Here''s something you all are prolly familiar with:

// runs every frame

CurrentFrame = timeGetTime() * 0.001f;
DeltaFrame = CurrentFrame - LastFrame;
LastFrame = CurrentFrame;

Then you multiply DeltaFrame by the addition to the position of different objects, like the player''s, bullets'', etc. Recently I''ve been implementing a bullets-player collision system, that has to work well with high speeds as the bullets travel extremely fast. This means that they can jump over the player if their velocity is fast enough (bullet being on one side of the player, and in the next frame on his other side). So I developed a system that creates a line from the bullet to where it will be in the next frame. This means that this line''s size is basically the speed of the bullet. Then I create an amount of points on the line that depend on it''s own length. After that I check each of those points versus the player, that way the bullet can never go ''through'' the player. If the shooter was standing still and kept on shooting the size of the lines of the bullets kept varying, even though no paramter to the line''s size changed. (the shooter stood still, kept the same angle, and the bullet''s velocity never changed as the shooter did not change weapons). So the only paramter to change the size of the line was DeltaFrame. Infact it changed so much that sometimes the size of the line was so close to 0 that only one point was created on the line, and then that specific bullet could infact go through the player. It does make sense for DeltaFrame to change as the FPS varies slightly according to changes on the screen etc. How about this: You make a moving average for the DeltaFrame: Meaning you save the last 10 ''DeltaFrames'' in an array and then put an average of all 10 cells into the DeltaFrame variable that you''re actually gonna use. This smooths everything out, from the movement of the player to the bullets and everything else that uses DeltaFrame, as the changes to that variable are not so drastic anymore. But it still changes according to what''s happening on the screen as it should (since 10 frames is only one sixth of a second if your engine is running at 60 FPS, for example). Not only that but it completely solved my problem with the bullet-player collision detection, as the size of the line was very close to constant now, and never went through the player anymore. What do you guys think of using the moving average method for your DeltaFrame variable?

so how do people render things like bullet time?

Didn''t Quake use that method for its weapons? Trace-scanned weapons for guns and others where you dont see the projectile. And projectile type of weapons like grenades launcher where you could actually see the projectile?