Add Loop Blinn hairline conics to GPU

samplecode/SampleHairCurves.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SampleCode.h"
 #include "SkView.h"
 #include "SkCanvas.h"
@@ skipping 17 matching lines @@
 
 
     virtual void onDrawContent(SkCanvas* canvas) {
         SkPaint paint;
         paint.setAntiAlias(true);
         paint.setStyle(SkPaint::kStroke_Style);
         paint.setStrokeWidth(0);
         canvas->save();
         canvas->scale(1000 * SK_Scalar1, 1000 * SK_Scalar1);
         SkRandom rand;
+        SkRandom randW;
         SkPath curves;
         SkPath hulls;
         SkPath ctrlPts;
         for (int i = 0; i < 100; ++i) {
             SkScalar pts[] = {
                 rand.nextUScalar1(), rand.nextUScalar1(),
                 rand.nextUScalar1(), rand.nextUScalar1(),
                 rand.nextUScalar1(), rand.nextUScalar1(),
                 rand.nextUScalar1(), rand.nextUScalar1()
             };
@@ skipping 27 matching lines @@
             hulls.lineTo(pts[4], pts[5]);
 
             ctrlPts.addCircle(pts[0], pts[1], SK_Scalar1 / 200);
             ctrlPts.addCircle(pts[2], pts[3], SK_Scalar1 / 200);
             ctrlPts.addCircle(pts[4], pts[5], SK_Scalar1 / 200);
         }
         for (int i = 0; i < 100; ++i) {
             SkScalar pts[] = {
                 rand.nextUScalar1(), rand.nextUScalar1(),
                 rand.nextUScalar1(), rand.nextUScalar1(),
+                rand.nextUScalar1(), rand.nextUScalar1(),
+            };
+            SkScalar weight = randW.nextUScalar1() * 2.0f;
+
+            curves.moveTo(pts[0], pts[1]);
+            curves.conicTo(pts[2], pts[3],
+                          pts[4], pts[5],
+                          weight);
+
+            hulls.moveTo(pts[0], pts[1]);
+            hulls.lineTo(pts[2], pts[3]);
+            hulls.lineTo(pts[4], pts[5]);
+
+            ctrlPts.addCircle(pts[0], pts[1], SK_Scalar1 / 200);
+            ctrlPts.addCircle(pts[2], pts[3], SK_Scalar1 / 200);
+            ctrlPts.addCircle(pts[4], pts[5], SK_Scalar1 / 200);
+        }
+        for (int i = 0; i < 100; ++i) {
+            SkScalar pts[] = {
+                rand.nextUScalar1(), rand.nextUScalar1(),
+                rand.nextUScalar1(), rand.nextUScalar1(),
             };
             curves.moveTo(pts[0], pts[1]);
             curves.lineTo(pts[2], pts[3]);
 
             ctrlPts.addCircle(pts[0], pts[1], SK_Scalar1 / 200);
             ctrlPts.addCircle(pts[2], pts[3], SK_Scalar1 / 200);
         }
 
         paint.setColor(SK_ColorBLACK);
         canvas->drawPath(curves, paint);
         paint.setColor(SK_ColorRED);
         //canvas->drawPath(hulls, paint);
         paint.setStyle(SkPaint::kFill_Style);
         paint.setColor(SK_ColorBLUE);
         //canvas->drawPath(ctrlPts, paint);
 
         canvas->restore();
     }
 
 private:
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static SkView* MyFactory() { return new HairCurvesView; }
 static SkViewRegister reg(MyFactory);