need help with missle code please
BlitzMax Forums/BlitzMax Programming/need help with missle code please
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| i've typed up some rough code as a place to start, and it works and looks fairly decent, but not as well as i'd like. 1. how would i get the missle to go in a straight line even on and angle, instead of doing the over 1, up 1 type thing. 2. how do i get a trail to follow the missle, regardless of the angle. as is right now it follows it from then center of origin, and when the missle rotates the trail doesn't always line up. also i'd like the trail to start at the end of the missle, and not the middle. any help would be appreciated.
'move missle to target
If missleon = 1
'create the smoke and fire trail
Local r=Rand(0,100)
If r>95
TParticles.CreateParticle(mx#+Sin(mx#),my#+Cos(my#),500,"smoke",0.01,1)
TParticles.CreateParticle(mx#+Sin(mx#),my#+Cos(my#),10,"fire",0.1,1)
EndIf
'move
If mx# < tmx# then mx#:+mxspeed#
If mx# > tmx# Then mx#:-mxspeed#
If my# < tmx# then my#:+myspeed#
If my# > tmx# Then my#:-myspeed#
If mx# = tmx# And my# = tmy# Then missleon = 0
'get the angle between missle and target
'to point the missle at the target
misslerot# = Angle360b#(mx#,my#,tmx#,tmy#)
EndIf
Function Angle360b#(x1,y1,x2,y2)
'Returns a 360 degree angle between 2 points, 0..359 degrees
'By Snarkbait, 9 Mar 2008
Return (ATan2(y2-y1,x2-x1)+450) Mod 360
End Function
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| here's some code if it helps: |
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| 1. you first need to separate the direction of travel from speed of travel based on x and y, usually dx and dy dx = cos(missileangle) dy = sin(missileangle) they are the direction of movement for one unit movement. To move an object one unit, all you you need to do is to add dx and dy to the current position: missilex = missilex+dx missiley = missiley+dy if you want to add a speed variable all you need to do is: missilex = missilex+dx*speed missiley = missiley+dy*speed If you want to change direction, all you have to do is change the angle and recalculate dx and dy. 2. the easyest way is to set the image handle to the base of the missile. but if you want to do it the more complicated way: set the handle to the center of the image. calculate the distance between the center of the image/missile to the base/tail of the missile. D = sqr((x2-x1)^2+(y2-y1)^2) or D = sqr((imagewidth/2)^2+(imageheight/2)^2) you have to do the previous only once. To find where to place the particle you need to add or subtract 180 degrees from the direction of the missile this will give you the angle of the tail of the missile. { particleangleposition = missileangle+180 px = cos(particleangleposition)* D py = sin(particleangleposition)* D } this are done everytime it changes direction/angle. particlepositionx = missilex+px particlepositiony = missiley+py and you don't need to move the particle/s only create them/it and keep on drawing them/it for a certain amount of time then delete as time passes by. I hope this helps? I posted some code in the code archives a while back: http://www.blitzmax.com/codearcs/codearcs.php?code=2045 it doesn't help for number 2 but it will give you an idea for number 1. |
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| thankyou for the help guys. parts of that stuff does seem like some different stuff i've already tried with the same results. ie. the trail is of to the side not directly under the missle. also for some strange reason the missle will only goto a certain y level and stop. this is implementing in the code that Jesse wrote. anyways thanks again for the help, and i'm gonna study the code some more and hack away at it til i get it tomorrow/today when i'm not so tired. ---------------------------------------- Edit: ok i lied i haven't gone to bed yet. i was tinkering around and got the trail to work,(looks cool btw.. big thanks for that cause it was really bugging me) what i did was my missle pic is 24 by 64 so i setimagehandel(image,12,64) px = Cos(particleangleposition)' * d py = Sin(particleangleposition)' * d i had to rem out them *d so maybe i misinterpreted the way it was supposed to be done. i can live with my pathetic way of moving the missle If mx# < tmx# Then mx#:+misslespeed# If mx# > tmx# Then mx#:-misslespeed# If my# < tmy# Then my#:+misslespeed# If my# > tmy# Then my#:-misslespeed# because in this paticular game it works fine, but im still gonna play around with that once i get some sleep and can think a little clearer |
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| sorry to bring back an old topic, but i've been playing with this some more and got it working. i had to multiply dy by (-1) to get it working though. anyway i whipped up a quick test program, so here it is. i hope it can help others out. Graphics 800,600 Global a 'angle Global x# = 400,y# = 300 'ball position Global dx# ,dy# 'x/y directions Global tx# ,ty# 'target x/y position Global movespeed# = 5.5 'how fast ball moves Global moveon = 0 'toggle on/off ball movement Global mx,my 'holders for mouse x/y position Local quit = 0 While quit = 0 Cls If moveon = 1 Then Move() DrawOval(x-5,y-5,10,10) DrawText "x: "+x,10,10 DrawText "y: "+y,10,20 DrawText "tx: "+tx,10,30 DrawText "ty: "+ty,10,40 DrawText "a: "+a,10,50 DrawText "dx: "+dx,10,70 DrawText "dy: "+dy,10,80 Flip mx = MouseX() my = MouseY() If MouseHit(1) tx = mx ty = my a = Angle360#(x,y,tx,ty) dx = Sin(a)*movespeed# dy = (Cos(a)*movespeed#)*-1 moveon = 1 EndIf If AppTerminate() Then quit = 1 If KeyDown(key_escape) Then quit = 1 FlushMouse Wend End Function Angle360#(x1,y1,x2,y2) 'Returns a 360 degree angle between 2 points, 0..359 degrees 'By Snarkbait, 9 Mar 2008 Return (ATan2(y2-y1,x2-x1)+450) Mod 360 End Function Function Move() x:+dx y:+dy If x > tx - (2+movespeed) And x < tx + (2+movespeed) Then x = tx If y > ty - (2+movespeed) And y < ty + (2+movespeed) Then y = ty If x = tx And y = ty Then moveon = 0 End Function |
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| here you go: always use cos for x and sin for y create your image pointing right always sence 0 angle is to the right and you won't go wrong. like this --> instead of like this ^ | | |
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| wow unbelieveable, no wonder i was having so much trouble with it. i must have studied your's and Yahfree's code amoung other exampels on the forums over and over again off and on over these past months trying to figure out what i was doing wrong, i could have sworn i saw cos,sin the other way around even when i picked it up again today because of one of my current projects i couldn't figure out why i needed to multiply dy by (-1) to get it to work and i studied both your codes in this thread again and still could have sworn that cos,sin were the other way around. thanks for straightening me out but gee maybe i need glasses lol. although my code above works great and actually looks really cool in both my original game that this thread was started for and my current project both with the image created facing upwards, now i'm intrigued and will change things over, but definately not until i get some sleep. also in one of my other threads Warpy mentioned possibly compiling together a games math tutorial of sorts, i haven't heard anything else about it since though but i hope he does because i think that it would be invaluble not only to me but many others. for now i just have to drill it in my head x-cos y-sin ;-) thanks again |
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| http://www.essentialmath.com/tutorial.htm There you go. |
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| cool thanks. |
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