wallaby Posted August 30, 2016 Share Posted August 30, 2016 Hello! I'm trying to make a projectile fire at a x / y location on the screen. Obviously, this is easy with a modern system and I'd normally use (pseudo code): ProjectileVector = OriginXY - TargetXY ProjectileVector.Normalize MissileSpeed = ProjectileVector * MaximumSpeed Normalizing the vector allows you to multiply it by your maximum missile speed and get set the proper X / Y velocity to strike the target. What I'm doing now is: target_distance_x = (player3x - target_x) / 4 target_distance_y = (player3y - target_y) / 4 I'm using / 4 to get the projectile to follow a path based on my playfield resolution. player3 is my missile sprite. (Using DPC+) This leaves me with, for example, target_distance_x = 5, target_distance_y = 3 Which is correct, but I can't just make those numbers my missile velocity because they're way too fast. I don't how if it's possible to normalize target x and y (would need fixed point numbers and division) and if it is, you'd still need to multiply those by another number to get the right velocity. If I divide the target_distance by 2 or 4 or whatever, the missile goes slower, but not to the right location. Rounding errors. How did Missile Command aim missiles? Quote Link to comment Share on other sites More sharing options...
+Random Terrain Posted August 30, 2016 Share Posted August 30, 2016 I wonder if this might help: randomterrain.com/atari-2600-memories-batari-basic-commands.html#ex_smooth_chase Quote Link to comment Share on other sites More sharing options...
wallaby Posted August 30, 2016 Author Share Posted August 30, 2016 Ah, what a great resource! That is some serious code voodoo. I've got it working now but I don't really understand it. Not that I'm complaining! I use your website all time trying to learn my way around the Atari. Thanks for creating it! Quote Link to comment Share on other sites More sharing options...
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