SkiaShader.cpp revision 550780745fa28ae9a87d02331841ca5ce4f9c763 
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.set(gradInfo.fColors[0]);
177        outData->endColor.set(gradInfo.fColors[1]);
178    }
179
180    outData->ditherSampler = (*textureUnit)++;
181    return true;
182}
183
184void applyGradient(Caches& caches, const SkiaShaderData::GradientShaderData& data) {
185    if (CC_UNLIKELY(data.gradientTexture)) {
186        caches.textureState().activateTexture(data.gradientSampler);
187        bindTexture(&caches, data.gradientTexture, data.wrapST, data.wrapST);
188        glUniform1i(caches.program().getUniform("gradientSampler"), data.gradientSampler);
189    } else {
190        bindUniformColor(caches.program().getUniform("startColor"), data.startColor);
191        bindUniformColor(caches.program().getUniform("endColor"), data.endColor);
192    }
193
194    // TODO: remove sampler slot incrementing from dither.setupProgram,
195    // since this assignment of slots is done at store, not apply time
196    GLuint ditherSampler = data.ditherSampler;
197    caches.dither.setupProgram(caches.program(), &ditherSampler);
198    glUniformMatrix4fv(caches.program().getUniform("screenSpace"), 1,
199            GL_FALSE, &data.screenSpace.data[0]);
200}
201
202bool tryStoreBitmap(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
203        GLuint* textureUnit, ProgramDescription* description,
204        SkiaShaderData::BitmapShaderData* outData) {
205    SkBitmap bitmap;
206    SkShader::TileMode xy[2];
207    if (!shader.isABitmap(&bitmap, nullptr, xy)) {
208        return false;
209    }
210
211    /*
212     * Bypass the AssetAtlas, since those textures:
213     * 1) require UV mapping, which isn't implemented in matrix computation below
214     * 2) can't handle REPEAT simply
215     * 3) are safe to upload here (outside of sync stage), since they're static
216     */
217    outData->bitmapTexture = caches.textureCache.getAndBypassAtlas(&bitmap);
218    if (!outData->bitmapTexture) return false;
219
220    outData->bitmapSampler = (*textureUnit)++;
221
222    const float width = outData->bitmapTexture->width;
223    const float height = outData->bitmapTexture->height;
224
225    description->hasBitmap = true;
226    if (!caches.extensions().hasNPot()
227            && (!isPowerOfTwo(width) || !isPowerOfTwo(height))
228            && (xy[0] != SkShader::kClamp_TileMode || xy[1] != SkShader::kClamp_TileMode)) {
229        description->isBitmapNpot = true;
230        description->bitmapWrapS = gTileModes[xy[0]];
231        description->bitmapWrapT = gTileModes[xy[1]];
232
233        outData->wrapS = GL_CLAMP_TO_EDGE;
234        outData->wrapT = GL_CLAMP_TO_EDGE;
235    } else {
236        outData->wrapS = gTileModes[xy[0]];
237        outData->wrapT = gTileModes[xy[1]];
238    }
239
240    computeScreenSpaceMatrix(outData->textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
241            modelViewMatrix);
242    outData->textureDimension[0] = 1.0f / width;
243    outData->textureDimension[1] = 1.0f / height;
244
245    return true;
246}
247
248void applyBitmap(Caches& caches, const SkiaShaderData::BitmapShaderData& data) {
249    caches.textureState().activateTexture(data.bitmapSampler);
250    bindTexture(&caches, data.bitmapTexture, data.wrapS, data.wrapT);
251    data.bitmapTexture->setFilter(GL_LINEAR);
252
253    glUniform1i(caches.program().getUniform("bitmapSampler"), data.bitmapSampler);
254    glUniformMatrix4fv(caches.program().getUniform("textureTransform"), 1, GL_FALSE,
255            &data.textureTransform.data[0]);
256    glUniform2fv(caches.program().getUniform("textureDimension"), 1, &data.textureDimension[0]);
257}
258
259SkiaShaderType getComposeSubType(const SkShader& shader) {
260    // First check for a gradient shader.
261    switch (shader.asAGradient(nullptr)) {
262        case SkShader::kNone_GradientType:
263            // Not a gradient shader. Fall through to check for other types.
264            break;
265        case SkShader::kLinear_GradientType:
266        case SkShader::kRadial_GradientType:
267        case SkShader::kSweep_GradientType:
268            return kGradient_SkiaShaderType;
269        default:
270            // This is a Skia gradient that has no SkiaShader equivalent. Return None to skip.
271            return kNone_SkiaShaderType;
272    }
273
274    // The shader is not a gradient. Check for a bitmap shader.
275    if (shader.isABitmap()) {
276        return kBitmap_SkiaShaderType;
277    }
278    return kNone_SkiaShaderType;
279}
280
281void storeCompose(Caches& caches, const SkShader& bitmapShader, const SkShader& gradientShader,
282        const Matrix4& modelViewMatrix, GLuint* textureUnit,
283        ProgramDescription* description, SkiaShaderData* outData) {
284    LOG_ALWAYS_FATAL_IF(!tryStoreBitmap(caches, bitmapShader, modelViewMatrix,
285                textureUnit, description, &outData->bitmapData),
286            "failed storing bitmap shader data");
287    LOG_ALWAYS_FATAL_IF(!tryStoreGradient(caches, gradientShader, modelViewMatrix,
288                textureUnit, description, &outData->gradientData),
289            "failing storing gradient shader data");
290}
291
292bool tryStoreCompose(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
293        GLuint* textureUnit, ProgramDescription* description,
294        SkiaShaderData* outData) {
295
296    SkShader::ComposeRec rec;
297    if (!shader.asACompose(&rec)) return false;
298
299    const SkiaShaderType shaderAType = getComposeSubType(*rec.fShaderA);
300    const SkiaShaderType shaderBType = getComposeSubType(*rec.fShaderB);
301
302    // check that type enum values are the 2 flags that compose the kCompose value
303    if ((shaderAType & shaderBType) != 0) return false;
304    if ((shaderAType | shaderBType) != kCompose_SkiaShaderType) return false;
305
306    mat4 transform;
307    computeScreenSpaceMatrix(transform, SkMatrix::I(), shader.getLocalMatrix(), modelViewMatrix);
308    if (shaderAType == kBitmap_SkiaShaderType) {
309        description->isBitmapFirst = true;
310        storeCompose(caches, *rec.fShaderA, *rec.fShaderB,
311                transform, textureUnit, description, outData);
312    } else {
313        description->isBitmapFirst = false;
314        storeCompose(caches, *rec.fShaderB, *rec.fShaderA,
315                transform, textureUnit, description, outData);
316    }
317    if (!SkXfermode::AsMode(rec.fMode, &description->shadersMode)) {
318        // TODO: Support other modes.
319        description->shadersMode = SkXfermode::kSrcOver_Mode;
320    }
321    return true;
322}
323
324bool tryStoreLayer(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
325        GLuint* textureUnit, ProgramDescription* description,
326        SkiaShaderData::LayerShaderData* outData) {
327    Layer* layer;
328    if (!shader.asACustomShader(reinterpret_cast<void**>(&layer))) {
329        return false;
330    }
331
332    description->hasBitmap = true;
333    outData->layer = layer;
334    outData->bitmapSampler = (*textureUnit)++;
335
336    const float width = layer->getWidth();
337    const float height = layer->getHeight();
338
339    computeScreenSpaceMatrix(outData->textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
340            modelViewMatrix);
341
342    outData->textureDimension[0] = 1.0f / width;
343    outData->textureDimension[1] = 1.0f / height;
344    return true;
345}
346
347void applyLayer(Caches& caches, const SkiaShaderData::LayerShaderData& data) {
348    caches.textureState().activateTexture(data.bitmapSampler);
349
350    data.layer->bindTexture();
351    data.layer->setWrap(GL_CLAMP_TO_EDGE);
352    data.layer->setFilter(GL_LINEAR);
353
354    glUniform1i(caches.program().getUniform("bitmapSampler"), data.bitmapSampler);
355    glUniformMatrix4fv(caches.program().getUniform("textureTransform"), 1,
356            GL_FALSE, &data.textureTransform.data[0]);
357    glUniform2fv(caches.program().getUniform("textureDimension"), 1, &data.textureDimension[0]);
358}
359
360void SkiaShader::store(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
361        GLuint* textureUnit, ProgramDescription* description,
362        SkiaShaderData* outData) {
363    if (tryStoreGradient(caches, shader, modelViewMatrix,
364            textureUnit, description, &outData->gradientData)) {
365        outData->skiaShaderType = kGradient_SkiaShaderType;
366        return;
367    }
368
369    if (tryStoreBitmap(caches, shader, modelViewMatrix,
370            textureUnit, description, &outData->bitmapData)) {
371        outData->skiaShaderType = kBitmap_SkiaShaderType;
372        return;
373    }
374
375    if (tryStoreCompose(caches, shader, modelViewMatrix,
376            textureUnit, description, outData)) {
377        outData->skiaShaderType = kCompose_SkiaShaderType;
378        return;
379    }
380
381    if (tryStoreLayer(caches, shader, modelViewMatrix,
382            textureUnit, description, &outData->layerData)) {
383        outData->skiaShaderType = kLayer_SkiaShaderType;
384        return;
385    }
386
387    // Unknown/unsupported type, so explicitly ignore shader
388    outData->skiaShaderType = kNone_SkiaShaderType;
389}
390
391void SkiaShader::apply(Caches& caches, const SkiaShaderData& data) {
392    if (!data.skiaShaderType) return;
393
394    if (data.skiaShaderType & kGradient_SkiaShaderType) {
395        applyGradient(caches, data.gradientData);
396    }
397    if (data.skiaShaderType & kBitmap_SkiaShaderType) {
398        applyBitmap(caches, data.bitmapData);
399    }
400
401    if (data.skiaShaderType == kLayer_SkiaShaderType) {
402        applyLayer(caches, data.layerData);
403    }
404}
405
406}; // namespace uirenderer
407}; // namespace android
408