Raster implementation of diffuse and specular lighting filters. Externally,

the caller instantiates a light (distant, point or spot), and an
SkDiffuseLightingFilter or SkSpecularLightingImageFilter with that light.  A
Sobel edge detection filter is applied to the alpha of the incoming bitmap, and
the result is used as a height map for lighting calculations.

Review URL:  http://codereview.appspot.com/6302101/



git-svn-id: http://skia.googlecode.com/svn/trunk@4314 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 91 insertions, 0 deletions

diff --git a/gm/lighting.cpp b/gm/lighting.cpp
new file mode 100644
index 0000000000..2b41528a38
--- /dev/null
+++ b/gm/lighting.cpp
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2012 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 "SkLightingImageFilter.h"
+
+#define WIDTH 330
+#define HEIGHT 220
+
+namespace skiagm {
+
+class ImageLightingGM : public GM {
+public:
+    ImageLightingGM() : fInitialized(false) {
+        this->setBGColor(0xFF000000);
+    }
+    
+protected:
+    virtual SkString onShortName() {
+        return SkString("lighting");
+    }
+
+    void make_bitmap() {
+        fBitmap.setConfig(SkBitmap::kARGB_8888_Config, 100, 100);
+        fBitmap.allocPixels();
+        SkDevice device(fBitmap);
+        SkCanvas canvas(&device);
+        canvas.clear(0x00000000);
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setColor(0xFFFFFFFF);
+        paint.setTextSize(SkIntToScalar(96));
+        const char* str = "e";
+        canvas.drawText(str, strlen(str), SkIntToScalar(20), SkIntToScalar(70), paint);
+    }
+
+    virtual SkISize onISize() {
+        return make_isize(WIDTH, HEIGHT);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        if (!fInitialized) {
+            make_bitmap();
+            fInitialized = true;
+        }
+        SkPoint3 pointLocation(0, 0, SkIntToScalar(10));
+        SkScalar azimuthRad = SkDegreesToRadians(SkIntToScalar(225));
+        SkScalar elevationRad = SkDegreesToRadians(SkIntToScalar(5));
+        SkPoint3 distantDirection(SkScalarMul(SkScalarCos(azimuthRad), SkScalarCos(elevationRad)),
+                                  SkScalarMul(SkScalarSin(azimuthRad), SkScalarCos(elevationRad)),
+                                  SkScalarSin(elevationRad));
+        SkPoint3 spotLocation(SkIntToScalar(-10), SkIntToScalar(-10), SkIntToScalar(20));
+        SkPoint3 spotTarget(SkIntToScalar(40), SkIntToScalar(40), 0);
+        SkScalar spotExponent = SK_Scalar1;
+        SkScalar cutoffAngle = SkIntToScalar(15);
+        SkScalar kd = SkIntToScalar(2);
+        SkScalar ks = SkIntToScalar(1);
+        SkScalar shininess = SkIntToScalar(8);
+        SkScalar surfaceScale = SkIntToScalar(1);
+        SkColor white(0xFFFFFFFF);
+        SkPaint paint;
+        paint.setImageFilter(SkLightingImageFilter::CreatePointLitDiffuse(pointLocation, white, surfaceScale, kd))->unref();
+        canvas->drawSprite(fBitmap, 0, 0, &paint);
+        paint.setImageFilter(SkLightingImageFilter::CreateDistantLitDiffuse(distantDirection, white, surfaceScale, kd))->unref();
+        canvas->drawSprite(fBitmap, 110, 0, &paint);
+        paint.setImageFilter(SkLightingImageFilter::CreateSpotLitDiffuse(spotLocation, spotTarget, spotExponent, cutoffAngle, white, surfaceScale, kd))->unref();
+        canvas->drawSprite(fBitmap, 220, 0, &paint);
+        paint.setImageFilter(SkLightingImageFilter::CreatePointLitSpecular(pointLocation, white, surfaceScale, ks, shininess))->unref();
+        canvas->drawSprite(fBitmap, 0, 110, &paint);
+        paint.setImageFilter(SkLightingImageFilter::CreateDistantLitSpecular(distantDirection, white, surfaceScale, ks, shininess))->unref();
+        canvas->drawSprite(fBitmap, 110, 110, &paint);
+        paint.setImageFilter(SkLightingImageFilter::CreateSpotLitSpecular(spotLocation, spotTarget, spotExponent, cutoffAngle, white, surfaceScale, ks, shininess))->unref();
+        canvas->drawSprite(fBitmap, 220, 110, &paint);
+    }
+    
+private:
+    typedef GM INHERITED;
+    SkBitmap fBitmap;
+    bool fInitialized;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new ImageLightingGM; }
+static GMRegistry reg(MyFactory);
+
+}