1 /*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkBitmapAlphaThresholdShader.h"
9
10 class BATShader : public SkShader {
11 public:
12 SK_DECLARE_INST_COUNT(BATShader);
13
14 BATShader(const SkBitmap& bitmap, SkRegion region, U8CPU);
BATShader(SkFlattenableReadBuffer & buffer)15 BATShader(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
16 // We should probably do something here.
17 }
18
19
shadeSpan(int x,int y,SkPMColor[],int count)20 virtual void shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE {};
21
22 #if SK_SUPPORT_GPU
23 virtual GrEffectRef* asNewEffect(GrContext* context, const SkPaint& paint) const SK_OVERRIDE;
24 #endif
25
26 SK_DEVELOPER_TO_STRING();
27 SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(BATShader)
28
29 private:
30 SkBitmap fBitmap;
31 SkRegion fRegion;
32 U8CPU fThreshold;
33
34 typedef SkShader INHERITED;
35 };
36
Create(const SkBitmap & bitmap,const SkRegion & region,U8CPU threshold)37 SkShader* SkBitmapAlphaThresholdShader::Create(const SkBitmap& bitmap,
38 const SkRegion& region,
39 U8CPU threshold) {
40 SkASSERT(threshold < 256);
41 return SkNEW_ARGS(BATShader, (bitmap, region, threshold));
42 }
43
BATShader(const SkBitmap & bitmap,SkRegion region,U8CPU threshold)44 BATShader::BATShader(const SkBitmap& bitmap, SkRegion region, U8CPU threshold)
45 : fBitmap(bitmap)
46 , fRegion(region)
47 , fThreshold(threshold) {
48 };
49
50
51 #ifdef SK_DEVELOPER
toString(SkString * str) const52 void BATShader::toString(SkString* str) const {
53 str->append("BATShader: (");
54
55 fBitmap.toString(str);
56
57 this->INHERITED::toString(str);
58
59 str->append(")");
60 }
61 #endif
62
63 #if SK_SUPPORT_GPU
64 #include "GrContext.h"
65 #include "GrCoordTransform.h"
66 #include "GrEffect.h"
67 #include "gl/GrGLEffect.h"
68 #include "GrTBackendEffectFactory.h"
69 #include "GrTextureAccess.h"
70
71 #include "SkGr.h"
72
73 /**
74 * Could create specializations for some simple cases:
75 * - The region is empty.
76 * - The region fully contains the bitmap.
77 * - The regions is 1 rect (or maybe a small number of rects).
78 */
79 class ThresholdEffect : public GrEffect {
80 public:
getFactory() const81 virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
82 return GrTBackendEffectFactory<ThresholdEffect>::getInstance();
83 }
84
Create(GrTexture * bmpTexture,const SkMatrix & bmpMatrix,GrTexture * maskTexture,const SkMatrix & maskMatrix,U8CPU threshold)85 static GrEffectRef* Create(GrTexture* bmpTexture, const SkMatrix& bmpMatrix,
86 GrTexture* maskTexture, const SkMatrix& maskMatrix,
87 U8CPU threshold) {
88 SkScalar thresh = SkIntToScalar(threshold) / 255;
89
90 AutoEffectUnref effect(SkNEW_ARGS(ThresholdEffect, (bmpTexture, bmpMatrix,
91 maskTexture, maskMatrix,
92 thresh)));
93 return CreateEffectRef(effect);
94 }
95
getConstantColorComponents(GrColor * color,uint32_t * validFlags) const96 virtual void getConstantColorComponents(GrColor* color,
97 uint32_t* validFlags) const SK_OVERRIDE {
98 if ((kA_GrColorComponentFlag & *validFlags) && 0 == GrColorUnpackA(*color)) {
99 return;
100 }
101 *validFlags = 0;
102 return;
103 }
104
Name()105 static const char* Name() { return "Bitmap Alpha Threshold"; }
106
107 class GLEffect : public GrGLEffect {
108 public:
GLEffect(const GrBackendEffectFactory & factory,const GrDrawEffect & e)109 GLEffect(const GrBackendEffectFactory& factory,
110 const GrDrawEffect& e)
111 : GrGLEffect(factory)
112 , fPrevThreshold(-SK_Scalar1) {
113 }
114
emitCode(GrGLShaderBuilder * builder,const GrDrawEffect & drawEffect,EffectKey key,const char * outputColor,const char * inputColor,const TransformedCoordsArray & coords,const TextureSamplerArray & samplers)115 virtual void emitCode(GrGLShaderBuilder* builder,
116 const GrDrawEffect& drawEffect,
117 EffectKey key,
118 const char* outputColor,
119 const char* inputColor,
120 const TransformedCoordsArray& coords,
121 const TextureSamplerArray& samplers) SK_OVERRIDE {
122 // put bitmap color in "color"
123 builder->fsCodeAppend("\t\tvec4 color = ");
124 builder->fsAppendTextureLookup(samplers[0], coords[0].c_str(), coords[0].type());
125 builder->fsCodeAppend(";\n");
126
127 // put alpha from mask texture in "mask"
128 builder->fsCodeAppend("\t\tfloat mask = ");
129 builder->fsAppendTextureLookup(samplers[1], coords[1].c_str(), coords[1].type());
130 builder->fsCodeAppend(".a;\n");
131
132 const char* threshold;
133
134 fThresholdUniHandle = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
135 kFloat_GrSLType,
136 "threshold",
137 &threshold);
138 builder->fsCodeAppendf("\t\tfloat thresh = %s;\n", threshold);
139
140 builder->fsCodeAppend("\t\tif (mask < 0.5) {\n"
141 "\t\t\tif (color.a > thresh) {\n"
142 "\t\t\t\tfloat scale = thresh / color.a;\n"
143 "\t\t\t\tcolor.rgb *= scale;\n"
144 "\t\t\t\tcolor.a = thresh;\n"
145 "\t\t\t}\n"
146 "\t\t} else if (color.a < thresh) {\n"
147 "\t\t\tfloat scale = thresh / color.a;\n"
148 "\t\t\tcolor.rgb *= scale;\n"
149 "\t\t\tcolor.a = thresh;\n"
150 "\t\t}\n");
151
152 builder->fsCodeAppendf("color = %s = %s;\n", outputColor,
153 (GrGLSLExpr4(inputColor) * GrGLSLExpr4("color")).c_str());
154 }
155
setData(const GrGLUniformManager & uman,const GrDrawEffect & e)156 virtual void setData(const GrGLUniformManager& uman, const GrDrawEffect& e) SK_OVERRIDE {
157 const ThresholdEffect& effect = e.castEffect<ThresholdEffect>();
158 if (fPrevThreshold != effect.fThreshold) {
159 uman.set1f(fThresholdUniHandle, effect.fThreshold);
160 }
161 }
162
163 private:
164 GrGLUniformManager::UniformHandle fThresholdUniHandle;
165 SkScalar fPrevThreshold;
166 };
167
168 GR_DECLARE_EFFECT_TEST;
169
170 private:
ThresholdEffect(GrTexture * bmpTexture,const SkMatrix & bmpMatrix,GrTexture * maskTexture,const SkMatrix & maskMatrix,SkScalar threshold)171 ThresholdEffect(GrTexture* bmpTexture, const SkMatrix& bmpMatrix,
172 GrTexture* maskTexture, const SkMatrix& maskMatrix,
173 SkScalar threshold)
174 : fBmpTransform(kLocal_GrCoordSet, bmpMatrix, bmpTexture)
175 , fBmpAccess(bmpTexture, GrTextureParams())
176 , fMaskTransform(kLocal_GrCoordSet, maskMatrix, maskTexture)
177 , fMaskAccess(maskTexture, GrTextureParams())
178 , fThreshold(threshold) {
179 this->addCoordTransform(&fBmpTransform);
180 this->addTextureAccess(&fBmpAccess);
181 this->addCoordTransform(&fMaskTransform);
182 this->addTextureAccess(&fMaskAccess);
183 }
184
onIsEqual(const GrEffect & other) const185 virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
186 const ThresholdEffect& e = CastEffect<ThresholdEffect>(other);
187 return e.fBmpAccess.getTexture() == fBmpAccess.getTexture() &&
188 e.fMaskAccess.getTexture() == fMaskAccess.getTexture() &&
189 e.fBmpTransform.getMatrix() == fBmpTransform.getMatrix() &&
190 e.fMaskTransform.getMatrix() == fMaskTransform.getMatrix() &&
191 e.fThreshold == fThreshold;
192 }
193
194 GrCoordTransform fBmpTransform;
195 GrTextureAccess fBmpAccess;
196 GrCoordTransform fMaskTransform;
197 GrTextureAccess fMaskAccess;
198
199 SkScalar fThreshold;
200 };
201
202 GR_DEFINE_EFFECT_TEST(ThresholdEffect);
203
TestCreate(SkRandom * rand,GrContext *,const GrDrawTargetCaps &,GrTexture * textures[])204 GrEffectRef* ThresholdEffect::TestCreate(SkRandom* rand,
205 GrContext*,
206 const GrDrawTargetCaps&,
207 GrTexture* textures[]) {
208 GrTexture* bmpTex = textures[GrEffectUnitTest::kSkiaPMTextureIdx];
209 GrTexture* maskTex = textures[GrEffectUnitTest::kAlphaTextureIdx];
210 U8CPU thresh = rand->nextU() % 0xff;
211 return ThresholdEffect::Create(bmpTex, SkMatrix::I(), maskTex, SkMatrix::I(), thresh);
212 }
213
asNewEffect(GrContext * context,const SkPaint & paint) const214 GrEffectRef* BATShader::asNewEffect(GrContext* context, const SkPaint& paint) const {
215 SkMatrix localInverse;
216 if (!this->getLocalMatrix().invert(&localInverse)) {
217 return NULL;
218 }
219
220 GrTextureDesc maskDesc;
221 if (context->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
222 maskDesc.fConfig = kAlpha_8_GrPixelConfig;
223 } else {
224 maskDesc.fConfig = kRGBA_8888_GrPixelConfig;
225 }
226 maskDesc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
227 const SkIRect& bounds = fRegion.getBounds();
228 // Add one pixel of border to ensure that clamp mode will be all zeros
229 // the outside.
230 maskDesc.fWidth = bounds.width() + 2;
231 maskDesc.fHeight = bounds.height() + 2;
232 GrAutoScratchTexture ast(context, maskDesc, GrContext::kApprox_ScratchTexMatch);
233 GrTexture* maskTexture = ast.texture();
234 if (NULL == maskTexture) {
235 return NULL;
236 }
237
238 GrPaint grPaint;
239 grPaint.setBlendFunc(kOne_GrBlendCoeff, kZero_GrBlendCoeff);
240 SkRegion::Iterator iter(fRegion);
241 context->setRenderTarget(maskTexture->asRenderTarget());
242 context->clear(NULL, 0x0, true);
243
244 // offset to ensure border is zero on top/left
245 SkMatrix matrix;
246 matrix.setTranslate(SK_Scalar1, SK_Scalar1);
247 context->setMatrix(matrix);
248
249 while (!iter.done()) {
250 SkRect rect = SkRect::Make(iter.rect());
251 context->drawRect(grPaint, rect);
252 iter.next();
253 }
254
255 GrTexture* bmpTexture = GrLockAndRefCachedBitmapTexture(context, fBitmap, NULL);
256 if (NULL == bmpTexture) {
257 return NULL;
258 }
259
260 SkMatrix bmpMatrix = localInverse;
261 bmpMatrix.postIDiv(bmpTexture->width(), bmpTexture->height());
262
263 SkMatrix maskMatrix = localInverse;
264 // compensate for the border
265 maskMatrix.postTranslate(SK_Scalar1, SK_Scalar1);
266 maskMatrix.postIDiv(maskTexture->width(), maskTexture->height());
267
268 GrEffectRef* effect = ThresholdEffect::Create(bmpTexture, bmpMatrix,
269 maskTexture, maskMatrix,
270 fThreshold);
271
272 GrUnlockAndUnrefCachedBitmapTexture(bmpTexture);
273
274 return effect;
275 }
276
277 #endif
278