ios - 如何在普通的iOS应用程序(基于UIWindow)中使用GPU加速的SkCanvas？

是否可以将OpenGL视图添加到UIWindow并使用Skia进行绘制？

我找到了一个示例，在其中初始化了这样的视图:

 - (void)initialize {
     CAEAGLLayer* layer = (CAEAGLLayer*)self.layer;

     layer.opaque = NO;
     layer.drawableProperties = @{kEAGLDrawablePropertyRetainedBacking: @(NO),
                                  kEAGLDrawablePropertyColorFormat: kEAGLColorFormatRGBA8};

     self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
      if (!self.context || ![EAGLContext setCurrentContext:self.context])
         NSLog(@"Cannot create EAGLContext!");

     GLuint framebuffer;
     GLuint renderbuffer;
     glGenFramebuffers(1, &framebuffer);
     glGenRenderbuffers(1, &renderbuffer);
     glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
     glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);

     [self.context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer*)layer];
     glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);

     GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
     if (status != GL_FRAMEBUFFER_COMPLETE)
         NSLog(@"Failed to make complete frame buffer: %x", status);

     CADisplayLink* displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(drawFrame:)];
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
}

- (void)drawFrame:(CADisplayLink*)sender {
    glClearColor(1.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    [self.context presentRenderbuffer:GL_RENDERBUFFER];
}

绘制了红色背景，但我无法使Skia与此视图一起使用。

我的skia代码:

const GrGLInterface* glInterface = GrGLCreateNativeInterface();
NSAssert(glInterface->validate(), nil);

GrContextOptions contextOptions;
GrContext* grContext = GrContext::Create(kOpenGL_GrBackend, (intptr_t)glInterface, contextOptions);
sk_sp<SkColorSpace> colorSpace = SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named);

GrBackendRenderTargetDesc grBackendRenderTargetDesc;

// This is GLuint framebuffer value from view setup code above.
grBackendRenderTargetDesc.fRenderTargetHandle = self.framebufferID;

grBackendRenderTargetDesc.fWidth = self.rboWidth;
grBackendRenderTargetDesc.fHeight = self.rboHeight;
grBackendRenderTargetDesc.fConfig = kRGBA_8888_GrPixelConfig;
grBackendRenderTargetDesc.fOrigin = kTopLeft_GrSurfaceOrigin;
grBackendRenderTargetDesc.fSampleCnt = 0;
grBackendRenderTargetDesc.fStencilBits = 0;

SkSurfaceProps skSurfaceProps(0, kUnknown_SkPixelGeometry);
sk_sp<SkSurface> skSurface = SkSurface::MakeFromBackendRenderTarget(grContext, grBackendRenderTargetDesc, &skSurfaceProps);

if (skSurface)
{
    skCanvas = skSurface->getCanvas();

    SkPaint paint;
    paint.setColor(SK_ColorGREEN);
    skCanvas->drawPaint(paint);
}

当我在[self.context presentRenderbuffer:GL_RENDERBUFFER]之前的[... drawFrame:]中放置画布绘制代码时，它不会绘制任何内容。

我想念什么？如何将SkSurface / SkCanvas与给定的EAGLContext链接，如何调用Skia绘图代码以使其正常工作？

最佳答案

当我打电话时它按预期工作

skSurface->prepareForExternalIO()

毕竟，Skia绘图代码是在我致电之前

[self.context presentRenderbuffer:GL_RENDERBUFFER];

关于ios - 如何在普通的iOS应用程序(基于UIWindow)中使用GPU加速的SkCanvas？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/42096415/