Move normal map creation methods to sk_tools

gm/lightingshader.cpp

 /*
  * Copyright 2015 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 "SkColorPriv.h"
 #include "SkLightingShader.h"
+#include "SkPoint3.h"
+#include "SkShader.h"
 
 static SkBitmap make_checkerboard(int texSize) {
     SkBitmap bitmap;
     bitmap.allocN32Pixels(texSize, texSize);
 
     SkCanvas canvas(bitmap);
     sk_tool_utils::draw_checkerboard(&canvas,
                                      sk_tool_utils::color_to_565(0x0),
                                      sk_tool_utils::color_to_565(0xFF804020),
                                      2);
     return bitmap;
 }
 
 // Create a hemispherical normal map
 static SkBitmap make_hemi_normalmap(int texSize) {
     SkBitmap hemi;
     hemi.allocN32Pixels(texSize, texSize);
 
-    for (int y = 0; y < texSize; ++y) {
-        for (int x = 0; x < texSize; ++x) {
-            SkScalar locX = (x + 0.5f - texSize/2.0f) / (texSize/2.0f);
-            SkScalar locY = (y + 0.5f - texSize/2.0f) / (texSize/2.0f);
-            
-            SkScalar locZ = locX * locX + locY * locY;
-            if (locZ >= 1.0f) {
-                locX = 0.0f;
-                locY = 0.0f;
-                locZ = 0.0f;
-            }
-            locZ = sqrtf(1.0f - locZ);
-            unsigned char r = static_cast<unsigned char>((0.5f * locX + 0.5f) * 255);
-            unsigned char g = static_cast<unsigned char>((-0.5f * locY + 0.5f) * 255);
-            unsigned char b = static_cast<unsigned char>((0.5f * locZ + 0.5f) * 255);
-            *hemi.getAddr32(x, y) = SkPackARGB32(0xFF, r, g, b);
-        }
-    }
-
+    sk_tool_utils::create_hemi_normal_map(&hemi, SkIRect::MakeWH(texSize, texSize));
     return hemi;
 }
 
 // Create a truncated pyramid normal map
 static SkBitmap make_frustum_normalmap(int texSize) {
     SkBitmap frustum;
     frustum.allocN32Pixels(texSize, texSize);
 
-    SkIRect inner = SkIRect::MakeWH(texSize, texSize);
-    inner.inset(texSize/4, texSize/4);
+    sk_tool_utils::create_frustum_normal_map(&frustum, SkIRect::MakeWH(texSize, texSize));
+    return frustum;
+}
 
-    SkPoint3 norm;
-    const SkPoint3 left =  SkPoint3::Make(-SK_ScalarRoot2Over2, 0.0f, SK_ScalarRoot2Over2);
-    const SkPoint3 up =    SkPoint3::Make(0.0f, -SK_ScalarRoot2Over2, SK_ScalarRoot2Over2);
-    const SkPoint3 right = SkPoint3::Make(SK_ScalarRoot2Over2,  0.0f, SK_ScalarRoot2Over2);
-    const SkPoint3 down =  SkPoint3::Make(0.0f,  SK_ScalarRoot2Over2, SK_ScalarRoot2Over2);
+// Create a tetrahedral normal map
+static SkBitmap make_tetra_normalmap(int texSize) {
+    SkBitmap tetra;
+    tetra.allocN32Pixels(texSize, texSize);
 
-    for (int y = 0; y < texSize; ++y) {
-        for (int x = 0; x < texSize; ++x) {
-            if (inner.contains(x, y)) {
-                norm.set(0.0f, 0.0f, 1.0f);
-            } else {
-                SkScalar locX = x + 0.5f - texSize/2.0f;
-                SkScalar locY = y + 0.5f - texSize/2.0f;
-
-                if (locX >= 0.0f) {
-                    if (locY > 0.0f) {
-                        norm = locX >= locY ? right : down;   // LR corner
-                    } else {
-                        norm = locX > -locY ? right : up;     // UR corner
-                    }    
-                } else {
-                    if (locY > 0.0f) {
-                        norm = -locX > locY ? left : down;    // LL corner
-                    } else {
-                        norm = locX > locY ? up : left;       // UL corner
-                    }    
-                }
-            }
-
-            SkASSERT(SkScalarNearlyEqual(norm.length(), 1.0f));
-            unsigned char r = static_cast<unsigned char>((0.5f *  norm.fX + 0.5f) * 255);
-            unsigned char g = static_cast<unsigned char>((-0.5f * norm.fY + 0.5f) * 255);
-            unsigned char b = static_cast<unsigned char>((0.5f *  norm.fZ + 0.5f) * 255);
-            *frustum.getAddr32(x, y) = SkPackARGB32(0xFF, r, g, b);
-        }
-    }
-
-    return frustum;
+    sk_tool_utils::create_tetra_normal_map(&tetra, SkIRect::MakeWH(texSize, texSize));
+    return tetra;
 }
 
 namespace skiagm {
 
 // This GM exercises lighting shaders.
 class LightingShaderGM : public GM {
 public:
     LightingShaderGM() {
         this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
 
         fLight.fColor = SkColor3f::Make(1.0f, 1.0f, 1.0f);
-        fLight.fDirection.fX = 0.0f;
-        fLight.fDirection.fY = 0.0f;
-        fLight.fDirection.fZ = 1.0f;
+        fLight.fDirection = SkVector3::Make(0.0f, 0.0f, 1.0f);
 
         fAmbient = SkColor3f::Make(0.1f, 0.1f, 0.1f);
     }
 
 protected:
+    enum NormalMap {
+        kHemi_NormalMap,
+        kFrustum_NormalMap,
+        kTetra_NormalMap,
+
+        kLast_NormalMap = kTetra_NormalMap
+    };
+
+    static const int kNormalMapCount = kLast_NormalMap+1;
 
     SkString onShortName() override {
         return SkString("lightingshader");
     }
 
     SkISize onISize() override {
         return SkISize::Make(kGMSize, kGMSize);
     }
 
     void onOnceBeforeDraw() override {
         fDiffuse = make_checkerboard(kTexSize);
-        fHemiNormalMap = make_hemi_normalmap(kTexSize);
-        fFrustumNormalMap = make_frustum_normalmap(kTexSize);
+
+        fNormalMaps[kHemi_NormalMap]    = make_hemi_normalmap(kTexSize);
+        fNormalMaps[kFrustum_NormalMap] = make_frustum_normalmap(kTexSize);
+        fNormalMaps[kTetra_NormalMap]   = make_tetra_normalmap(kTexSize);
     }
 
-    void drawRect(SkCanvas* canvas, const SkRect& r, bool hemi) {
+    void drawRect(SkCanvas* canvas, const SkRect& r, NormalMap mapType) {
 
         SkRect bitmapBounds = SkRect::MakeIWH(fDiffuse.width(), fDiffuse.height());
 
         SkMatrix matrix;
         matrix.setRectToRect(bitmapBounds, r, SkMatrix::kFill_ScaleToFit);
     
         SkAutoTUnref<SkShader> fShader(SkLightingShader::Create(
                                                         fDiffuse,
-                                                        hemi ? fHemiNormalMap : fFrustumNormalMap, 
+                                                        fNormalMaps[mapType],
                                                         fLight, fAmbient,
                                                         &matrix));
 
         SkPaint paint;
         paint.setShader(fShader);
 
         canvas->drawRect(r, paint);
     }
 
     void onDraw(SkCanvas* canvas) override {
         SkRect r = SkRect::MakeWH(SkIntToScalar(kTexSize), SkIntToScalar(kTexSize));
-        this->drawRect(canvas, r, true);
+        this->drawRect(canvas, r, kHemi_NormalMap);
 
         r.offset(kGMSize - kTexSize, 0);
-        this->drawRect(canvas, r, false);
+        this->drawRect(canvas, r, kFrustum_NormalMap);
 
         r.offset(0, kGMSize - kTexSize);
-        this->drawRect(canvas, r, true);
+        this->drawRect(canvas, r, kTetra_NormalMap);
 
         r.offset(kTexSize - kGMSize, 0);
-        this->drawRect(canvas, r, false);
+        this->drawRect(canvas, r, kHemi_NormalMap);
     }
 
 private:
     static const int kTexSize = 128;
     static const int kGMSize  = 512;
 
     SkBitmap                fDiffuse;
-    SkBitmap                fHemiNormalMap;
-    SkBitmap                fFrustumNormalMap;
+    SkBitmap                fNormalMaps[kNormalMapCount];
 
     SkLightingShader::Light fLight;
     SkColor3f               fAmbient;
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return SkNEW(LightingShaderGM); )
 
 }