Added API for Bevel NormalSource.

gm/lightingshaderbevel.cpp

Index: gm/lightingshaderbevel.cpp
diff --git a/gm/lightingshaderbevel.cpp b/gm/lightingshaderbevel.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..c0c5377296f31a703a04c61cdf35a8b02b9de2a9
--- /dev/null
+++ b/gm/lightingshaderbevel.cpp
@@ -0,0 +1,157 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+
+#include "SkBitmapProcShader.h"
+#include "SkLightingShader.h"
+#include "SkNormalSource.h"
+#include "SkPoint3.h"
+#include "SkShader.h"
+
+
+namespace skiagm {
+
+// This GM exercises lighting shaders when used with bevel SkNormalSource objects.
+class LightingShaderBevelGM : public GM {
+public:
+    LightingShaderBevelGM() {
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
+    }
+
+protected:
+    SkString onShortName() override {
+        return SkString("lightingshaderbevel");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(550, 420);
+    }
+
+    void onOnceBeforeDraw() override {
+        SkLights::Builder builder;
+        const SkVector3 kLightFromUpperRight = SkVector3::Make(0.788f, 0.394f, 0.473f);
+
+        builder.add(SkLights::Light(SkColor3f::Make(1.0f, 1.0f, 1.0f),
+                                    kLightFromUpperRight));
+        builder.add(SkLights::Light(SkColor3f::Make(0.2f, 0.2f, 0.2f)));
+        fLights = builder.finish();
+
+        fRect = SkRect::MakeIWH(kTexSize, kTexSize);
+        SkMatrix matrix;
+        SkRect bitmapBounds = SkRect::MakeIWH(kTexSize, kTexSize);
+        matrix.setRectToRect(bitmapBounds, fRect, SkMatrix::kFill_ScaleToFit);
+
+        SkBitmap diffuseMap = sk_tool_utils::create_checkerboard_bitmap(
+                kTexSize, kTexSize,
+                sk_tool_utils::color_to_565(0x0),
+                sk_tool_utils::color_to_565(0xFF804020),
+                8);
+        fDiffuse = SkMakeBitmapShader(diffuseMap, SkShader::kClamp_TileMode,
+                                      SkShader::kClamp_TileMode, &matrix, nullptr);
+    }
+
+    // Scales shape around origin, rotates shape around origin, then translates shape to origin
+    void positionCTM(SkCanvas *canvas, SkScalar scaleX, SkScalar scaleY, SkScalar rotate) const {
+        canvas->translate(kTexSize/2.0f, kTexSize/2.0f);
+        canvas->scale(scaleX, scaleY);
+        canvas->rotate(rotate);
+        canvas->translate(-kTexSize/2.0f, -kTexSize/2.0f);
+    }
+
+    static constexpr int NUM_BOOLEAN_PARAMS = 2;
+    void drawRect(SkCanvas* canvas, SkScalar scaleX, SkScalar scaleY, SkScalar rotate,
+                  SkNormalSource::BevelType bevelType, bool useTranslucentPaint,
+                  bool useNegativeHeight) {
+        canvas->save();
+
+        this->positionCTM(canvas, scaleX, scaleY, rotate);
+
+        SkPaint paint;
+
+        int width = 10.0f;
+        int height = useNegativeHeight ? -7.0f : 7.0f;
+        sk_sp<SkNormalSource> normalSource = SkNormalSource::MakeBevel(bevelType, width, height);
+
+        if (useTranslucentPaint) {
+            paint.setAlpha(0x99);
+        }
+
+        paint.setShader(SkLightingShader::Make(fDiffuse, std::move(normalSource), fLights));
+        canvas->drawRect(fRect, paint);
+
+        canvas->restore();
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+
+        constexpr SkScalar LABEL_SIZE = 10.0f;
+        SkPaint labelPaint;
+        labelPaint.setTypeface(sk_tool_utils::create_portable_typeface("sans-serif",
+                                                                       SkFontStyle()));
+        labelPaint.setAntiAlias(true);
+        labelPaint.setTextSize(LABEL_SIZE);
+
+        constexpr int GRID_COLUMN_NUM = 4;
+        constexpr SkScalar GRID_CELL_WIDTH = kTexSize + 20.0f + NUM_BOOLEAN_PARAMS * LABEL_SIZE;
+
+        int gridNum = 0;
+
+        // Running through all possible parameter combinations
+        for (auto bevelType : {SkNormalSource::BevelType::kLinear,
+                               SkNormalSource::BevelType::kRoundedIn,
+                               SkNormalSource::BevelType::kRoundedOut}) {
+            for (bool useTranslucentPaint : {true, false}) {

[egdaniel, 2016/07/26 19:54:41]

Is there anything special with the bevel shader when using a translucent paint?
Maybe this should just be left for the other lightshader gm you made.

I would add something to test rotated geometries and different geometries
(circles, rects, round rects, some convex patch, some concave path).

[dvonbeck, 2016/07/27 17:44:57]

At the time I was thinking the normal could get premul'd but now I realize
that's not true. I took it out.

+                for (bool useNegativeHeight : {true, false}) {
+
+                    // Determining position
+                    SkScalar xPos = (gridNum % GRID_COLUMN_NUM) * GRID_CELL_WIDTH;
+                    SkScalar yPos = (gridNum / GRID_COLUMN_NUM) * GRID_CELL_WIDTH;
+
+                    canvas->save();
+
+                    canvas->translate(xPos, yPos);
+                    this->drawRect(canvas, 1.0f, 1.0f, 0.f, bevelType, useTranslucentPaint,
+                                   useNegativeHeight);
+                    // Drawing labels
+                    canvas->translate(0.0f, SkIntToScalar(kTexSize));
+                    {
+                        canvas->translate(0.0f, LABEL_SIZE);
+                        SkString label;
+                        label.appendf("useTranslucentPaint: %d", useTranslucentPaint);
+                        canvas->drawText(label.c_str(), label.size(), 0.0f, 0.0f, labelPaint);
+                    }
+                    {
+                        canvas->translate(0.0f, LABEL_SIZE);
+                        SkString label;
+                        label.appendf("useNegativeHeight: %d", useNegativeHeight);
+                        canvas->drawText(label.c_str(), label.size(), 0.0f, 0.0f, labelPaint);
+                    }
+
+                    canvas->restore();
+
+                    gridNum++;
+                }
+            }
+        }
+    }
+
+private:
+    static const int kTexSize = 96;
+
+    sk_sp<SkShader> fDiffuse;
+
+    SkRect fRect;
+    sk_sp<SkLights> fLights;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM(return new LightingShaderBevelGM;)
+}