added stroking support to GrAALinearizingConvexPathRenderer

src/gpu/GrAALinearizingConvexPathRenderer.cpp

Index: src/gpu/GrAALinearizingConvexPathRenderer.cpp
diff --git a/src/gpu/GrAALinearizingConvexPathRenderer.cpp b/src/gpu/GrAALinearizingConvexPathRenderer.cpp
index e03df81def198f76d4bdc09349f726cc7cf4537e..6e672693b369667263f7a0353c8f6c4309a033e8 100644
--- a/src/gpu/GrAALinearizingConvexPathRenderer.cpp
+++ b/src/gpu/GrAALinearizingConvexPathRenderer.cpp
@@ -23,12 +23,17 @@
 #include "SkGeometry.h"
 #include "SkString.h"
 #include "SkTraceEvent.h"
+#include "SkPathPriv.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/GrGLSL.h"
 #include "gl/GrGLGeometryProcessor.h"
 #include "gl/builders/GrGLProgramBuilder.h"
 

[robertphillips, 2015/06/16 13:13:02]

More informative name? Which buffer ?

-#define DEFAULT_BUFFER_SIZE 100
+static const int DEFAULT_BUFFER_SIZE = 100;
+
+// The thicker the stroke, the harder it is to produce high-quality results using tessellation. For
+// the time being, we simply drop back to software rendering above this stroke width.
+static const SkScalar kMaxStrokeWidth = 20.0;
 
 GrAALinearizingConvexPathRenderer::GrAALinearizingConvexPathRenderer() {
 }
@@ -41,7 +46,21 @@ bool GrAALinearizingConvexPathRenderer::canDrawPath(const GrDrawTarget* target,
                                                     const SkPath& path,
                                                     const GrStrokeInfo& stroke,
                                                     bool antiAlias) const {
-    return (antiAlias && stroke.isFillStyle() && !path.isInverseFillType() && path.isConvex());
+    if (!antiAlias) {
+        return false;
+    }
+    if (path.isInverseFillType()) {
+        return false;
+    }
+    if (!path.isConvex()) {
+        return false;
+    }
+    if (stroke.getStyle() == SkStrokeRec::kStroke_Style) {
+        return viewMatrix.isSimilarity() && stroke.getWidth() <= kMaxStrokeWidth && 
+                !stroke.isDashed() && SkPathPriv::LastVerbIsClose(path) &&
+                stroke.getJoin() != SkPaint::Join::kRound_Join;
+    }
+    return stroke.getStyle() == SkStrokeRec::kFill_Style;
 }
 
 // extract the result vertices and indices from the GrAAConvexTessellator
@@ -61,16 +80,15 @@ static void extract_verts(const GrAAConvexTessellator& tess,
     // Make 'verts' point to the colors
     verts += sizeof(SkPoint);
     for (int i = 0; i < tess.numPts(); ++i) {
-        SkASSERT(tess.depth(i) >= -0.5f && tess.depth(i) <= 0.5f);
         if (tweakAlphaForCoverage) {
-            SkASSERT(SkScalarRoundToInt(255.0f * (tess.depth(i) + 0.5f)) <= 255);
-            unsigned scale = SkScalarRoundToInt(255.0f * (tess.depth(i) + 0.5f));
+            SkASSERT(SkScalarRoundToInt(255.0f * tess.coverage(i)) <= 255);
+            unsigned scale = SkScalarRoundToInt(255.0f * tess.coverage(i));
             GrColor scaledColor = (0xff == scale) ? color : SkAlphaMulQ(color, scale);
             *reinterpret_cast<GrColor*>(verts + i * vertexStride) = scaledColor;
         } else {
             *reinterpret_cast<GrColor*>(verts + i * vertexStride) = color;
             *reinterpret_cast<float*>(verts + i * vertexStride + sizeof(GrColor)) = 
-                                                                    tess.depth(i) + 0.5f;
+                    tess.coverage(i);
         }
     }
 
@@ -98,6 +116,9 @@ public:
         GrColor fColor;
         SkMatrix fViewMatrix;
         SkPath fPath;
+        SkScalar fStrokeWidth;
+        SkPaint::Join fJoin;
+        SkScalar fMiterLimit;
     };
 
     static GrBatch* Create(const Geometry& geometry) {
@@ -159,7 +180,7 @@ public:
                 firstIndex, vertexCount, indexCount);
         batchTarget->draw(info);
     }
-
+    
     void generateGeometry(GrBatchTarget* batchTarget, const GrPipeline* pipeline) override {
         bool canTweakAlphaForCoverage = this->canTweakAlphaForCoverage();
 
@@ -183,8 +204,6 @@ public:
                  vertexStride == sizeof(GrDefaultGeoProcFactory::PositionColorAttr) :
                  vertexStride == sizeof(GrDefaultGeoProcFactory::PositionColorCoverageAttr));
 
-        GrAAConvexTessellator tess;
-
         int instanceCount = fGeoData.count();
 
         int vertexCount = 0;
@@ -194,9 +213,8 @@ public:
         uint8_t* vertices = (uint8_t*) malloc(maxVertices * vertexStride);
         uint16_t* indices = (uint16_t*) malloc(maxIndices * sizeof(uint16_t));
         for (int i = 0; i < instanceCount; i++) {
-            tess.rewind();
-
             Geometry& args = fGeoData[i];
+            GrAAConvexTessellator tess(args.fStrokeWidth, args.fJoin, args.fMiterLimit);
 
             if (!tess.tessellate(args.fViewMatrix, args.fPath)) {
                 continue;
@@ -288,7 +306,7 @@ bool GrAALinearizingConvexPathRenderer::onDrawPath(GrDrawTarget* target,
                                                    GrColor color,
                                                    const SkMatrix& vm,
                                                    const SkPath& path,
-                                                   const GrStrokeInfo&,
+                                                   const GrStrokeInfo& stroke,
                                                    bool antiAlias) {
     if (path.isEmpty()) {
         return true;
@@ -297,6 +315,9 @@ bool GrAALinearizingConvexPathRenderer::onDrawPath(GrDrawTarget* target,
     geometry.fColor = color;
     geometry.fViewMatrix = vm;
     geometry.fPath = path;
+    geometry.fStrokeWidth = stroke.isFillStyle() ? -1.0f : stroke.getWidth();
+    geometry.fJoin = stroke.isFillStyle() ? SkPaint::Join::kMiter_Join : stroke.getJoin();
+    geometry.fMiterLimit = stroke.getMiter();
 
     SkAutoTUnref<GrBatch> batch(AAFlatteningConvexPathBatch::Create(geometry));
     target->drawBatch(pipelineBuilder, batch);