LightingFP now supports multiple directional lights

gm/lightingshader2.cpp

 /*
  * 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 "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.
+// normal maps, paint transparency, zero directional lights, multiple directional lights.
 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(600, 740);
     }
 
     void onOnceBeforeDraw() override {
+        const SkVector3 kLightFromUpperRight = SkVector3::Make(0.788f, 0.394f, 0.473f);
+        const SkVector3 kLightFromUpperLeft = SkVector3::Make(-0.788f, 0.394f, 0.473f);
+
+        // Standard set of lights
         SkLights::Builder builder;
-        const SkVector3 kLightFromUpperRight = SkVector3::Make(0.788f, 0.394f, 0.473f);
-
         builder.add(SkLights::Light::MakeDirectional(SkColor3f::Make(1.0f, 1.0f, 1.0f),
                                                      kLightFromUpperRight));
         builder.add(SkLights::Light::MakeAmbient(SkColor3f::Make(0.2f, 0.2f, 0.2f)));
         fLights = builder.finish();
 
+        // No directional lights
+        SkLights::Builder builderNoDir;
+        builderNoDir.add(SkLights::Light::MakeAmbient(SkColor3f::Make(0.2f, 0.2f, 0.2f)));
+        fLightsNoDir = builderNoDir.finish();
+
+        // Two directional lights
+        SkLights::Builder builderTwoDir;
+        builderTwoDir.add(SkLights::Light::MakeDirectional(SkColor3f::Make(1.0f, 0.0f, 1.0f),
+                                                           kLightFromUpperRight));
+        builderTwoDir.add(SkLights::Light::MakeDirectional(SkColor3f::Make(0.0f, 1.0f, 1.0f),
+                                                           kLightFromUpperLeft));
+        builderTwoDir.add(SkLights::Light::MakeAmbient(SkColor3f::Make(0.2f, 0.2f, 0.2f)));
+        fLightsTwoDir = builderTwoDir.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);
@@ skipping 19 matching lines @@
     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) {
+                  bool useTranslucentPaint, bool useTranslucentShader, sk_sp<SkLights> lights) {
         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));
+                                               std::move(lights)));
         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",
@@ skipping 13 matching lines @@
                     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);
+                                       useTranslucentPaint, useTranslucentShader, fLights);
                         // 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);
@@ skipping 23 matching lines @@
         }
 
 
         // 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);
+            this->drawRect(canvas, 0.6f, 0.6f, 45.0f, true, true, true, true, fLights);
             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);
+            this->drawRect(canvas, 0.6f, 0.4f, 30.0f, true, true, true, true, fLights);
             canvas->restore();
 
             gridNum++;
+        }
+
+        // No directional lights 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, 1.0f, 1.0f, 0.0f, true, true, false, false, fLightsNoDir);
+            canvas->restore();
+
+            gridNum++;
+        }
+
+        // Two directional lights 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, 1.0f, 1.0f, 0.0f, true, true, false, false, fLightsTwoDir);
+            canvas->restore();
+
+            gridNum++;
         }
     }
 
 private:
     static const int kTexSize = 96;
 
     sk_sp<SkShader> fOpaqueDiffuse;
     sk_sp<SkShader> fTranslucentDiffuse;
     sk_sp<SkShader> fNormalMapShader;
 
     SkRect fRect;
     sk_sp<SkLights> fLights;
+    sk_sp<SkLights> fLightsNoDir;
+    sk_sp<SkLights> fLightsTwoDir;
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM(return new LightingShader2GM;)
 }