SkiaShader.cpp revision 669b15a93548b82135c73196665bcb7f03d87795 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "SkiaShader.h"
18
19#include "Caches.h"
20#include "Extensions.h"
21#include "Matrix.h"
22#include "Texture.h"
23#include "hwui/Bitmap.h"
24
25#include <SkMatrix.h>
26#include <utils/Log.h>
27
28namespace android {
29namespace uirenderer {
30
31///////////////////////////////////////////////////////////////////////////////
32// Support
33///////////////////////////////////////////////////////////////////////////////
34
35static constexpr GLenum gTileModes[] = {
36        GL_CLAMP_TO_EDGE,   // == SkShader::kClamp_TileMode
37        GL_REPEAT,          // == SkShader::kRepeat_Mode
38        GL_MIRRORED_REPEAT  // == SkShader::kMirror_TileMode
39};
40
41static_assert(gTileModes[SkShader::kClamp_TileMode] == GL_CLAMP_TO_EDGE,
42        "SkShader TileModes have changed");
43static_assert(gTileModes[SkShader::kRepeat_TileMode] == GL_REPEAT,
44        "SkShader TileModes have changed");
45static_assert(gTileModes[SkShader::kMirror_TileMode] == GL_MIRRORED_REPEAT,
46        "SkShader TileModes have changed");
47
48/**
49 * This function does not work for n == 0.
50 */
51static inline bool isPowerOfTwo(unsigned int n) {
52    return !(n & (n - 1));
53}
54
55static inline void bindUniformColor(int slot, FloatColor color) {
56    glUniform4fv(slot, 1, reinterpret_cast<const float*>(&color));
57}
58
59static inline void bindTexture(Caches* caches, Texture* texture, GLenum wrapS, GLenum wrapT) {
60    caches->textureState().bindTexture(texture->target(), texture->id());
61    texture->setWrapST(wrapS, wrapT);
62}
63
64/**
65 * Compute the matrix to transform to screen space.
66 * @param screenSpace Output param for the computed matrix.
67 * @param unitMatrix The unit matrix for gradient shaders, as returned by SkShader::asAGradient,
68 *      or identity.
69 * @param localMatrix Local matrix, as returned by SkShader::getLocalMatrix().
70 * @param modelViewMatrix Model view matrix, as supplied by the OpenGLRenderer.
71 */
72static void computeScreenSpaceMatrix(mat4& screenSpace, const SkMatrix& unitMatrix,
73        const SkMatrix& localMatrix, const mat4& modelViewMatrix) {
74    mat4 shaderMatrix;
75    // uses implicit construction
76    shaderMatrix.loadInverse(localMatrix);
77    // again, uses implicit construction
78    screenSpace.loadMultiply(unitMatrix, shaderMatrix);
79    screenSpace.multiply(modelViewMatrix);
80}
81
82///////////////////////////////////////////////////////////////////////////////
83// Gradient shader matrix helpers
84///////////////////////////////////////////////////////////////////////////////
85
86static void toLinearUnitMatrix(const SkPoint pts[2], SkMatrix* matrix) {
87    SkVector vec = pts[1] - pts[0];
88    const float mag = vec.length();
89    const float inv = mag ? 1.0f / mag : 0;
90
91    vec.scale(inv);
92    matrix->setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY);
93    matrix->postTranslate(-pts[0].fX, -pts[0].fY);
94    matrix->postScale(inv, inv);
95}
96
97static void toCircularUnitMatrix(const float x, const float y, const float radius,
98        SkMatrix* matrix) {
99    const float inv = 1.0f / radius;
100    matrix->setTranslate(-x, -y);
101    matrix->postScale(inv, inv);
102}
103
104static void toSweepUnitMatrix(const float x, const float y, SkMatrix* matrix) {
105    matrix->setTranslate(-x, -y);
106}
107
108///////////////////////////////////////////////////////////////////////////////
109// Common gradient code
110///////////////////////////////////////////////////////////////////////////////
111
112static bool isSimpleGradient(const SkShader::GradientInfo& gradInfo) {
113    return gradInfo.fColorCount == 2 && gradInfo.fTileMode == SkShader::kClamp_TileMode;
114}
115
116///////////////////////////////////////////////////////////////////////////////
117// Store / apply
118///////////////////////////////////////////////////////////////////////////////
119
120bool tryStoreGradient(Caches& caches, const SkShader& shader, const Matrix4 modelViewMatrix,
121        GLuint* textureUnit, ProgramDescription* description,
122        SkiaShaderData::GradientShaderData* outData) {
123    SkShader::GradientInfo gradInfo;
124    gradInfo.fColorCount = 0;
125    gradInfo.fColors = nullptr;
126    gradInfo.fColorOffsets = nullptr;
127
128    SkMatrix unitMatrix;
129    switch (shader.asAGradient(&gradInfo)) {
130        case SkShader::kLinear_GradientType:
131            description->gradientType = ProgramDescription::kGradientLinear;
132
133            toLinearUnitMatrix(gradInfo.fPoint, &unitMatrix);
134            break;
135        case SkShader::kRadial_GradientType:
136            description->gradientType = ProgramDescription::kGradientCircular;
137
138            toCircularUnitMatrix(gradInfo.fPoint[0].fX, gradInfo.fPoint[0].fY,
139                    gradInfo.fRadius[0], &unitMatrix);
140            break;
141        case SkShader::kSweep_GradientType:
142            description->gradientType = ProgramDescription::kGradientSweep;
143
144            toSweepUnitMatrix(gradInfo.fPoint[0].fX, gradInfo.fPoint[0].fY, &unitMatrix);
145            break;
146        default:
147            // Do nothing. This shader is unsupported.
148            return false;
149    }
150    description->hasGradient = true;
151    description->isSimpleGradient = isSimpleGradient(gradInfo);
152
153    computeScreenSpaceMatrix(outData->screenSpace, unitMatrix,
154            shader.getLocalMatrix(), modelViewMatrix);
155
156    // re-query shader to get full color / offset data
157    std::unique_ptr<SkColor[]> colorStorage(new SkColor[gradInfo.fColorCount]);
158    std::unique_ptr<SkScalar[]> colorOffsets(new SkScalar[gradInfo.fColorCount]);
159    gradInfo.fColors = &colorStorage[0];
160    gradInfo.fColorOffsets = &colorOffsets[0];
161    shader.asAGradient(&gradInfo);
162
163    if (CC_UNLIKELY(!description->isSimpleGradient)) {
164        outData->gradientSampler = (*textureUnit)++;
165
166#ifndef SK_SCALAR_IS_FLOAT
167    #error Need to convert gradInfo.fColorOffsets to float!
168#endif
169        outData->gradientTexture = caches.gradientCache.get(
170                gradInfo.fColors, gradInfo.fColorOffsets, gradInfo.fColorCount);
171        outData->wrapST = gTileModes[gradInfo.fTileMode];
172    } else {
173        outData->gradientSampler = 0;
174        outData->gradientTexture = nullptr;
175
176        outData->startColor.set(gradInfo.fColors[0]);
177        outData->endColor.set(gradInfo.fColors[1]);
178    }
179
180    return true;
181}
182
183void applyGradient(Caches& caches, const SkiaShaderData::GradientShaderData& data,
184        const GLsizei width, const GLsizei height) {
185
186    if (CC_UNLIKELY(data.gradientTexture)) {
187        caches.textureState().activateTexture(data.gradientSampler);
188        bindTexture(&caches, data.gradientTexture, data.wrapST, data.wrapST);
189        glUniform1i(caches.program().getUniform("gradientSampler"), data.gradientSampler);
190    } else {
191        bindUniformColor(caches.program().getUniform("startColor"), data.startColor);
192        bindUniformColor(caches.program().getUniform("endColor"), data.endColor);
193    }
194
195    glUniform2f(caches.program().getUniform("screenSize"), 1.0f / width, 1.0f / height);
196    glUniformMatrix4fv(caches.program().getUniform("screenSpace"), 1,
197            GL_FALSE, &data.screenSpace.data[0]);
198}
199
200bool tryStoreBitmap(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
201        GLuint* textureUnit, ProgramDescription* description,
202        SkiaShaderData::BitmapShaderData* outData) {
203    SkBitmap bitmap;
204    SkShader::TileMode xy[2];
205    if (!shader.isABitmap(&bitmap, nullptr, xy)) {
206        return false;
207    }
208
209    // TODO: create  hwui-owned BitmapShader.
210    Bitmap* hwuiBitmap = static_cast<Bitmap*>(bitmap.pixelRef());
211    outData->bitmapTexture = caches.textureCache.get(hwuiBitmap);
212    if (!outData->bitmapTexture) return false;
213
214    outData->bitmapSampler = (*textureUnit)++;
215
216    const float width = outData->bitmapTexture->width();
217    const float height = outData->bitmapTexture->height();
218
219    Texture* texture = outData->bitmapTexture;
220
221    description->hasBitmap = true;
222    description->hasLinearTexture = texture->isLinear();
223    description->hasColorSpaceConversion = texture->hasColorSpaceConversion();
224    description->transferFunction = texture->getTransferFunctionType();
225    description->hasTranslucentConversion = texture->blend;
226    description->isShaderBitmapExternal = hwuiBitmap->isHardware();
227    // gralloc doesn't support non-clamp modes
228    if (hwuiBitmap->isHardware() || (!caches.extensions().hasNPot()
229            && (!isPowerOfTwo(width) || !isPowerOfTwo(height))
230            && (xy[0] != SkShader::kClamp_TileMode || xy[1] != SkShader::kClamp_TileMode))) {
231        // need non-clamp mode, but it's not supported for this draw,
232        // so enable custom shader logic to mimic
233        description->useShaderBasedWrap = true;
234        description->bitmapWrapS = gTileModes[xy[0]];
235        description->bitmapWrapT = gTileModes[xy[1]];
236
237        outData->wrapS = GL_CLAMP_TO_EDGE;
238        outData->wrapT = GL_CLAMP_TO_EDGE;
239    } else {
240        outData->wrapS = gTileModes[xy[0]];
241        outData->wrapT = gTileModes[xy[1]];
242    }
243
244    computeScreenSpaceMatrix(outData->textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
245            modelViewMatrix);
246    outData->textureDimension[0] = 1.0f / width;
247    outData->textureDimension[1] = 1.0f / height;
248
249    return true;
250}
251
252void applyBitmap(Caches& caches, const SkiaShaderData::BitmapShaderData& data) {
253    caches.textureState().activateTexture(data.bitmapSampler);
254    bindTexture(&caches, data.bitmapTexture, data.wrapS, data.wrapT);
255    data.bitmapTexture->setFilter(GL_LINEAR);
256
257    glUniform1i(caches.program().getUniform("bitmapSampler"), data.bitmapSampler);
258    glUniformMatrix4fv(caches.program().getUniform("textureTransform"), 1, GL_FALSE,
259            &data.textureTransform.data[0]);
260    glUniform2fv(caches.program().getUniform("textureDimension"), 1, &data.textureDimension[0]);
261}
262
263SkiaShaderType getComposeSubType(const SkShader& shader) {
264    // First check for a gradient shader.
265    switch (shader.asAGradient(nullptr)) {
266        case SkShader::kNone_GradientType:
267            // Not a gradient shader. Fall through to check for other types.
268            break;
269        case SkShader::kLinear_GradientType:
270        case SkShader::kRadial_GradientType:
271        case SkShader::kSweep_GradientType:
272            return kGradient_SkiaShaderType;
273        default:
274            // This is a Skia gradient that has no SkiaShader equivalent. Return None to skip.
275            return kNone_SkiaShaderType;
276    }
277
278    // The shader is not a gradient. Check for a bitmap shader.
279    if (shader.isABitmap()) {
280        return kBitmap_SkiaShaderType;
281    }
282    return kNone_SkiaShaderType;
283}
284
285void storeCompose(Caches& caches, const SkShader& bitmapShader, const SkShader& gradientShader,
286        const Matrix4& modelViewMatrix, GLuint* textureUnit,
287        ProgramDescription* description, SkiaShaderData* outData) {
288    LOG_ALWAYS_FATAL_IF(!tryStoreBitmap(caches, bitmapShader, modelViewMatrix,
289                textureUnit, description, &outData->bitmapData),
290            "failed storing bitmap shader data");
291    LOG_ALWAYS_FATAL_IF(!tryStoreGradient(caches, gradientShader, modelViewMatrix,
292                textureUnit, description, &outData->gradientData),
293            "failing storing gradient shader data");
294}
295
296bool tryStoreCompose(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
297        GLuint* textureUnit, ProgramDescription* description,
298        SkiaShaderData* outData) {
299
300    SkShader::ComposeRec rec;
301    if (!shader.asACompose(&rec)) return false;
302
303    const SkiaShaderType shaderAType = getComposeSubType(*rec.fShaderA);
304    const SkiaShaderType shaderBType = getComposeSubType(*rec.fShaderB);
305
306    // check that type enum values are the 2 flags that compose the kCompose value
307    if ((shaderAType & shaderBType) != 0) return false;
308    if ((shaderAType | shaderBType) != kCompose_SkiaShaderType) return false;
309
310    mat4 transform;
311    computeScreenSpaceMatrix(transform, SkMatrix::I(), shader.getLocalMatrix(), modelViewMatrix);
312    if (shaderAType == kBitmap_SkiaShaderType) {
313        description->isBitmapFirst = true;
314        storeCompose(caches, *rec.fShaderA, *rec.fShaderB,
315                transform, textureUnit, description, outData);
316    } else {
317        description->isBitmapFirst = false;
318        storeCompose(caches, *rec.fShaderB, *rec.fShaderA,
319                transform, textureUnit, description, outData);
320    }
321    description->shadersMode = rec.fBlendMode;
322    return true;
323}
324
325void SkiaShader::store(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
326        GLuint* textureUnit, ProgramDescription* description,
327        SkiaShaderData* outData) {
328    if (tryStoreGradient(caches, shader, modelViewMatrix,
329            textureUnit, description, &outData->gradientData)) {
330        outData->skiaShaderType = kGradient_SkiaShaderType;
331        return;
332    }
333
334    if (tryStoreBitmap(caches, shader, modelViewMatrix,
335            textureUnit, description, &outData->bitmapData)) {
336        outData->skiaShaderType = kBitmap_SkiaShaderType;
337        return;
338    }
339
340    if (tryStoreCompose(caches, shader, modelViewMatrix,
341            textureUnit, description, outData)) {
342        outData->skiaShaderType = kCompose_SkiaShaderType;
343        return;
344    }
345
346    // Unknown/unsupported type, so explicitly ignore shader
347    outData->skiaShaderType = kNone_SkiaShaderType;
348}
349
350void SkiaShader::apply(Caches& caches, const SkiaShaderData& data,
351        const GLsizei width, const GLsizei height) {
352    if (!data.skiaShaderType) return;
353
354    if (data.skiaShaderType & kGradient_SkiaShaderType) {
355        applyGradient(caches, data.gradientData, width, height);
356    }
357    if (data.skiaShaderType & kBitmap_SkiaShaderType) {
358        applyBitmap(caches, data.bitmapData);
359    }
360}
361
362}; // namespace uirenderer
363}; // namespace android
364