Archive for October, 2008

Floating-point tolerances revisited

For several years now I’ve participated in the physics tutorial session at GDC (along with Jim Van Verth, Gino van den Bergen, Erin Catto, Brian ‘Squirrel’ Eiserloh, and Marq Singer). One section I’ve covered in some detail is robustness and within this area I’ve stressed (amongst other things) the importance of distinguishing between absolute and relative tolerances when performing comparisons of floating-point numbers.

I won’t go into details about why you would want to care about how your floating-point numbers are compared. (Detailed information can be found in part in my GDC presentation slides and in much more depth in my book.) Here I will assume you already know why you care, and I will just note that absolute and relative tolerances are tested as Read the rest of this entry »

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Order your graphics draw calls around!

A while ago a local developer (hi Rick) asked about what I thought was the best way of ordering draw calls for sending to the graphics chip. As the topic came up again in a discussion at work recently, I thought I’d share my thoughts about what I think is the best approach these days. Read the rest of this entry »

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