3

我在我的 OpenGL ES iOS 应用程序中添加了多重采样抗锯齿，但我注意到一些奇怪的事情。

我按照这里的步骤操作： https ://developer.apple.com/library/ios/documentation/3ddrawing/conceptual/opengles_programmingguide/WorkingwithEAGLContexts/WorkingwithEAGLContexts.html

  1. 抗锯齿在模拟器中效果很好。在启用和禁用它时（在 iOS 模拟器中），我注意到线锯齿的主要区别。不过，它似乎不适用于我的 iPad mini。线条仍然是锯齿状的。有任何想法吗？

哎呀！

  1. 实施 MSAA 后，在 OpenGL ES 分析器中，我注意到这种情况发生了很多：“未优化的 MSAA 解析”

下面的两行似乎修复了“未优化的 MSAA Resolve”，但颜色附件丢弃似乎使我的行不再是黑色并且它们消失了：

const GLenum discards[]  = {GL_COLOR_ATTACHMENT0_OES, GL_DEPTH_ATTACHMENT_OES};
glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 2, discards);

MSAA 创建：

// Generate IDs for a framebuffer object and a color renderbuffer
glGenFramebuffersOES(1, &viewFramebuffer);
glGenRenderbuffersOES(1, &viewRenderbuffer);

glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
// This call associates the storage for the current render buffer with the EAGLDrawable (our CAEAGLLayer)
// allowing us to draw into a buffer that will later be rendered to screen wherever the layer is (which corresponds with our view).
[context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(id<EAGLDrawable>)self.layer];
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);

glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);

// For this sample, we also need a depth buffer, so we'll create and attach one via another renderbuffer.
glGenRenderbuffersOES(1, &depthRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);

if(isMsaaEnabled) {
    glGenFramebuffersOES(1, &msaaFramebuffer);
    glGenRenderbuffersOES(1, &msaaRenderbuffer);

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, msaaFramebuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, msaaRenderbuffer);

    // 4X MSAA
    glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER_OES, 4, GL_RGBA8_OES, backingWidth, backingHeight);
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, msaaRenderbuffer);

    glGenRenderbuffersOES(1, &msaaDepthbuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, msaaDepthbuffer);
    glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER_OES, 4, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, msaaDepthbuffer);
    if (glCheckFramebufferStatus(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES)
    {
        NSLog(@"Failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER_OES));
        return NO;
    }
}

解决：

if (isMsaaEnabled) {
    glBindFramebufferOES(GL_READ_FRAMEBUFFER_APPLE, msaaFramebuffer);
    glBindFramebufferOES(GL_DRAW_FRAMEBUFFER_APPLE, viewFramebuffer);
    glResolveMultisampleFramebufferAPPLE();

    const GLenum discards[]  = {GL_COLOR_ATTACHMENT0_OES, GL_DEPTH_ATTACHMENT_OES};
    glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 2, discards);
}
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
4

0 回答 0