02 2012 档案

摘要：from cywater：传统Z-Test其实是发生在PS之后的，因此仅仅依靠Z-Test并不能加快多少渲染速度。而EZC则发生在光栅化之后，调用PS之前。EZC会提前对深度进行比较，如果测试通过(Z-Func)，则执行PS，否则跳过此片段/像素(fragment/pixel)。不过要注意的是，在PS中不能修改深度值，否则EZC会被禁用。这样，在整个流水线阶段，深度比较发生了2次，一次是EZC，一次是传统Z-Test（注: 区别可能在于EZC无法写入深度）。除了利用EZC帮助传统Z-Test加速之外（硬件自动调用，我称其为隐式用法），目前还有2个显示引申用法：一个类似于Deferred Sha 阅读全文

摘要：Depth Buffer 1、Learning to Love your Z-bufferIntroductionOne of the more common OpenGL programming problems that I see concerns the poor precision of the Z buffer.Many of the early 3D adaptors for the PC have a 16 bit Z buffer, some others have 24 bits - and the very best have 32 bits. If you are lu 阅读全文

摘要：1、It is expected that graphics hardware will have a small number of fixed vector locations for passing vertex inputs. Therefore, the OpenGL Shading language defines each non-matrix input variable as taking up one such vector location. There is an implementation dependent limit on the number of locat 阅读全文