Create new target to hold gpu test code, enable direct testing of GrEffects in GM.

gm/beziereffects.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.
+ */
+
+// This test only works with the GPU backend.
+
+#include "gm.h"
+
+#if SK_SUPPORT_GPU && 0 // Can be enabled when cubic effect is checked in.
+
+#include "GrContext.h"
+#include "GrPathUtils.h"
+#include "GrTest.h"
+#include "SkColorPriv.h"
+#include "SkDevice.h"
+

[robertphillips, 2013/08/20 16:47:34]

// Position & KLM coefficient. These are the vertex attributes for Bezier
curves. The last value of the Vec4f is ignored.

[bsalomon, 2013/08/21 14:16:03]

Done.

+extern const GrVertexAttrib kAttribs[] = {
+    {kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
+    {kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding}
+};
+
+static inline SkScalar eval_line(const SkPoint& p, const SkScalar lineEq[3], SkScalar sign) {
+    return sign * (lineEq[0] * p.fX + lineEq[1] * p.fY + lineEq[2]);
+}
+

[robertphillips, 2013/08/20 16:47:34]

Should the namespace also enclose kAttribs & eval_line?

[bsalomon, 2013/08/21 14:16:03]

I don't think so.

+namespace skiagm {
+

[robertphillips, 2013/08/20 16:47:34]

// This GM ...

[bsalomon, 2013/08/21 14:16:03]

Done.

+class BezierEffects : public GM {
+public:
+    BezierEffects() {
+        this->setBGColor(0xFFFFFFFF);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("bezier_effects");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return make_isize(800, 800);
+    }
+
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        // This is a GPU-specific GM.
+        return kGPUOnly_Flag;
+    }
+
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        SkDevice* device = canvas->getTopDevice();
+        GrRenderTarget* rt = device->accessRenderTarget();
+        if (NULL == rt) {
+            return;
+        }
+        GrContext* context = rt->getContext();
+        if (NULL == context) {
+            return;
+        }
+
+        struct Vertex {
+            SkPoint fPosition;
+            float   fKLM[4]; // The last value is ignored. The effect expects a vec4f.
+        };
+
+        static const int kNumCubics = 10;
+        SkMWCRandom rand;
+
+        int numCols = SkScalarCeilToInt(SkScalarSqrt(SkIntToScalar(kNumCubics)));
+        int numRows = SkScalarCeilToInt(SkIntToScalar(kNumCubics) / numCols);
+        SkScalar w = SkIntToScalar(rt->width()) / numCols;
+        SkScalar h = SkIntToScalar(rt->height()) / numRows;
+        int row = 0;
+        int col = 0;
+
+        for (int i = 0; i < kNumCubics; ++i) {
+            SkScalar x = SkScalarMul(col, w);
+            SkScalar y = SkScalarMul(row, h);
+            SkPoint controlPts[] = {
+                {x + rand.nextRangeF(0, w), y + rand.nextRangeF(0, h)},
+                {x + rand.nextRangeF(0, w), y + rand.nextRangeF(0, h)},
+                {x + rand.nextRangeF(0, w), y + rand.nextRangeF(0, h)},
+                {x + rand.nextRangeF(0, w), y + rand.nextRangeF(0, h)}
+            };
+            SkPoint chopped[10];
+            SkScalar klmEqs[9];
+            SkScalar klmSigns[3];
+            int cnt = GrPathUtils::chopCubicAtLoopIntersection(controlPts,
+                                                               chopped,
+                                                               klmEqs,
+                                                               klmSigns,
+                                                               controlPts);
+
+            SkPaint ctrlPtPaint;
+            ctrlPtPaint.setColor(rand.nextU() | 0xFF000000);
+            for (int i = 0; i < 4; ++i) {
+                canvas->drawCircle(controlPts[i].fX, controlPts[i].fY, 6.f, ctrlPtPaint);
+            }
+
+            SkPaint polyPaint;
+            polyPaint.setColor(0xffA0A0A0);
+            polyPaint.setStrokeWidth(0);
+            polyPaint.setStyle(SkPaint::kStroke_Style);
+            canvas->drawPoints(SkCanvas::kPolygon_PointMode, 4, controlPts, polyPaint);
+
+            SkPaint choppedPtPaint;
+            choppedPtPaint.setColor(~ctrlPtPaint.getColor() | 0xFF000000);
+
+            for (int c = 0; c < cnt; ++c) {
+                SkPoint* pts = chopped + 3 * c;
+
+                for (int i = 0; i < 4; ++i) {
+                    canvas->drawCircle(pts[i].fX, pts[i].fY, 3.f, choppedPtPaint);
+                }
+
+                Vertex verts[4];
+                SkRect bounds;
+                bounds.set(pts, 4);

[robertphillips, 2013/08/20 16:47:34]

Doesn't set do all of the following 8 lines?

[bsalomon, 2013/08/21 14:16:03]

oops.. yes... this creeped in when Greg and I were debugging something.

+                bounds.fLeft = bounds.fRight = pts[0].fX;
+                bounds.fTop = bounds.fBottom = pts[0].fY;
+                for (int i = 1; i < 4; ++i) {
+                    bounds.fLeft = SkTMin(bounds.fLeft, pts[i].fX);
+                    bounds.fRight = SkTMax(bounds.fRight, pts[i].fX);
+                    bounds.fTop = SkTMin(bounds.fTop, pts[i].fY);
+                    bounds.fBottom = SkTMax(bounds.fBottom, pts[i].fY);
+                };
+
+                SkPaint boundsPaint;
+                boundsPaint.setColor(0xff808080);
+                boundsPaint.setStrokeWidth(0);
+                boundsPaint.setStyle(SkPaint::kStroke_Style);
+                canvas->drawRect(bounds, boundsPaint);
+

[robertphillips, 2013/08/20 16:47:34]

Move "Vertex verts[4];" down here?

[bsalomon, 2013/08/21 14:16:03]

Done.

+                verts[0].fPosition.setRectFan(bounds.fLeft, bounds.fTop,
+                                              bounds.fRight, bounds.fBottom,
+                                              sizeof(Vertex));
+                for (int v = 0; v < 4; ++v) {
+                    verts[v].fKLM[0] = eval_line(verts[v].fPosition, klmEqs + 0, klmSigns[c]);
+                    verts[v].fKLM[1] = eval_line(verts[v].fPosition, klmEqs + 3, klmSigns[c]);
+                    verts[v].fKLM[2] = eval_line(verts[v].fPosition, klmEqs + 6, 1.f);
+                }
+
+                GrTestTarget tt;
+                context->getTestTarget(&tt);
+                if (NULL == tt.target()) {
+                    continue;
+                }
+                GrDrawState* drawState = tt.target()->drawState();
+                drawState->setVertexAttribs<kAttribs>(2);
+                SkAutoTUnref<GrEffectRef> effect(HairCubicEdgeEffect::Create());
+                if (!effect) {
+                    continue;
+                }
+                drawState->addCoverageEffect(effect, 1);
+                drawState->setRenderTarget(rt);
+                drawState->setColor(0xff000000);
+
+                tt.target()->setVertexSourceToArray(verts, 4);
+                tt.target()->setIndexSourceToBuffer(context->getQuadIndexBuffer());
+                tt.target()->drawIndexed(kTriangleFan_GrPrimitiveType, 0, 0, 4, 6);
+            }
+            ++col;
+            if (numCols == col) {
+                col = 0;
+                ++row;
+            }
+        }
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(BezierEffects); )
+
+}
+
+#endif