skia2/gm/lightingshader.cpp
robertphillips 5f865b9cf1 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
2015-07-29 12:28:04 -07:00

112 lines
3.0 KiB
C++

/*
* 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); )
}