image collision/deletion problem
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| please see above file the problem i have is that the bullet goes upwards yet when it hits the alien the 'imagecollision' command somehow doesnt recognise the hit until the bullet is past the alien. any ideas why this is please? thanks graham |
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Hmmm, i've had a look see. This bit seems to be a bit odd. You using variables to offset the positioning of the bullets and aliens. now:For enemy.enemy=Each enemy If enemy\alive <>0 Then DrawImage (enemy\image,enemy\x+boardxstart,enemy\y+boardystart,enemy\imagehandle) Next ;draw bullets For bullet.bullet=Each bullet If bullet\alive <>0 Then DrawImage (bullet\image,bullet\x+boardxstart,bullet\y+tilewidth,bullet\imagehandle) Rect bullet\x+boardxstart,bullet\y+tilewidth,1,1 Next you use "tilewidth" to position the Y of the bullets, BUT, you use boardYstart to position the aliens. Now, your basically drawing them in one position and checking the collisions is different positions. Basically, it's the draw bullets line that mucking it up. It should be: ;draw bullets For bullet.bullet=Each bullet If bullet\alive <>0 Then DrawImage (bullet\image,bullet\x+boardxstart,bullet\y+boardystart,bullet\imagehandle) Next Note, the change is using the variable "boardystart" to position the bullet on the Y axis. :o) |
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Oh, also, i notice you aren't actually deleting the bullets once they've hit something. Add in:If bullet\alive = 0 Then Delete bullet.bullet End If In the "PlayerCollisions()" function, just below where you check the Y position of the bullet. :o) To make the function read: Function PlayerCollisions() ;Reset the collisions variables playerup = False playerleft = False playerright=False playerdown = False ;Start Collision Detection ;solid For x = 0 To mapsizex For y = 0 To mapsizey If map(0,x,y)>0 Then;if there is something occupying the current x,y position in the Map array If ImagesCollide(player\image ,player\x+collisioncheck ,player\y ,player\imagehandle ,gfx_tiles,x*32,y*32,map(0,x,y)) Then playerright = True ;IF the player collided with the current tile on his right If ImagesCollide(player\image ,player\x-collisioncheck ,player\y ,player\imagehandle ,gfx_tiles,x*32,y*32,map(0,x,y)) Then playerleft = True ;IF the player collided with the current tile on his left If ImagesCollide(player\image ,player\x ,player\y+collisioncheck ,player\imagehandle ,gfx_tiles,x*32,y*32,map(0,x,y)) Then playerdown = True;IF the player collided with the current tile below him If ImagesCollide(player\image ,player\x ,player\y-collisioncheck ,player\imagehandle ,gfx_tiles,x*32,y*32,map(0,x,y)) Then playerup = True;IF the player collided with the current tile Above Him EndIf Next Next ;check collision for the pickups For pickup.pickup=Each pickup If pickup\alive =1 Then If ImagesCollide(player\image,player\x,player\y,player\imagehandle ,pickup\image ,pickup\x,pickup\y ,pickup\imagehandle ) Then pickup\alive =0 ;remove the pickup pickupid=pickupid-1 player\score=player\score+10 EndIf End If Next Local bullet_dead = 0 ;check collision for the bullets For bullet.bullet=Each bullet If bullet\alive =1 Then bullet\y =bullet\y -5 ;move the bullet upwards if not hit anything For enemy.enemy=Each enemy If enemy\alive =1 Then If ImagesCollide(enemy\image,enemy\x,enemy\y,enemy\imagehandle ,bullet\image ,bullet\x,bullet\y ,bullet\imagehandle ) Then enemy\alive =0 ;remove the enemy bullet\alive =0 ; remove the bullet player\score=player\score+10 End If EndIf Next If bullet\y=<0 Then ;if bullet off top of screen then delete and dont show bullet\alive =0 End If If bullet\alive = 0 Then Delete bullet.bullet End If End If Next End Function I also moved the part where you move the bullets, to before the collision check is done, to make sure it doesn't miss. |
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| that works great, thanks for your time and help graham |
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