SkLS accepts nullptr for pointer args, handles alpha accurately, has new GM

gm/lightingshader2.cpp

Index: gm/lightingshader2.cpp
diff --git a/gm/lightingshader2.cpp b/gm/lightingshader2.cpp
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index 0000000000000000000000000000000000000000..c2f4d6caaca04cfd94d4037fd0ed5076e0cb6dc5
--- /dev/null
+++ b/gm/lightingshader2.cpp
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+/*
+ * 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"
+
+// Create a truncated pyramid normal map
+static SkBitmap make_frustum_normalmap(int texSize) {
+    SkBitmap frustum;
+    frustum.allocN32Pixels(texSize, texSize);
+
+    sk_tool_utils::create_frustum_normal_map(&frustum, SkIRect::MakeWH(texSize, texSize));
+    return frustum;
+}
+
+namespace skiagm {
+
+// This GM exercises lighting shaders. Specifically, nullptr arguments, scaling when using
+// normal maps, and paint transparency.
+class LightingShader2GM : public GM {
+public:
+    LightingShader2GM() {
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
+    }
+
+protected:
+    SkString onShortName() override {
+        return SkString("lightingshader2");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kGMSize, kGMSize);
+    }
+
+    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 opaqueDiffuseMap = sk_tool_utils::create_checkerboard_bitmap(
+                kTexSize, kTexSize,
+                sk_tool_utils::color_to_565(0x0),
+                sk_tool_utils::color_to_565(0xFF804020),
+                8);
+        fOpaqueDiffuse = SkMakeBitmapShader(opaqueDiffuseMap, SkShader::kClamp_TileMode,
+                                            SkShader::kClamp_TileMode, &matrix, nullptr);
+
+        SkBitmap translucentDiffuseMap = sk_tool_utils::create_checkerboard_bitmap(
+                kTexSize, kTexSize,
+                SkColorSetARGB(0x55, 0x00, 0x00, 0x00),
+                SkColorSetARGB(0x55, 0x80, 0x40, 0x20),
+                8);
+        fTranslucentDiffuse = SkMakeBitmapShader(translucentDiffuseMap, SkShader::kClamp_TileMode,
+                                                 SkShader::kClamp_TileMode, &matrix, nullptr);
+
+        SkBitmap normalMap = make_frustum_normalmap(kTexSize);
+        fNormalMapShader = SkMakeBitmapShader(normalMap, 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 = 4;
+    void drawRect(SkCanvas* canvas, SkScalar scaleX, SkScalar scaleY,
+                  SkScalar rotate, bool useNormalSource, bool useDiffuseShader,
+                  bool useTranslucentPaint, bool useTranslucentShader) {
+        canvas->save();
+
+        this->positionCTM(canvas, scaleX, scaleY, rotate);
+
+        const SkMatrix& ctm = canvas->getTotalMatrix();
+
+        SkPaint paint;
+        sk_sp<SkNormalSource> normalSource = nullptr;
+        sk_sp<SkShader> diffuseShader = nullptr;
+
+        if (useNormalSource) {
+            normalSource = SkNormalSource::MakeFromNormalMap(fNormalMapShader, ctm);
+        }
+
+        if (useDiffuseShader) {
+            diffuseShader = (useTranslucentShader) ? fTranslucentDiffuse : fOpaqueDiffuse;
+        } else {
+            paint.setColor(0xFF00FF00);
+        }
+
+        if (useTranslucentPaint) {
+            paint.setAlpha(0x99);
+        }
+
+        paint.setShader(SkLightingShader::Make(std::move(diffuseShader), 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 bool parameter combinations
+        for (bool useNormalSource : {true, false}) {
+            for (bool useDiffuseShader : {true, false}) {
+                for (bool useTranslucentPaint : {true, false}) {
+                    for (bool useTranslucentShader : {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, useNormalSource, useDiffuseShader,
+                                       useTranslucentPaint, useTranslucentShader);
+                        // Drawing labels
+                        canvas->translate(0.0f, SkIntToScalar(kTexSize));
+                        {
+                            canvas->translate(0.0f, LABEL_SIZE);
+                            SkString label;
+                            label.appendf("useNormalSource: %d", useNormalSource);
+                            canvas->drawText(label.c_str(), label.size(), 0.0f, 0.0f, labelPaint);
+                        }
+                        {
+                            canvas->translate(0.0f, LABEL_SIZE);
+                            SkString label;
+                            label.appendf("useDiffuseShader: %d", useDiffuseShader);
+                            canvas->drawText(label.c_str(), label.size(), 0.0f, 0.0f, labelPaint);
+                        }
+                        {
+                            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("useTranslucentShader: %d", useTranslucentShader);
+                            canvas->drawText(label.c_str(), label.size(), 0.0f, 0.0f, labelPaint);
+                        }
+
+                        canvas->restore();
+
+                        gridNum++;
+                    }
+                }
+            }
+        }
+
+
+        // Rotation/scale test
+        {
+            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, 0.6f, 0.6f, 45.0f, true, true, true, true);
+            canvas->restore();
+
+            gridNum++;
+        }
+
+        // Anisotropic scale test
+        {
+            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, 0.6f, 0.4f, 30.0f, true, true, true, true);
+            canvas->restore();
+
+            gridNum++;
+        }
+    }
+
+private:
+    static const int kTexSize = 96;
+    static const int kGMSize  = 512;
+
+    sk_sp<SkShader> fOpaqueDiffuse;
+    sk_sp<SkShader> fTranslucentDiffuse;
+    sk_sp<SkShader> fNormalMapShader;
+
+    SkRect fRect;
+    sk_sp<SkLights> fLights;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM(return new LightingShader2GM;)
+}