SkiaOpenGLReadback.cpp revision c4fbada76aa840105553b2c2bce2204e673d2983 
1/*
2 * Copyright (C) 2016 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 "SkiaOpenGLReadback.h"
18
19#include "Matrix.h"
20#include "Properties.h"
21#include <SkCanvas.h>
22#include <SkSurface.h>
23#include <gl/GrGLInterface.h>
24#include <gl/GrGLTypes.h>
25#include <GLES2/gl2.h>
26#include <GLES2/gl2ext.h>
27
28using namespace android::uirenderer::renderthread;
29
30namespace android {
31namespace uirenderer {
32namespace skiapipeline {
33
34CopyResult SkiaOpenGLReadback::copyImageInto(EGLImageKHR eglImage, const Matrix4& imgTransform,
35        int imgWidth, int imgHeight, const Rect& srcRect, SkBitmap* bitmap) {
36
37    GLuint sourceTexId;
38    glGenTextures(1, &sourceTexId);
39    glBindTexture(GL_TEXTURE_EXTERNAL_OES, sourceTexId);
40    glEGLImageTargetTexture2DOES(GL_TEXTURE_EXTERNAL_OES, eglImage);
41
42    sk_sp<GrContext> grContext = sk_ref_sp(mRenderThread.getGrContext());
43    if (Properties::getRenderPipelineType() == RenderPipelineType::SkiaVulkan) {
44        sk_sp<const GrGLInterface> glInterface(GrGLCreateNativeInterface());
45        LOG_ALWAYS_FATAL_IF(!glInterface.get());
46        grContext.reset(GrContext::Create(GrBackend::kOpenGL_GrBackend,
47                (GrBackendContext)glInterface.get()));
48    } else {
49        grContext->resetContext();
50    }
51
52    GrGLTextureInfo externalTexture;
53    externalTexture.fTarget = GL_TEXTURE_EXTERNAL_OES;
54    externalTexture.fID = sourceTexId;
55
56    GrBackendTextureDesc textureDescription;
57    textureDescription.fWidth = imgWidth;
58    textureDescription.fHeight = imgHeight;
59    textureDescription.fConfig = kRGBA_8888_GrPixelConfig;
60    textureDescription.fOrigin = kTopLeft_GrSurfaceOrigin;
61    textureDescription.fTextureHandle = reinterpret_cast<GrBackendObject>(&externalTexture);
62
63    CopyResult copyResult = CopyResult::UnknownError;
64    sk_sp<SkImage> image(SkImage::MakeFromAdoptedTexture(grContext.get(), textureDescription));
65    if (image) {
66        SkAutoLockPixels alp(*bitmap);
67
68        // convert to Skia data structures
69        const SkRect bufferRect = SkRect::MakeIWH(imgWidth, imgHeight);
70        SkRect skiaSrcRect = srcRect.toSkRect();
71        SkMatrix textureMatrix;
72        imgTransform.copyTo(textureMatrix);
73
74        // remove the y-flip applied to the matrix so that we can scale the srcRect.
75        // This flip is not needed as we specify the origin of the texture when we
76        // wrap it as an SkImage.
77        SkMatrix yFlip = SkMatrix::MakeScale(1, -1);
78        yFlip.postTranslate(0,1);
79        textureMatrix.preConcat(yFlip);
80
81        // copy the entire src if the rect is empty
82        if (skiaSrcRect.isEmpty()) {
83            skiaSrcRect = bufferRect;
84        }
85
86        // since the y-flip has been removed we can simply scale & translate
87        // the source rectangle
88        textureMatrix.mapRect(&skiaSrcRect);
89
90        if (skiaSrcRect.intersect(bufferRect)) {
91            SkPoint srcOrigin = SkPoint::Make(skiaSrcRect.fLeft, skiaSrcRect.fTop);
92
93            // if we need to scale the result we must render to an offscreen buffer
94            if (bitmap->width() != skiaSrcRect.width()
95                    || bitmap->height() != skiaSrcRect.height()) {
96                sk_sp<SkSurface> scaledSurface = SkSurface::MakeRenderTarget(
97                        grContext.get(), SkBudgeted::kYes, bitmap->info());
98                SkPaint paint;
99                paint.setBlendMode(SkBlendMode::kSrc);
100                scaledSurface->getCanvas()->drawImageRect(image, skiaSrcRect,
101                        SkRect::MakeWH(bitmap->width(), bitmap->height()), &paint);
102                image = scaledSurface->makeImageSnapshot();
103                srcOrigin.set(0,0);
104            }
105
106            if (image->readPixels(bitmap->info(), bitmap->getPixels(), bitmap->rowBytes(),
107                                  srcOrigin.fX, srcOrigin.fY)) {
108                copyResult = CopyResult::Success;
109            }
110        }
111    }
112
113    // make sure that we have deleted the texture (in the SkImage) before we
114    // destroy the EGLImage that it was created from
115    image.reset();
116    return copyResult;
117}
118
119} /* namespace skiapipeline */
120} /* namespace uirenderer */
121} /* namespace android */
122