[英]OpenGL ES 2.0 textures for retina display?
我有一个GLKView,我尝试在其中绘制几个多维数据集,并从视图中创建纹理并将其映射到多维数据集。 但是,当我在视网膜设备上启动该应用程序时,纹理的大小正确,但看起来很糟糕。 我试图将GLKView的contentScaleFactor设置为主屏幕的比例-无济于事。 我还尝试将缓冲区的尺寸乘以比例尺,从而使纹理看起来清晰,但仅为原始尺寸的1/4 ...
事不宜迟,我可以向您介绍我所做的事情(没有上面指出的乘法):
GLKView
- (void)setupGL {
UIScreen *mainScreen = [UIScreen mainScreen];
const CGFloat scale = mainScreen.scale;
self.contentScaleFactor = scale;
self.layer.contentsScale = scale;
glGenFramebuffers(1, &defaultFrameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, defaultFrameBuffer);
glGenRenderbuffers(1, &depthBuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthBuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, self.bounds.size.width, self.bounds.size.height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthBuffer);
glGenRenderbuffers(1, &colorBuffer);
glBindRenderbuffer(GL_RENDERBUFFER, colorBuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA4, self.bounds.size.width, self.bounds.size.height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ARRAY, GL_RENDERBUFFER, colorBuffer);
glEnable(GL_DEPTH_TEST);
}
在这里我加载纹理
// make space for an RGBA image of the view
GLubyte *pixelBuffer = (GLubyte *)malloc(
4 *
cV.bounds.size.width *
cV.bounds.size.height);
// create a suitable CoreGraphics context
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context =
CGBitmapContextCreate(pixelBuffer,
cV.bounds.size.width, cV.bounds.size.height,
8, 4*cV.bounds.size.width,
colourSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colourSpace);
// draw the view to the buffer
[cV.layer renderInContext:context];
// upload to OpenGL
glTexImage2D(GL_TEXTURE_2D, 0,
GL_RGBA,
cV.bounds.size.width, cV.bounds.size.height, 0,
GL_RGBA, GL_UNSIGNED_BYTE, pixelBuffer);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
这个问题的答案可以在这里找到
我基本上所做的就是将纹理和缓冲区乘以屏幕的比例因子,因为这只能产生大小的1/4的纹理,所以我也必须将上下文乘以比例因子
CGContextScaleCTM(context, scaleFactor, scaleFactor);
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