoint p1, p2;
     if (SkScalarAbs(line[1]) > SkScalarAbs(line[0])) {
@@ -153,7 +182,29 @@ void CCPRGeometryView::onDrawContent(SkCanvas* canvas) {
 
     SkString caption;
     if (GrRenderTargetContext* rtc = canvas->internal_private_accessTopLayerRenderTargetContext()) {
-        rtc->priv().testingOnly_addDrawOp(skstd::make_unique<Op>(this));
+        // Render coverage count.
+        GrContext* ctx = canvas->getGrContext();
+        SkASSERT(ctx);
+        sk_sp<GrRenderTargetContext> ccbuff =
+                ctx->contextPriv().makeDeferredRenderTargetContext(SkBackingFit::kApprox,
+                                                                   this->width(), this->height(),
+                                                                   kAlpha_half_GrPixelConfig,
+                                                                   nullptr);
+        SkASSERT(ccbuff);
+        ccbuff->clear(nullptr, 0, GrRenderTargetContext::CanClearFullscreen::kYes);
+        ccbuff->priv().testingOnly_addDrawOp(skstd::make_unique<DrawCoverageCountOp>(this));
+
+        // Visualize coverage count in main canvas.
+        GrPaint paint;
+        paint.addColorFragmentProcessor(
+                GrSimpleTextureEffect::Make(sk_ref_sp(ccbuff->asTextureProxy()), SkMatrix::I()));
+        paint.addColorFragmentProcessor(
+                skstd::make_unique<VisualizeCoverageCountFP>());
+        paint.setPorterDuffXPFactory(SkBlendMode::kSrcOver);
+        rtc->drawRect(GrNoClip(), std::move(paint), GrAA::kNo, SkMatrix::I(),
+                      SkRect::MakeIWH(this->width(), this->height()));
+
+        // Add label.
         caption.appendf("RenderPass_%s", GrCCCoverageProcessor::RenderPassName(fRenderPass));
         if (RenderPass::kCubics == fRenderPass) {
             caption.appendf(" (%s)", SkCubicTypeName(fCubicType));
@@ -238,7 +289,7 @@ void CCPRGeometryView::updateGpuData() {
     }
 }
 
-void CCPRGeometryView::Op::onExecute(GrOpFlushState* state) {
+void CCPRGeometryView::DrawCoverageCountOp::onExecute(GrOpFlushState* state) {
     this->drawRenderPass(state, fView->fRenderPass);
 
     RenderPass cornerPass = RenderPass((int)fView->fRenderPass + 1);
@@ -247,7 +298,8 @@ void CCPRGeometryView::Op::onExecute(GrOpFlushState* state) {
     }
 }
 
-void CCPRGeometryView::Op::drawRenderPass(GrOpFlushState* state, RenderPass renderPass) {
+void CCPRGeometryView::DrawCoverageCountOp::drawRenderPass(GrOpFlushState* state,
+                                                           RenderPass renderPass) {
     GrResourceProvider* rp = state->resourceProvider();
     GrContext* context = state->gpu()->getContext();
     GrGLGpu* glGpu = kOpenGL_GrBackend == context->contextPriv().getBackend()
@@ -255,7 +307,7 @@ void CCPRGeometryView::Op::drawRenderPass(GrOpFlushState* state, RenderPass rend
                              : nullptr;
 
     GrCCCoverageProcessor proc(rp, renderPass, GrCCCoverageProcessor::WindMethod::kCrossProduct);
-    SkDEBUGCODE(proc.enableDebugVisualizations(kDebugBloat));
+    SkDEBUGCODE(proc.enableDebugBloat(kDebugBloat));
 
     SkSTArray<1, GrMesh> mesh;
     if (RenderPass::kCubics == renderPass) {
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor.cpp b/src/gpu/ccpr/GrCCCoverageProcessor.cpp
index 1d570dca06..10b6736f33 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor.cpp
+++ b/src/gpu/ccpr/GrCCCoverageProcessor.cpp
@@ -23,12 +23,6 @@ void GrCCCoverageProcessor::Shader::emitFragmentCode(const GrCCCoverageProcessor
     this->onEmitFragmentCode(f, "coverage");
     f->codeAppendf("%s.a = coverage;", skOutputColor);
     f->codeAppendf("%s = half4(1);", skOutputCoverage);
-#ifdef SK_DEBUG
-    if (proc.debugVisualizationsEnabled()) {
-        f->codeAppendf("%s = half4(-%s.a, %s.a, 0, abs(%s.a));",
-                       skOutputColor, skOutputColor, skOutputColor, skOutputColor);
-    }
-#endif
 }
 
 void GrCCCoverageProcessor::Shader::EmitEdgeDistanceEquation(GrGLSLVertexGeoBuilder* s,
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor.h b/src/gpu/ccpr/GrCCCoverageProcessor.h
index a60a38ee5e..d826b810c9 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor.h
+++ b/src/gpu/ccpr/GrCCCoverageProcessor.h
@@ -104,11 +104,10 @@ public:
     GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override;
 
 #ifdef SK_DEBUG
-    // Increases the 1/2 pixel AA bloat by a factor of debugBloat and outputs color instead of
-    // coverage (coverage=+1 -> green, coverage=0 -> black, coverage=-1 -> red).
-    void enableDebugVisualizations(float debugBloat) { fDebugBloat = debugBloat; }
-    bool debugVisualizationsEnabled() const { return fDebugBloat > 0; }
-    float debugBloat() const { SkASSERT(this->debugVisualizationsEnabled()); return fDebugBloat; }
+    // Increases the 1/2 pixel AA bloat by a factor of debugBloat.
+    void enableDebugBloat(float debugBloat) { fDebugBloat = debugBloat; }
+    bool debugBloatEnabled() const { return fDebugBloat > 0; }
+    float debugBloat() const { SkASSERT(this->debugBloatEnabled()); return fDebugBloat; }
 #endif
 
     // Appends a GrMesh that will draw the provided instances. The instanceBuffer must be an array
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp b/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp
index dd3d4890e1..82a292cb06 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp
+++ b/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp
@@ -95,7 +95,7 @@ protected:
 
         float bloat = kAABloatRadius;
 #ifdef SK_DEBUG
-        if (proc.debugVisualizationsEnabled()) {
+        if (proc.debugBloatEnabled()) {
             bloat *= proc.debugBloat();
         }
 #endif
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp b/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp
index 9fbac5a64f..e0ec4d4142 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp
+++ b/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp
@@ -62,7 +62,7 @@ protected:
 
         float bloat = kAABloatRadius;
 #ifdef SK_DEBUG
-        if (proc.debugVisualizationsEnabled()) {
+        if (proc.debugBloatEnabled()) {
             bloat *= proc.debugBloat();
         }
 #endif