Some math I did ... (not 100% verified, but looks like it works) n = near f = far z = depth buffer Z-value EZ = eye Z value LZ = depth buffer Z-value remapped to a linear [0..1] range (near plane to far plane) LZ2 = depth buffer Z-value remapped to a linear [0..1] range (eye to far plane) DX: EZ = (n * f) / (f - z * (f - n)) LZ = (eyeZ - n) / (f - n) = z / (f - z * (f - n)) LZ2 = eyeZ / f = n / (f - z * (f - n)) GL: EZ = (2 * n * f) / (f + n - z * (f - n)) LZ = (eyeZ - n) / (f - n) = n * (z + 1.0) / (f + n - z * (f - n)) LZ2 = eyeZ / f = (2 * n) / (f + n - z * (f - n)) LZ2 in two instructions: LZ2 = 1.0 / (c0 * z + c1) DX: c1 = f / n c0 = 1.0 - c1 GL: c0 = (1 - f / n) / 2 c1 = (1 + f / n) / 2 ------------------- http://www.humus.ca
原文：http://blog.csdn.net/claien/article/details/43850799