OpenGLRenderer.cpp revision 06f96e2652e4855b6520ad9dd70583677605b79a 
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#define LOG_TAG "OpenGLRenderer"
18
19#include <stdlib.h>
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <SkCanvas.h>
24#include <SkTypeface.h>
25
26#include <cutils/properties.h>
27#include <utils/Log.h>
28
29#include "OpenGLRenderer.h"
30#include "Properties.h"
31
32namespace android {
33namespace uirenderer {
34
35///////////////////////////////////////////////////////////////////////////////
36// Defines
37///////////////////////////////////////////////////////////////////////////////
38
39#define DEFAULT_TEXTURE_CACHE_SIZE 20.0f
40#define DEFAULT_LAYER_CACHE_SIZE 10.0f
41#define DEFAULT_PATCH_CACHE_SIZE 100
42#define DEFAULT_GRADIENT_CACHE_SIZE 0.5f
43
44#define REQUIRED_TEXTURE_UNITS_COUNT 3
45
46// Converts a number of mega-bytes into bytes
47#define MB(s) s * 1024 * 1024
48
49// Generates simple and textured vertices
50#define FV(x, y, u, v) { { x, y }, { u, v } }
51
52///////////////////////////////////////////////////////////////////////////////
53// Globals
54///////////////////////////////////////////////////////////////////////////////
55
56// This array is never used directly but used as a memcpy source in the
57// OpenGLRenderer constructor
58static const TextureVertex gMeshVertices[] = {
59        FV(0.0f, 0.0f, 0.0f, 0.0f),
60        FV(1.0f, 0.0f, 1.0f, 0.0f),
61        FV(0.0f, 1.0f, 0.0f, 1.0f),
62        FV(1.0f, 1.0f, 1.0f, 1.0f)
63};
64static const GLsizei gMeshStride = sizeof(TextureVertex);
65static const GLsizei gMeshCount = 4;
66
67/**
68 * Structure mapping Skia xfermodes to OpenGL blending factors.
69 */
70struct Blender {
71    SkXfermode::Mode mode;
72    GLenum src;
73    GLenum dst;
74}; // struct Blender
75
76// In this array, the index of each Blender equals the value of the first
77// entry. For instance, gBlends[1] == gBlends[SkXfermode::kSrc_Mode]
78static const Blender gBlends[] = {
79        { SkXfermode::kClear_Mode,   GL_ZERO,                 GL_ZERO },
80        { SkXfermode::kSrc_Mode,     GL_ONE,                  GL_ZERO },
81        { SkXfermode::kDst_Mode,     GL_ZERO,                 GL_ONE },
82        { SkXfermode::kSrcOver_Mode, GL_ONE,                  GL_ONE_MINUS_SRC_ALPHA },
83        { SkXfermode::kDstOver_Mode, GL_ONE_MINUS_DST_ALPHA,  GL_ONE },
84        { SkXfermode::kSrcIn_Mode,   GL_DST_ALPHA,            GL_ZERO },
85        { SkXfermode::kDstIn_Mode,   GL_ZERO,                 GL_SRC_ALPHA },
86        { SkXfermode::kSrcOut_Mode,  GL_ONE_MINUS_DST_ALPHA,  GL_ZERO },
87        { SkXfermode::kDstOut_Mode,  GL_ZERO,                 GL_ONE_MINUS_SRC_ALPHA },
88        { SkXfermode::kSrcATop_Mode, GL_DST_ALPHA,            GL_ONE_MINUS_SRC_ALPHA },
89        { SkXfermode::kDstATop_Mode, GL_ONE_MINUS_DST_ALPHA,  GL_SRC_ALPHA },
90        { SkXfermode::kXor_Mode,     GL_ONE_MINUS_DST_ALPHA,  GL_ONE_MINUS_SRC_ALPHA }
91};
92
93static const GLenum gTextureUnits[] = {
94        GL_TEXTURE0,
95        GL_TEXTURE1,
96        GL_TEXTURE2
97};
98
99///////////////////////////////////////////////////////////////////////////////
100// Constructors/destructor
101///////////////////////////////////////////////////////////////////////////////
102
103OpenGLRenderer::OpenGLRenderer():
104        mBlend(false), mLastSrcMode(GL_ZERO), mLastDstMode(GL_ZERO),
105        mTextureCache(MB(DEFAULT_TEXTURE_CACHE_SIZE)),
106        mLayerCache(MB(DEFAULT_LAYER_CACHE_SIZE)),
107        mGradientCache(MB(DEFAULT_GRADIENT_CACHE_SIZE)),
108        mPatchCache(DEFAULT_PATCH_CACHE_SIZE) {
109    LOGD("Create OpenGLRenderer");
110
111    char property[PROPERTY_VALUE_MAX];
112    if (property_get(PROPERTY_TEXTURE_CACHE_SIZE, property, NULL) > 0) {
113        LOGD("  Setting texture cache size to %sMB", property);
114        mTextureCache.setMaxSize(MB(atof(property)));
115    } else {
116        LOGD("  Using default texture cache size of %.2fMB", DEFAULT_TEXTURE_CACHE_SIZE);
117    }
118
119    if (property_get(PROPERTY_LAYER_CACHE_SIZE, property, NULL) > 0) {
120        LOGD("  Setting layer cache size to %sMB", property);
121        mLayerCache.setMaxSize(MB(atof(property)));
122    } else {
123        LOGD("  Using default layer cache size of %.2fMB", DEFAULT_LAYER_CACHE_SIZE);
124    }
125
126    if (property_get(PROPERTY_GRADIENT_CACHE_SIZE, property, NULL) > 0) {
127        LOGD("  Setting gradient cache size to %sMB", property);
128        mLayerCache.setMaxSize(MB(atof(property)));
129    } else {
130        LOGD("  Using default gradient cache size of %.2fMB", DEFAULT_GRADIENT_CACHE_SIZE);
131    }
132
133    mCurrentProgram = NULL;
134    mShader = NULL;
135
136    memcpy(mMeshVertices, gMeshVertices, sizeof(gMeshVertices));
137
138    mFirstSnapshot = new Snapshot;
139
140    GLint maxTextureUnits;
141    glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &maxTextureUnits);
142    if (maxTextureUnits < REQUIRED_TEXTURE_UNITS_COUNT) {
143        LOGW("At least %d texture units are required!", REQUIRED_TEXTURE_UNITS_COUNT);
144    }
145}
146
147OpenGLRenderer::~OpenGLRenderer() {
148    LOGD("Destroy OpenGLRenderer");
149
150    mTextureCache.clear();
151    mLayerCache.clear();
152    mGradientCache.clear();
153    mPatchCache.clear();
154}
155
156///////////////////////////////////////////////////////////////////////////////
157// Setup
158///////////////////////////////////////////////////////////////////////////////
159
160void OpenGLRenderer::setViewport(int width, int height) {
161    glViewport(0, 0, width, height);
162
163    mOrthoMatrix.loadOrtho(0, width, height, 0, -1, 1);
164
165    mWidth = width;
166    mHeight = height;
167    mFirstSnapshot->height = height;
168}
169
170void OpenGLRenderer::prepare() {
171    mSnapshot = new Snapshot(mFirstSnapshot);
172    mSaveCount = 0;
173
174    glDisable(GL_SCISSOR_TEST);
175
176    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
177    glClear(GL_COLOR_BUFFER_BIT);
178
179    glEnable(GL_SCISSOR_TEST);
180    glScissor(0, 0, mWidth, mHeight);
181
182    mSnapshot->setClip(0.0f, 0.0f, mWidth, mHeight);
183}
184
185///////////////////////////////////////////////////////////////////////////////
186// State management
187///////////////////////////////////////////////////////////////////////////////
188
189int OpenGLRenderer::getSaveCount() const {
190    return mSaveCount;
191}
192
193int OpenGLRenderer::save(int flags) {
194    return saveSnapshot();
195}
196
197void OpenGLRenderer::restore() {
198    if (mSaveCount == 0) return;
199
200    if (restoreSnapshot()) {
201        setScissorFromClip();
202    }
203}
204
205void OpenGLRenderer::restoreToCount(int saveCount) {
206    if (saveCount <= 0 || saveCount > mSaveCount) return;
207
208    bool restoreClip = false;
209
210    while (mSaveCount != saveCount - 1) {
211        restoreClip |= restoreSnapshot();
212    }
213
214    if (restoreClip) {
215        setScissorFromClip();
216    }
217}
218
219int OpenGLRenderer::saveSnapshot() {
220    mSnapshot = new Snapshot(mSnapshot);
221    return ++mSaveCount;
222}
223
224bool OpenGLRenderer::restoreSnapshot() {
225    bool restoreClip = mSnapshot->flags & Snapshot::kFlagClipSet;
226    bool restoreLayer = mSnapshot->flags & Snapshot::kFlagIsLayer;
227    bool restoreOrtho = mSnapshot->flags & Snapshot::kFlagDirtyOrtho;
228
229    sp<Snapshot> current = mSnapshot;
230    sp<Snapshot> previous = mSnapshot->previous;
231
232    if (restoreOrtho) {
233        mOrthoMatrix.load(current->orthoMatrix);
234    }
235
236    if (restoreLayer) {
237        composeLayer(current, previous);
238    }
239
240    mSnapshot = previous;
241    mSaveCount--;
242
243    return restoreClip;
244}
245
246void OpenGLRenderer::composeLayer(sp<Snapshot> current, sp<Snapshot> previous) {
247    if (!current->layer) {
248        LOGE("Attempting to compose a layer that does not exist");
249        return;
250    }
251
252    // Unbind current FBO and restore previous one
253    // Most of the time, previous->fbo will be 0 to bind the default buffer
254    glBindFramebuffer(GL_FRAMEBUFFER, previous->fbo);
255
256    // Restore the clip from the previous snapshot
257    const Rect& clip = previous->clipRect;
258    glScissor(clip.left, mHeight - clip.bottom, clip.getWidth(), clip.getHeight());
259
260    Layer* layer = current->layer;
261    const Rect& rect = layer->layer;
262
263    drawTextureRect(rect.left, rect.top, rect.right, rect.bottom,
264            layer->texture, layer->alpha, layer->mode, layer->blend);
265
266    LayerSize size(rect.getWidth(), rect.getHeight());
267    // Failing to add the layer to the cache should happen only if the
268    // layer is too large
269    if (!mLayerCache.put(size, layer)) {
270        LAYER_LOGD("Deleting layer");
271
272        glDeleteFramebuffers(1, &layer->fbo);
273        glDeleteTextures(1, &layer->texture);
274
275        delete layer;
276    }
277}
278
279///////////////////////////////////////////////////////////////////////////////
280// Layers
281///////////////////////////////////////////////////////////////////////////////
282
283int OpenGLRenderer::saveLayer(float left, float top, float right, float bottom,
284        const SkPaint* p, int flags) {
285    int count = saveSnapshot();
286
287    int alpha = 255;
288    SkXfermode::Mode mode;
289
290    if (p) {
291        alpha = p->getAlpha();
292        const bool isMode = SkXfermode::IsMode(p->getXfermode(), &mode);
293        if (!isMode) {
294            // Assume SRC_OVER
295            mode = SkXfermode::kSrcOver_Mode;
296        }
297    } else {
298        mode = SkXfermode::kSrcOver_Mode;
299    }
300
301    createLayer(mSnapshot, left, top, right, bottom, alpha, mode, flags);
302
303    return count;
304}
305
306int OpenGLRenderer::saveLayerAlpha(float left, float top, float right, float bottom,
307        int alpha, int flags) {
308    int count = saveSnapshot();
309    createLayer(mSnapshot, left, top, right, bottom, alpha, SkXfermode::kSrcOver_Mode, flags);
310    return count;
311}
312
313bool OpenGLRenderer::createLayer(sp<Snapshot> snapshot, float left, float top,
314        float right, float bottom, int alpha, SkXfermode::Mode mode,int flags) {
315    LAYER_LOGD("Requesting layer %fx%f", right - left, bottom - top);
316    LAYER_LOGD("Layer cache size = %d", mLayerCache.getSize());
317
318    GLuint previousFbo = snapshot->previous.get() ? snapshot->previous->fbo : 0;
319    LayerSize size(right - left, bottom - top);
320
321    Layer* layer = mLayerCache.get(size, previousFbo);
322    if (!layer) {
323        return false;
324    }
325
326    glBindFramebuffer(GL_FRAMEBUFFER, layer->fbo);
327
328    // Clear the FBO
329    glDisable(GL_SCISSOR_TEST);
330    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
331    glClear(GL_COLOR_BUFFER_BIT);
332    glEnable(GL_SCISSOR_TEST);
333
334    // Save the layer in the snapshot
335    snapshot->flags |= Snapshot::kFlagIsLayer;
336    layer->mode = mode;
337    layer->alpha = alpha / 255.0f;
338    layer->layer.set(left, top, right, bottom);
339
340    snapshot->layer = layer;
341    snapshot->fbo = layer->fbo;
342
343    // Creates a new snapshot to draw into the FBO
344    saveSnapshot();
345    // TODO: This doesn't preserve other transformations (check Skia first)
346    mSnapshot->transform.loadTranslate(-left, -top, 0.0f);
347    mSnapshot->setClip(0.0f, 0.0f, right - left, bottom - top);
348    mSnapshot->height = bottom - top;
349    setScissorFromClip();
350
351    mSnapshot->flags = Snapshot::kFlagDirtyOrtho | Snapshot::kFlagClipSet;
352    mSnapshot->orthoMatrix.load(mOrthoMatrix);
353
354    // Change the ortho projection
355    mOrthoMatrix.loadOrtho(0.0f, right - left, bottom - top, 0.0f, 0.0f, 1.0f);
356
357    return true;
358}
359
360///////////////////////////////////////////////////////////////////////////////
361// Transforms
362///////////////////////////////////////////////////////////////////////////////
363
364void OpenGLRenderer::translate(float dx, float dy) {
365    mSnapshot->transform.translate(dx, dy, 0.0f);
366}
367
368void OpenGLRenderer::rotate(float degrees) {
369    mSnapshot->transform.rotate(degrees, 0.0f, 0.0f, 1.0f);
370}
371
372void OpenGLRenderer::scale(float sx, float sy) {
373    mSnapshot->transform.scale(sx, sy, 1.0f);
374}
375
376void OpenGLRenderer::setMatrix(SkMatrix* matrix) {
377    mSnapshot->transform.load(*matrix);
378}
379
380void OpenGLRenderer::getMatrix(SkMatrix* matrix) {
381    mSnapshot->transform.copyTo(*matrix);
382}
383
384void OpenGLRenderer::concatMatrix(SkMatrix* matrix) {
385    mat4 m(*matrix);
386    mSnapshot->transform.multiply(m);
387}
388
389///////////////////////////////////////////////////////////////////////////////
390// Clipping
391///////////////////////////////////////////////////////////////////////////////
392
393void OpenGLRenderer::setScissorFromClip() {
394    const Rect& clip = mSnapshot->clipRect;
395    glScissor(clip.left, mSnapshot->height - clip.bottom, clip.getWidth(), clip.getHeight());
396}
397
398const Rect& OpenGLRenderer::getClipBounds() {
399    return mSnapshot->getLocalClip();
400}
401
402bool OpenGLRenderer::quickReject(float left, float top, float right, float bottom) {
403    Rect r(left, top, right, bottom);
404    mSnapshot->transform.mapRect(r);
405    return !mSnapshot->clipRect.intersects(r);
406}
407
408bool OpenGLRenderer::clipRect(float left, float top, float right, float bottom, SkRegion::Op op) {
409    bool clipped = mSnapshot->clip(left, top, right, bottom, op);
410    if (clipped) {
411        setScissorFromClip();
412    }
413    return !mSnapshot->clipRect.isEmpty();
414}
415
416///////////////////////////////////////////////////////////////////////////////
417// Drawing
418///////////////////////////////////////////////////////////////////////////////
419
420void OpenGLRenderer::drawBitmap(SkBitmap* bitmap, float left, float top, const SkPaint* paint) {
421    const float right = left + bitmap->width();
422    const float bottom = top + bitmap->height();
423
424    if (quickReject(left, top, right, bottom)) {
425        return;
426    }
427
428    const Texture* texture = mTextureCache.get(bitmap);
429    drawTextureRect(left, top, right, bottom, texture, paint);
430}
431
432void OpenGLRenderer::drawBitmap(SkBitmap* bitmap, const SkMatrix* matrix, const SkPaint* paint) {
433    Rect r(0.0f, 0.0f, bitmap->width(), bitmap->height());
434    const mat4 transform(*matrix);
435    transform.mapRect(r);
436
437    if (quickReject(r.left, r.top, r.right, r.bottom)) {
438        return;
439    }
440
441    const Texture* texture = mTextureCache.get(bitmap);
442    drawTextureRect(r.left, r.top, r.right, r.bottom, texture, paint);
443}
444
445void OpenGLRenderer::drawBitmap(SkBitmap* bitmap,
446         float srcLeft, float srcTop, float srcRight, float srcBottom,
447         float dstLeft, float dstTop, float dstRight, float dstBottom,
448         const SkPaint* paint) {
449    if (quickReject(dstLeft, dstTop, dstRight, dstBottom)) {
450        return;
451    }
452
453    const Texture* texture = mTextureCache.get(bitmap);
454
455    const float width = texture->width;
456    const float height = texture->height;
457
458    const float u1 = srcLeft / width;
459    const float v1 = srcTop / height;
460    const float u2 = srcRight / width;
461    const float v2 = srcBottom / height;
462
463    // TODO: Do this in the shader
464    resetDrawTextureTexCoords(u1, v1, u2, v2);
465
466    drawTextureRect(dstLeft, dstTop, dstRight, dstBottom, texture, paint);
467
468    resetDrawTextureTexCoords(0.0f, 0.0f, 1.0f, 1.0f);
469}
470
471void OpenGLRenderer::drawPatch(SkBitmap* bitmap, Res_png_9patch* patch,
472        float left, float top, float right, float bottom, const SkPaint* paint) {
473    if (quickReject(left, top, right, bottom)) {
474        return;
475    }
476
477    const Texture* texture = mTextureCache.get(bitmap);
478
479    int alpha;
480    SkXfermode::Mode mode;
481    getAlphaAndMode(paint, &alpha, &mode);
482
483    Patch* mesh = mPatchCache.get(patch);
484    mesh->updateVertices(bitmap, left, top, right, bottom,
485            &patch->xDivs[0], &patch->yDivs[0], patch->numXDivs, patch->numYDivs);
486
487    // Specify right and bottom as +1.0f from left/top to prevent scaling since the
488    // patch mesh already defines the final size
489    drawTextureMesh(left, top, left + 1.0f, top + 1.0f, texture->id, alpha / 255.0f,
490            mode, texture->blend, &mesh->vertices[0].position[0],
491            &mesh->vertices[0].texture[0], mesh->indices, mesh->indicesCount);
492}
493
494void OpenGLRenderer::drawColor(int color, SkXfermode::Mode mode) {
495    const Rect& clip = mSnapshot->clipRect;
496    drawColorRect(clip.left, clip.top, clip.right, clip.bottom, color, mode, true);
497}
498
499void OpenGLRenderer::drawRect(float left, float top, float right, float bottom, const SkPaint* p) {
500    if (quickReject(left, top, right, bottom)) {
501        return;
502    }
503
504    SkXfermode::Mode mode;
505
506    const bool isMode = SkXfermode::IsMode(p->getXfermode(), &mode);
507    if (!isMode) {
508        // Assume SRC_OVER
509        mode = SkXfermode::kSrcOver_Mode;
510    }
511
512    // Skia draws using the color's alpha channel if < 255
513    // Otherwise, it uses the paint's alpha
514    int color = p->getColor();
515    if (((color >> 24) & 0xff) == 255) {
516        color |= p->getAlpha() << 24;
517    }
518
519    drawColorRect(left, top, right, bottom, color, mode);
520}
521
522void OpenGLRenderer::drawText(const char* text, int bytesCount, int count,
523        float x, float y, SkPaint* paint) {
524    if (text == NULL || count == 0 || (paint->getAlpha() == 0 && paint->getXfermode() == NULL)) {
525        return;
526    }
527
528    float length;
529    switch (paint->getTextAlign()) {
530        case SkPaint::kCenter_Align:
531            length = paint->measureText(text, bytesCount);
532            x -= length / 2.0f;
533            break;
534        case SkPaint::kRight_Align:
535            length = paint->measureText(text, bytesCount);
536            x -= length;
537            break;
538        default:
539            break;
540    }
541
542    int alpha;
543    SkXfermode::Mode mode;
544    getAlphaAndMode(paint, &alpha, &mode);
545
546    uint32_t color = paint->getColor();
547    const GLfloat a = alpha / 255.0f;
548    const GLfloat r = a * ((color >> 16) & 0xFF) / 255.0f;
549    const GLfloat g = a * ((color >>  8) & 0xFF) / 255.0f;
550    const GLfloat b = a * ((color      ) & 0xFF) / 255.0f;
551
552    mModelView.loadIdentity();
553
554    GLuint textureUnit = 0;
555
556    ProgramDescription description;
557    description.hasTexture = true;
558    description.hasAlpha8Texture = true;
559    if (mShader) {
560        mShader->describe(description, mExtensions);
561    }
562
563    useProgram(mProgramCache.get(description));
564    mCurrentProgram->set(mOrthoMatrix, mModelView, mSnapshot->transform);
565
566    chooseBlending(true, mode);
567    bindTexture(mFontRenderer.getTexture(), GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE, textureUnit);
568    glUniform1i(mCurrentProgram->getUniform("sampler"), textureUnit);
569
570    int texCoordsSlot = mCurrentProgram->getAttrib("texCoords");
571    glEnableVertexAttribArray(texCoordsSlot);
572
573    // Always premultiplied
574    glUniform4f(mCurrentProgram->color, r, g, b, a);
575
576    textureUnit++;
577    // Setup attributes and uniforms required by the shaders
578    if (mShader) {
579        mShader->setupProgram(mCurrentProgram, mModelView, *mSnapshot, &textureUnit);
580    }
581
582    // TODO: Implement scale properly
583    const Rect& clip = mSnapshot->getLocalClip();
584    mFontRenderer.setFont(paint, SkTypeface::UniqueID(paint->getTypeface()), paint->getTextSize());
585    mFontRenderer.renderText(paint, &clip, text, 0, bytesCount, count, x, y);
586
587    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
588    glDisableVertexAttribArray(texCoordsSlot);
589}
590
591///////////////////////////////////////////////////////////////////////////////
592// Shaders
593///////////////////////////////////////////////////////////////////////////////
594
595void OpenGLRenderer::resetShader() {
596    mShader = NULL;
597}
598
599void OpenGLRenderer::setupShader(SkiaShader* shader) {
600    mShader = shader;
601    if (mShader) {
602        mShader->set(&mTextureCache, &mGradientCache);
603    }
604}
605
606///////////////////////////////////////////////////////////////////////////////
607// Drawing implementation
608///////////////////////////////////////////////////////////////////////////////
609
610void OpenGLRenderer::drawColorRect(float left, float top, float right, float bottom,
611        int color, SkXfermode::Mode mode, bool ignoreTransform) {
612    // If a shader is set, preserve only the alpha
613    if (mShader) {
614        color |= 0x00ffffff;
615    }
616
617    // Render using pre-multiplied alpha
618    const int alpha = (color >> 24) & 0xFF;
619    const GLfloat a = alpha / 255.0f;
620    const GLfloat r = a * ((color >> 16) & 0xFF) / 255.0f;
621    const GLfloat g = a * ((color >>  8) & 0xFF) / 255.0f;
622    const GLfloat b = a * ((color      ) & 0xFF) / 255.0f;
623
624    GLuint textureUnit = 0;
625
626    // Setup the blending mode
627    chooseBlending(alpha < 255 || (mShader && mShader->blend()), mode);
628
629    // Describe the required shaders
630    ProgramDescription description;
631    if (mShader) {
632        mShader->describe(description, mExtensions);
633    }
634
635    // Build and use the appropriate shader
636    useProgram(mProgramCache.get(description));
637
638    // Setup attributes
639    glVertexAttribPointer(mCurrentProgram->position, 2, GL_FLOAT, GL_FALSE,
640            gMeshStride, &mMeshVertices[0].position[0]);
641
642    // Setup uniforms
643    mModelView.loadTranslate(left, top, 0.0f);
644    mModelView.scale(right - left, bottom - top, 1.0f);
645    if (!ignoreTransform) {
646        mCurrentProgram->set(mOrthoMatrix, mModelView, mSnapshot->transform);
647    } else {
648        mat4 identity;
649        mCurrentProgram->set(mOrthoMatrix, mModelView, identity);
650    }
651    glUniform4f(mCurrentProgram->color, r, g, b, a);
652
653    // Setup attributes and uniforms required by the shaders
654    if (mShader) {
655        mShader->setupProgram(mCurrentProgram, mModelView, *mSnapshot, &textureUnit);
656    }
657
658    // Draw the mesh
659    glDrawArrays(GL_TRIANGLE_STRIP, 0, gMeshCount);
660}
661
662void OpenGLRenderer::drawTextureRect(float left, float top, float right, float bottom,
663        const Texture* texture, const SkPaint* paint) {
664    int alpha;
665    SkXfermode::Mode mode;
666    getAlphaAndMode(paint, &alpha, &mode);
667
668    drawTextureMesh(left, top, right, bottom, texture->id, alpha / 255.0f, mode, texture->blend,
669            &mMeshVertices[0].position[0], &mMeshVertices[0].texture[0], NULL);
670}
671
672void OpenGLRenderer::drawTextureRect(float left, float top, float right, float bottom,
673        GLuint texture, float alpha, SkXfermode::Mode mode, bool blend) {
674    drawTextureMesh(left, top, right, bottom, texture, alpha, mode, blend,
675            &mMeshVertices[0].position[0], &mMeshVertices[0].texture[0], NULL);
676}
677
678void OpenGLRenderer::drawTextureMesh(float left, float top, float right, float bottom,
679        GLuint texture, float alpha, SkXfermode::Mode mode, bool blend,
680        GLvoid* vertices, GLvoid* texCoords, GLvoid* indices, GLsizei elementsCount) {
681    ProgramDescription description;
682    description.hasTexture = true;
683
684    mModelView.loadTranslate(left, top, 0.0f);
685    mModelView.scale(right - left, bottom - top, 1.0f);
686
687    useProgram(mProgramCache.get(description));
688    mCurrentProgram->set(mOrthoMatrix, mModelView, mSnapshot->transform);
689
690    chooseBlending(blend || alpha < 1.0f, mode);
691
692    // Texture
693    bindTexture(texture, GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE, 0);
694    glUniform1i(mCurrentProgram->getUniform("sampler"), 0);
695
696    // Always premultiplied
697    glUniform4f(mCurrentProgram->color, alpha, alpha, alpha, alpha);
698
699    // Mesh
700    int texCoordsSlot = mCurrentProgram->getAttrib("texCoords");
701    glEnableVertexAttribArray(texCoordsSlot);
702    glVertexAttribPointer(mCurrentProgram->position, 2, GL_FLOAT, GL_FALSE,
703            gMeshStride, vertices);
704    glVertexAttribPointer(texCoordsSlot, 2, GL_FLOAT, GL_FALSE, gMeshStride, texCoords);
705
706    if (!indices) {
707        glDrawArrays(GL_TRIANGLE_STRIP, 0, gMeshCount);
708    } else {
709        glDrawElements(GL_TRIANGLES, elementsCount, GL_UNSIGNED_SHORT, indices);
710    }
711    glDisableVertexAttribArray(texCoordsSlot);
712}
713
714void OpenGLRenderer::chooseBlending(bool blend, SkXfermode::Mode mode, bool isPremultiplied) {
715    // In theory we should not blend if the mode is Src, but it's rare enough
716    // that it's not worth it
717    blend = blend || mode != SkXfermode::kSrcOver_Mode;
718    if (blend) {
719        if (!mBlend) {
720            glEnable(GL_BLEND);
721        }
722
723        GLenum sourceMode = gBlends[mode].src;
724        GLenum destMode = gBlends[mode].dst;
725        if (!isPremultiplied && sourceMode == GL_ONE) {
726            sourceMode = GL_SRC_ALPHA;
727        }
728
729        if (sourceMode != mLastSrcMode || destMode != mLastDstMode) {
730            glBlendFunc(sourceMode, destMode);
731            mLastSrcMode = sourceMode;
732            mLastDstMode = destMode;
733        }
734    } else if (mBlend) {
735        glDisable(GL_BLEND);
736    }
737    mBlend = blend;
738}
739
740bool OpenGLRenderer::useProgram(Program* program) {
741    if (!program->isInUse()) {
742        if (mCurrentProgram != NULL) mCurrentProgram->remove();
743        program->use();
744        mCurrentProgram = program;
745        return false;
746    }
747    return true;
748}
749
750void OpenGLRenderer::resetDrawTextureTexCoords(float u1, float v1, float u2, float v2) {
751    TextureVertex* v = &mMeshVertices[0];
752    TextureVertex::setUV(v++, u1, v1);
753    TextureVertex::setUV(v++, u2, v1);
754    TextureVertex::setUV(v++, u1, v2);
755    TextureVertex::setUV(v++, u2, v2);
756}
757
758void OpenGLRenderer::getAlphaAndMode(const SkPaint* paint, int* alpha, SkXfermode::Mode* mode) {
759    if (paint) {
760        const bool isMode = SkXfermode::IsMode(paint->getXfermode(), mode);
761        if (!isMode) {
762            // Assume SRC_OVER
763            *mode = SkXfermode::kSrcOver_Mode;
764        }
765
766        // Skia draws using the color's alpha channel if < 255
767        // Otherwise, it uses the paint's alpha
768        int color = paint->getColor();
769        *alpha = (color >> 24) & 0xFF;
770        if (*alpha == 255) {
771            *alpha = paint->getAlpha();
772        }
773    } else {
774        *mode = SkXfermode::kSrcOver_Mode;
775        *alpha = 255;
776    }
777}
778
779void OpenGLRenderer::bindTexture(GLuint texture, GLenum wrapS, GLenum wrapT, GLuint textureUnit) {
780    glActiveTexture(gTextureUnits[textureUnit]);
781    glBindTexture(GL_TEXTURE_2D, texture);
782    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrapS);
783    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrapT);
784}
785
786}; // namespace uirenderer
787}; // namespace android
788