curving projectiles and center of mass, not the usual ?

RolandofGilead · 2002-12-23T10:29:36

1) I''m doing a game with some 2d space ships firing some beams, and it would be much easier to treat them as straight lines, but the ships can be accelerating and the beams can be spun around. Is there a fast, easy way to deform the beam. Yes, linear velocity does equal radius times angular velocity. There are also projectile weapons, but they travel at the same speed as the beams, so if the beams are treated as straight lines there may be instances when things won''t look right, like if a ship is *accelerating* forward while firing a beam and projectile weapon to the side, the two won''t curve the same if I treat the beams as straight lines. Any suggestions for how to alleviate this problem? 2) Say we have a 3d model(a bunch of points that define the outer surface of an object), if it has uniform density, under what conditions will its center of mass not be the average of the vertices? Would it work if you took the midpoint of every polygon and averaged them out, provided that every polygon has equal area? And I don''t know why this idea popped into my head, but would it be accurate to average out the position of all the midpoints of lines created by drawing a line between each vertex and all other vertices? Although I''m not sure if duplicate lines should be counted and/or if one should discard all lines that are already formed with the vertex.

Math and Physics Programming

Started by RolandofGilead December 16, 2002 03:30 AM

13 comments, last by RolandofGilead 22 years, 2 months ago

rmsgrey

153

December 18, 2002 11:08 AM

quote:
Original post by Tron3k
1) If you mean that the beams are curving back because they are shot while you are accelerating, they wouldn''t curve back if they are light/laser beams because according to Einstein the speed of light is constant to any observer.

Actually, according to Einstein, the speed of light is constant to any observer in a fixed reference frame (ie in free fall). If your acceleration doesn''t match the local gravity, then you''ll get different results from people who are in free fall.

Just a little nit-pick to brighten my day

Metorical

580

December 18, 2002 11:31 AM

rmsgrey: I''m pretty sure the speed of light is constant throughout all frames.

SoulSpectre

169

December 19, 2002 05:16 AM

The answer you want is simple:

Have your beam weapon code spit out points (like bullets) with velocity. Now simply draw your beam connecting these points. You can further enhance this by applying a spline curve to these points.

TerranFury

142

December 21, 2002 12:22 PM

SoulSpecre is 100% correct. Model your stream as a whole bunch of line segments connecting individual particles and be done with it.

I guess your weapon is a scifi version of greek fire, substituting superheated plasma for burning oil?

jediknight219

122

December 23, 2002 10:29 AM

Oh this sounds interesting. Esp. if you modify the damage caused based on the amount of the beam the enemy ship is exposed to, along with the "density" of the beam that the ship gets hit with. Remember that a curved beam would lose density as it gets further out and expands. Should be easy to figure out density using SoulSpectre''s method. The density would be proportional to the distance between the "bullet" points.

Aaargh! Everyone save your workspaces before your program locks up your computer!

curving projectiles and center of mass, not the usual ?

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curving projectiles and center of mass, not the usual ?

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