Move LightingShader to effects

Additionally this CL:

forces the light colors to be opaque
forces the light direction to be normalized
adds a raster implementation
adds a gm

Review URL: https://codereview.chromium.org/1245883003

1 files changed, 111 insertions, 0 deletions

diff --git a/gm/lightingshader.cpp b/gm/lightingshader.cpp
new file mode 100644
index 0000000000..e920fb5cc3
--- /dev/null
+++ b/gm/lightingshader.cpp
@@ -0,0 +1,111 @@
+/*
+ * 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"
+
+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),
+                                     16);
+    return bitmap;
+}
+
+// Create a hemispherical normal map
+static SkBitmap make_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 = sqrt(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);
+        }
+    }
+
+    return hemi;
+}
+
+
+namespace skiagm {
+
+// This GM exercises lighting shaders.
+class LightingShaderGM : public GM {
+public:
+    LightingShaderGM() {
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
+    }
+
+protected:
+
+    SkString onShortName() override {
+        return SkString("lightingshader");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kTexSize, kTexSize);
+    }
+
+    void onOnceBeforeDraw() override {
+        fDiffuse = make_checkerboard(kTexSize);
+        fNormalMap = make_normalmap(kTexSize);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+
+        SkColor ambient = SkColorSetRGB(0x1f, 0x1f, 0x1f);
+
+        SkLightingShader::Light light;
+        light.fColor = SkColorSetRGB(0xff, 0xff, 0xff);
+        light.fDirection.fX = 0.0f;
+        light.fDirection.fY = 0.0f;
+        light.fDirection.fZ = 1.0f;
+
+        SkAutoTUnref<SkShader> fShader(SkLightingShader::Create(fDiffuse, fNormalMap, 
+                                                                light, ambient));
+
+        SkPaint paint;
+        paint.setShader(fShader);
+
+        SkRect r = SkRect::MakeWH(SkIntToScalar(kTexSize), SkIntToScalar(kTexSize));
+
+        canvas->drawRect(r, paint);
+    }
+
+private:
+    static const int kTexSize = 128;
+
+    SkBitmap fDiffuse;
+    SkBitmap fNormalMap;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(LightingShaderGM); )
+
+}