SkiaShader.cpp revision 8762e332e3797fb41929a1c6069207f4906ca329 
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 "Layer.h"
22#include "Matrix.h"
23#include "Texture.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->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(!isSimpleGradient(gradInfo))) {
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.setSRGB(gradInfo.fColors[0]);
177        outData->endColor.setSRGB(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    outData->bitmapTexture = caches.textureCache.get(&bitmap);
210    if (!outData->bitmapTexture) return false;
211
212    outData->bitmapSampler = (*textureUnit)++;
213
214    const float width = outData->bitmapTexture->width();
215    const float height = outData->bitmapTexture->height();
216
217    description->hasBitmap = true;
218    if (!caches.extensions().hasNPot()
219            && (!isPowerOfTwo(width) || !isPowerOfTwo(height))
220            && (xy[0] != SkShader::kClamp_TileMode || xy[1] != SkShader::kClamp_TileMode)) {
221        description->isBitmapNpot = true;
222        description->bitmapWrapS = gTileModes[xy[0]];
223        description->bitmapWrapT = gTileModes[xy[1]];
224
225        outData->wrapS = GL_CLAMP_TO_EDGE;
226        outData->wrapT = GL_CLAMP_TO_EDGE;
227    } else {
228        outData->wrapS = gTileModes[xy[0]];
229        outData->wrapT = gTileModes[xy[1]];
230    }
231
232    computeScreenSpaceMatrix(outData->textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
233            modelViewMatrix);
234    outData->textureDimension[0] = 1.0f / width;
235    outData->textureDimension[1] = 1.0f / height;
236
237    return true;
238}
239
240void applyBitmap(Caches& caches, const SkiaShaderData::BitmapShaderData& data) {
241    caches.textureState().activateTexture(data.bitmapSampler);
242    bindTexture(&caches, data.bitmapTexture, data.wrapS, data.wrapT);
243    data.bitmapTexture->setFilter(GL_LINEAR);
244
245    glUniform1i(caches.program().getUniform("bitmapSampler"), data.bitmapSampler);
246    glUniformMatrix4fv(caches.program().getUniform("textureTransform"), 1, GL_FALSE,
247            &data.textureTransform.data[0]);
248    glUniform2fv(caches.program().getUniform("textureDimension"), 1, &data.textureDimension[0]);
249}
250
251SkiaShaderType getComposeSubType(const SkShader& shader) {
252    // First check for a gradient shader.
253    switch (shader.asAGradient(nullptr)) {
254        case SkShader::kNone_GradientType:
255            // Not a gradient shader. Fall through to check for other types.
256            break;
257        case SkShader::kLinear_GradientType:
258        case SkShader::kRadial_GradientType:
259        case SkShader::kSweep_GradientType:
260            return kGradient_SkiaShaderType;
261        default:
262            // This is a Skia gradient that has no SkiaShader equivalent. Return None to skip.
263            return kNone_SkiaShaderType;
264    }
265
266    // The shader is not a gradient. Check for a bitmap shader.
267    if (shader.isABitmap()) {
268        return kBitmap_SkiaShaderType;
269    }
270    return kNone_SkiaShaderType;
271}
272
273void storeCompose(Caches& caches, const SkShader& bitmapShader, const SkShader& gradientShader,
274        const Matrix4& modelViewMatrix, GLuint* textureUnit,
275        ProgramDescription* description, SkiaShaderData* outData) {
276    LOG_ALWAYS_FATAL_IF(!tryStoreBitmap(caches, bitmapShader, modelViewMatrix,
277                textureUnit, description, &outData->bitmapData),
278            "failed storing bitmap shader data");
279    LOG_ALWAYS_FATAL_IF(!tryStoreGradient(caches, gradientShader, modelViewMatrix,
280                textureUnit, description, &outData->gradientData),
281            "failing storing gradient shader data");
282}
283
284bool tryStoreCompose(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
285        GLuint* textureUnit, ProgramDescription* description,
286        SkiaShaderData* outData) {
287
288    SkShader::ComposeRec rec;
289    if (!shader.asACompose(&rec)) return false;
290
291    const SkiaShaderType shaderAType = getComposeSubType(*rec.fShaderA);
292    const SkiaShaderType shaderBType = getComposeSubType(*rec.fShaderB);
293
294    // check that type enum values are the 2 flags that compose the kCompose value
295    if ((shaderAType & shaderBType) != 0) return false;
296    if ((shaderAType | shaderBType) != kCompose_SkiaShaderType) return false;
297
298    mat4 transform;
299    computeScreenSpaceMatrix(transform, SkMatrix::I(), shader.getLocalMatrix(), modelViewMatrix);
300    if (shaderAType == kBitmap_SkiaShaderType) {
301        description->isBitmapFirst = true;
302        storeCompose(caches, *rec.fShaderA, *rec.fShaderB,
303                transform, textureUnit, description, outData);
304    } else {
305        description->isBitmapFirst = false;
306        storeCompose(caches, *rec.fShaderB, *rec.fShaderA,
307                transform, textureUnit, description, outData);
308    }
309    if (!SkXfermode::AsMode(rec.fMode, &description->shadersMode)) {
310        // TODO: Support other modes.
311        description->shadersMode = SkXfermode::kSrcOver_Mode;
312    }
313    return true;
314}
315
316bool tryStoreLayer(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
317        GLuint* textureUnit, ProgramDescription* description,
318        SkiaShaderData::LayerShaderData* outData) {
319    Layer* layer;
320    if (!shader.asACustomShader(reinterpret_cast<void**>(&layer))) {
321        return false;
322    }
323
324    description->hasBitmap = true;
325    outData->layer = layer;
326    outData->bitmapSampler = (*textureUnit)++;
327
328    const float width = layer->getWidth();
329    const float height = layer->getHeight();
330
331    computeScreenSpaceMatrix(outData->textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
332            modelViewMatrix);
333
334    outData->textureDimension[0] = 1.0f / width;
335    outData->textureDimension[1] = 1.0f / height;
336    return true;
337}
338
339void applyLayer(Caches& caches, const SkiaShaderData::LayerShaderData& data) {
340    caches.textureState().activateTexture(data.bitmapSampler);
341
342    data.layer->bindTexture();
343    data.layer->setWrap(GL_CLAMP_TO_EDGE);
344    data.layer->setFilter(GL_LINEAR);
345
346    glUniform1i(caches.program().getUniform("bitmapSampler"), data.bitmapSampler);
347    glUniformMatrix4fv(caches.program().getUniform("textureTransform"), 1,
348            GL_FALSE, &data.textureTransform.data[0]);
349    glUniform2fv(caches.program().getUniform("textureDimension"), 1, &data.textureDimension[0]);
350}
351
352void SkiaShader::store(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
353        GLuint* textureUnit, ProgramDescription* description,
354        SkiaShaderData* outData) {
355    if (tryStoreGradient(caches, shader, modelViewMatrix,
356            textureUnit, description, &outData->gradientData)) {
357        outData->skiaShaderType = kGradient_SkiaShaderType;
358        return;
359    }
360
361    if (tryStoreBitmap(caches, shader, modelViewMatrix,
362            textureUnit, description, &outData->bitmapData)) {
363        outData->skiaShaderType = kBitmap_SkiaShaderType;
364        return;
365    }
366
367    if (tryStoreCompose(caches, shader, modelViewMatrix,
368            textureUnit, description, outData)) {
369        outData->skiaShaderType = kCompose_SkiaShaderType;
370        return;
371    }
372
373    if (tryStoreLayer(caches, shader, modelViewMatrix,
374            textureUnit, description, &outData->layerData)) {
375        outData->skiaShaderType = kLayer_SkiaShaderType;
376        return;
377    }
378
379    // Unknown/unsupported type, so explicitly ignore shader
380    outData->skiaShaderType = kNone_SkiaShaderType;
381}
382
383void SkiaShader::apply(Caches& caches, const SkiaShaderData& data,
384        const GLsizei width, const GLsizei height) {
385    if (!data.skiaShaderType) return;
386
387    if (data.skiaShaderType & kGradient_SkiaShaderType) {
388        applyGradient(caches, data.gradientData, width, height);
389    }
390    if (data.skiaShaderType & kBitmap_SkiaShaderType) {
391        applyBitmap(caches, data.bitmapData);
392    }
393
394    if (data.skiaShaderType == kLayer_SkiaShaderType) {
395        applyLayer(caches, data.layerData);
396    }
397}
398
399}; // namespace uirenderer
400}; // namespace android
401