First pass at Rect Effect

src/gpu/GrAARectRenderer.cpp

Index: src/gpu/GrAARectRenderer.cpp
===================================================================
--- src/gpu/GrAARectRenderer.cpp	(revision 8539)
+++ src/gpu/GrAARectRenderer.cpp	(working copy)
@@ -8,6 +8,7 @@
 #include "GrAARectRenderer.h"
 #include "GrRefCnt.h"
 #include "GrGpu.h"
+#include "effects/GrRectEffect.h"
 
 SK_DEFINE_INST_COUNT(GrAARectRenderer)
 
@@ -181,6 +182,92 @@
     target->resetIndexSource();
 }
 
+struct RectVertex {
+    GrPoint fPos;
+    GrPoint fCenter;
+    GrPoint fDir;
+    GrPoint fWidthHeight;
+};
+
+
+void GrAARectRenderer::shaderFillAARect(GrGpu* gpu,
+                                        GrDrawTarget* target,
+                                        const GrRect& rect,
+                                        const SkMatrix& combinedMatrix,
+                                        const GrRect& devRect,
+                                        bool useVertexCoverage) {
+    GrDrawState* drawState = target->drawState();
+
+    SkPoint center = SkPoint::Make(rect.centerX(), rect.centerY());
+    combinedMatrix.mapPoints(&center, 1);
+
+    // compute transformed (0, 1) vector
+    SkVector dir = { combinedMatrix[SkMatrix::kMSkewX], combinedMatrix[SkMatrix::kMScaleY] };
+    dir.normalize();
+
+    // compute transformed (width, 0) and (0, height) vectors
+    SkVector vec[2] = {
+      { combinedMatrix[SkMatrix::kMScaleX] * rect.width(), 
+	combinedMatrix[SkMatrix::kMSkewY] * rect.width() },
+      { combinedMatrix[SkMatrix::kMSkewX] * rect.height(), 
+	combinedMatrix[SkMatrix::kMScaleY] * rect.height() }
+    };
+
+    SkScalar newWidth = vec[0].length() / 2.0f + 0.5f;
+    SkScalar newHeight = vec[1].length() / 2.0f + 0.5f;
+
+    static const GrVertexAttrib kVertexAttribs[] = {
+        { kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding },
+        { kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding },
+        { kVec2f_GrVertexAttribType, 3*sizeof(GrPoint), kEffect_GrVertexAttribBinding }
+    };
+    drawState->setVertexAttribs(kVertexAttribs, SK_ARRAY_COUNT(kVertexAttribs));
+    GrAssert(sizeof(RectVertex) == drawState->getVertexSize());
+
+    GrDrawTarget::AutoReleaseGeometry geo(target, 4, 0);
+    if (!geo.succeeded()) {
+        GrPrintf("Failed to get space for vertices!\n");
+        return;
+    }
+
+    RectVertex* verts = reinterpret_cast<RectVertex*>(geo.vertices());
+
+    enum {
+        // the edge effects share this stage with glyph rendering
+        // (kGlyphMaskStage in GrTextContext) && SW path rendering
+        // (kPathMaskStage in GrSWMaskHelper)
+        kEdgeEffectStage = GrPaint::kTotalStages,
+    };
+
+    GrEffectRef* effect = GrRectEffect::Create();
+    static const int kRectAttrIndex = 1;
+    static const int kWidthIndex = 2;
+    drawState->setEffect(kEdgeEffectStage, effect, kRectAttrIndex, kWidthIndex)->unref();
+
+    for (int i = 0; i < 4; ++i) {
+        verts[i].fCenter = center;
+        verts[i].fDir = dir;
+        verts[i].fWidthHeight.fX = newWidth;
+        verts[i].fWidthHeight.fY = newHeight;
+    }
+
+    SkRect devBounds = {
+        devRect.fLeft   - SK_ScalarHalf,
+        devRect.fTop    - SK_ScalarHalf,
+        devRect.fRight  + SK_ScalarHalf,
+        devRect.fBottom + SK_ScalarHalf
+    };
+
+    verts[0].fPos = SkPoint::Make(devBounds.fLeft, devBounds.fTop);
+    verts[1].fPos = SkPoint::Make(devBounds.fLeft, devBounds.fBottom);
+    verts[2].fPos = SkPoint::Make(devBounds.fRight, devBounds.fBottom);
+    verts[3].fPos = SkPoint::Make(devBounds.fRight, devBounds.fTop);
+
+    target->setIndexSourceToBuffer(gpu->getContext()->getQuadIndexBuffer());
+    target->drawIndexedInstances(kTriangles_GrPrimitiveType, 1, 4, 6);
+    target->resetIndexSource();
+}
+
 void GrAARectRenderer::strokeAARect(GrGpu* gpu,
                                     GrDrawTarget* target,
                                     const GrRect& devRect,