Aiming on Tanks Game

[theschaef]

Hey, I'm trying to make a "tanks" game and cannot get the aiming to work properly. Take a look at the code and see what you think i can do.. it doesnt shoot correctly forward and doesnt shoot at all when i make it go backwards.

code:

View.Set("graphics:max;max, offscreenonly") var x,y,xl1,yl1, xl2, yl2:int var projx, projy, shoot:int var angle:real var vel, velx, vely:real var chars:array char of boolean angle:=0.0 x:= 210 y:=200 xl1:=210 yl1:=110 xl2:=210 yl2:=135 vel:=3 velx:=0 vely:=3 projx:=210 projy:=110 shoot:=0 loop Draw.FillOval(210,100,18,10,1) Draw.FillBox(0,0,maxx,100,2) Draw.FillOval(x,y,5,5,4) Input.KeyDown(chars) if chars(KEY_RIGHT_ARROW)and y>100 or chars(KEY_RIGHT_ARROW) and x<200 and y=100 then x+=1 xl2+=1 elsif chars(KEY_LEFT_ARROW) and y>100 or chars(KEY_LEFT_ARROW) and x>200 and y=100 then x-=1 xl2-=1 elsif chars(KEY_ENTER)then shoot:=1 end if if shoot=1 then Draw.FillOval(projx, projy, 5, 5 ,2) projx+=round(velx) projy+=round(vely) end if y:= round(sqrt(-(x-195)**2+14400)) + 100 if xl2-xl1 not = 0 then angle:=arctand((yl2-yl1) / (xl2-xl1)) else angle:=90.0 end if velx:=vel * cosd(angle) vely:=vel * sind(angle) put round(velx) put round(vely) View.Update cls end loop

[Cervantes]

Welcome to CompSci.ca.

Format your code properly! It makes helping you a lot easier. It also makes it easier for you, the programmer. Commenting is good too.

[theschaef]

The main problem comes in when i have to use "round" for the x and y velocities of the projectile (ie. "projy += round (vely)"). I know that there is a way to do this because ive seen programs where it works, i just dont know how!

code:

View.Set ("graphics:max;max, offscreenonly") var x, y, xl1, yl1, xl2, yl2 : int var projx, projy, shoot : int var angle : real var vel, velx, vely : real var chars : array char of boolean angle := 0.0 x := 210 y := 200 xl1 := 210 yl1 := 110 xl2 := 210 yl2 := 135 vel := 3 velx := 0 vely := 3 projx := 210 projy := 110 shoot := 0 loop     %draws the tank, ground and aiming dot     Draw.FillOval (210, 100, 18, 10, 1)     Draw.FillBox (0, 0, maxx, 100, 2)     Draw.FillOval (x, y, 5, 5, 4)     % moves the aiming dot left or right     Input.KeyDown (chars)     if chars (KEY_RIGHT_ARROW) and y > 100 or chars (KEY_RIGHT_ARROW) and x < 200 and y = 100 then         x += 1         xl2 += 1     elsif chars (KEY_LEFT_ARROW) and y > 100 or chars (KEY_LEFT_ARROW) and x > 200 and y = 100 then         x -= 1         xl2 -= 1     elsif chars (KEY_ENTER) then         shoot := 1 % starts the projectile moving     end if     if shoot = 1 then         Draw.FillOval (projx, projy, 5, 5, 2)         projx += round (velx)         projy += round (vely)     end if     y := round (sqrt (- (x - 195) ** 2 + 14400)) + 100 %makes the aimer move in a circular motion     %finds the angle that the aimer is at relative to the ground     if xl2 - xl1 not= 0 then         angle := arctand ((yl2 - yl1) / (xl2 - xl1))     else         angle := 90.0     end if     %sets the x and y components of the velocity     velx := vel * cosd (angle)     vely := vel * sind (angle)     View.Update     cls end loop

[HellblazerX]

First of all, when the user presses the arrow keys, why have the x values changed when you can just change the angle?

So, to draw your aimer with the angle:

code:

Input.KeyDown (chars)     if chars (KEY_LEFT_ARROW) and angle < 180 then         angle += 1     elsif chars (KEY_RIGHT_ARROW) and angle > 0 then         angle -= 1     elsif chars (KEY_ENTER) then         shoot := 1 % starts the projectile moving     end if     x := round (50 * cosd (angle)) + 210     y := round (50 * sind (angle)) + 100     Draw.FillOval (210, 100, 18, 10, 1)     Draw.FillBox (0, 0, maxx, 100, 2)     Draw.FillOval (x, y, 5, 5, 4)

secondly, create a second "angle" variable, this time for the projectile, because after shooting, you can still control the projectile.