SkiaShader.cpp revision 1bcacfdcab0eaa0cee92bd7f5a1b5e271dd68e52 
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, gradInfo.fRadius[0],
139                                 &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, shader.getLocalMatrix(),
154                             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    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    glUniform2f(caches.program().getUniform("screenSize"), 1.0f / width, 1.0f / height);
195    glUniformMatrix4fv(caches.program().getUniform("screenSpace"), 1, GL_FALSE,
196                       &data.screenSpace.data[0]);
197}
198
199bool tryStoreBitmap(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
200                    GLuint* textureUnit, ProgramDescription* description,
201                    SkiaShaderData::BitmapShaderData* outData) {
202    SkBitmap bitmap;
203    SkShader::TileMode xy[2];
204    if (!shader.isABitmap(&bitmap, nullptr, xy)) {
205        return false;
206    }
207
208    // TODO: create  hwui-owned BitmapShader.
209    Bitmap* hwuiBitmap = static_cast<Bitmap*>(bitmap.pixelRef());
210    outData->bitmapTexture = caches.textureCache.get(hwuiBitmap);
211    if (!outData->bitmapTexture) return false;
212
213    outData->bitmapSampler = (*textureUnit)++;
214
215    const float width = outData->bitmapTexture->width();
216    const float height = outData->bitmapTexture->height();
217
218    Texture* texture = outData->bitmapTexture;
219
220    description->hasBitmap = true;
221    description->hasLinearTexture = texture->isLinear();
222    description->hasColorSpaceConversion = texture->hasColorSpaceConversion();
223    description->transferFunction = texture->getTransferFunctionType();
224    description->hasTranslucentConversion = texture->blend;
225    description->isShaderBitmapExternal = hwuiBitmap->isHardware();
226    // gralloc doesn't support non-clamp modes
227    if (hwuiBitmap->isHardware() ||
228        (!caches.extensions().hasNPot() && (!isPowerOfTwo(width) || !isPowerOfTwo(height)) &&
229         (xy[0] != SkShader::kClamp_TileMode || xy[1] != SkShader::kClamp_TileMode))) {
230        // need non-clamp mode, but it's not supported for this draw,
231        // so enable custom shader logic to mimic
232        description->useShaderBasedWrap = true;
233        description->bitmapWrapS = gTileModes[xy[0]];
234        description->bitmapWrapT = gTileModes[xy[1]];
235
236        outData->wrapS = GL_CLAMP_TO_EDGE;
237        outData->wrapT = GL_CLAMP_TO_EDGE;
238    } else {
239        outData->wrapS = gTileModes[xy[0]];
240        outData->wrapT = gTileModes[xy[1]];
241    }
242
243    computeScreenSpaceMatrix(outData->textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
244                             modelViewMatrix);
245    outData->textureDimension[0] = 1.0f / width;
246    outData->textureDimension[1] = 1.0f / height;
247
248    return true;
249}
250
251void applyBitmap(Caches& caches, const SkiaShaderData::BitmapShaderData& data) {
252    caches.textureState().activateTexture(data.bitmapSampler);
253    bindTexture(&caches, data.bitmapTexture, data.wrapS, data.wrapT);
254    data.bitmapTexture->setFilter(GL_LINEAR);
255
256    glUniform1i(caches.program().getUniform("bitmapSampler"), data.bitmapSampler);
257    glUniformMatrix4fv(caches.program().getUniform("textureTransform"), 1, GL_FALSE,
258                       &data.textureTransform.data[0]);
259    glUniform2fv(caches.program().getUniform("textureDimension"), 1, &data.textureDimension[0]);
260}
261
262SkiaShaderType getComposeSubType(const SkShader& shader) {
263    // First check for a gradient shader.
264    switch (shader.asAGradient(nullptr)) {
265        case SkShader::kNone_GradientType:
266            // Not a gradient shader. Fall through to check for other types.
267            break;
268        case SkShader::kLinear_GradientType:
269        case SkShader::kRadial_GradientType:
270        case SkShader::kSweep_GradientType:
271            return kGradient_SkiaShaderType;
272        default:
273            // This is a Skia gradient that has no SkiaShader equivalent. Return None to skip.
274            return kNone_SkiaShaderType;
275    }
276
277    // The shader is not a gradient. Check for a bitmap shader.
278    if (shader.isABitmap()) {
279        return kBitmap_SkiaShaderType;
280    }
281    return kNone_SkiaShaderType;
282}
283
284void storeCompose(Caches& caches, const SkShader& bitmapShader, const SkShader& gradientShader,
285                  const Matrix4& modelViewMatrix, GLuint* textureUnit,
286                  ProgramDescription* description, SkiaShaderData* outData) {
287    LOG_ALWAYS_FATAL_IF(!tryStoreBitmap(caches, bitmapShader, modelViewMatrix, textureUnit,
288                                        description, &outData->bitmapData),
289                        "failed storing bitmap shader data");
290    LOG_ALWAYS_FATAL_IF(!tryStoreGradient(caches, gradientShader, modelViewMatrix, textureUnit,
291                                          description, &outData->gradientData),
292                        "failing storing gradient shader data");
293}
294
295bool tryStoreCompose(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
296                     GLuint* textureUnit, ProgramDescription* description,
297                     SkiaShaderData* outData) {
298    SkShader::ComposeRec rec;
299    if (!shader.asACompose(&rec)) return false;
300
301    const SkiaShaderType shaderAType = getComposeSubType(*rec.fShaderA);
302    const SkiaShaderType shaderBType = getComposeSubType(*rec.fShaderB);
303
304    // check that type enum values are the 2 flags that compose the kCompose value
305    if ((shaderAType & shaderBType) != 0) return false;
306    if ((shaderAType | shaderBType) != kCompose_SkiaShaderType) return false;
307
308    mat4 transform;
309    computeScreenSpaceMatrix(transform, SkMatrix::I(), shader.getLocalMatrix(), modelViewMatrix);
310    if (shaderAType == kBitmap_SkiaShaderType) {
311        description->isBitmapFirst = true;
312        storeCompose(caches, *rec.fShaderA, *rec.fShaderB, transform, textureUnit, description,
313                     outData);
314    } else {
315        description->isBitmapFirst = false;
316        storeCompose(caches, *rec.fShaderB, *rec.fShaderA, transform, textureUnit, description,
317                     outData);
318    }
319    description->shadersMode = rec.fBlendMode;
320    return true;
321}
322
323void SkiaShader::store(Caches& caches, const SkShader& shader, const Matrix4& modelViewMatrix,
324                       GLuint* textureUnit, ProgramDescription* description,
325                       SkiaShaderData* outData) {
326    if (tryStoreGradient(caches, shader, modelViewMatrix, textureUnit, description,
327                         &outData->gradientData)) {
328        outData->skiaShaderType = kGradient_SkiaShaderType;
329        return;
330    }
331
332    if (tryStoreBitmap(caches, shader, modelViewMatrix, textureUnit, description,
333                       &outData->bitmapData)) {
334        outData->skiaShaderType = kBitmap_SkiaShaderType;
335        return;
336    }
337
338    if (tryStoreCompose(caches, shader, modelViewMatrix, textureUnit, description, outData)) {
339        outData->skiaShaderType = kCompose_SkiaShaderType;
340        return;
341    }
342
343    // Unknown/unsupported type, so explicitly ignore shader
344    outData->skiaShaderType = kNone_SkiaShaderType;
345}
346
347void SkiaShader::apply(Caches& caches, const SkiaShaderData& data, const GLsizei width,
348                       const GLsizei height) {
349    if (!data.skiaShaderType) return;
350
351    if (data.skiaShaderType & kGradient_SkiaShaderType) {
352        applyGradient(caches, data.gradientData, width, height);
353    }
354    if (data.skiaShaderType & kBitmap_SkiaShaderType) {
355        applyBitmap(caches, data.bitmapData);
356    }
357}
358
359};  // namespace uirenderer
360};  // namespace android
361