Orbital Game Help

[Luminosity]

What is it you are trying to achieve?
Trying to make a game like Orbital on the Ipod Touch.


What is the problem you are having?
So far the project is going well, the program runs fine for about 3-5 mins but then will crash and give me an Illegal Picture ID error. I am not using any picture files for the project yet, but I only used the Pic.New function to be able to rotate an object. I think the problem may be caused by the Pic.Free function, but I do not know how to fix this.


Describe what you have tried to solve this problem
The only way I got it to work again is by closing the entire Turing program, but it will still crash again after the 3-5 mins.


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)
My game code so far, the shooting is not implemented yet.

Turing:

setscreen ("graphics:400;600, nobuttonbar, offscreenonly") const cx := maxx div 2 const cy := maxy div 2 var angle, slope : real := 0 var chars : array char of boolean var mouseX, mouseY, mouseButton, shotX, shotY : int := 0 % Changeable variables var shotSize := 10 var cannonLength := 80 var cannonWidth := 10 % Checks the mouse's boundaries procedure mouseBounds     % If the mouse's  x position is outside of the window then the mouseX value is still inside     if mouseX < 0 then         mouseX := 0     elsif mouseX > maxx then         mouseX := maxx     end if     % If the mouse's  y position is outside of the window then the mouseY value is still inside     if mouseY < 0 then         mouseY := 0     elsif mouseY > maxy then         mouseY := maxy     end if end mouseBounds % Limits the angle (and slope value) of the cannon procedure limitAngleSlope (minAngle, maxAngle : int)     % If the angle is greater than the max angle it becomes the max angle and the slope value is equal to the maxangle     if angle > maxAngle then         angle := maxAngle         slope := tand (angle)         % If the angle is less than the min angle it becomes the max angle and the slope value is equal to the minangle     elsif angle < minAngle and mouseX >= 200 then         angle := minAngle         slope := tand (angle)     elsif angle < minAngle and mouseX < 200 then         angle := maxAngle         slope := tand (angle)     end if end limitAngleSlope % Creates a picture of a cannon var picCannon, rotateCannon : int drawfillbox (0, 0, maxx, maxy, black) drawfillbox (cannonLength - cannonWidth, 0, cannonLength + cannonWidth, cannonLength, grey) picCannon := Pic.New (0, 0, cannonLength * 2, cannonLength) % Clears the screen cls % Main Loop loop     Input.KeyDown (chars)     View.Update     % Draws background     drawfillbox (0, 0, maxx, maxy, black)     % Finds the coordinates of the mouse     Mouse.Where (mouseX, mouseY, mouseButton)     % Checks the mouse boundaries     mouseBounds     % If the mouse's x position is not equal to the center of the screen     if mouseX not= cx then         % Then calculate the slope and the angle         slope := mouseY / (mouseX - cx)         angle := arctand (slope)     else         % Else the angle is 90 (and slope is undefined)         angle := 90     end if     % Changes the negative angles to the correct angle     if angle < 0 then         angle := angle + 180     end if     % Limits the angle (and slope value) of the cannon if it is less than 10 degrees or greater than 170 degrees     limitAngleSlope (10, 170)     % Rotates the barrel of the cannon according to the angle     rotateCannon := Pic.Rotate (picCannon, round (angle) - 90, cannonLength, 0)     % Draws the barrel of the cannon according to the rotation     Pic.Draw (rotateCannon, cx - cannonLength, 0, picMerge)     Pic.Free (rotateCannon)     % Draws the cannon circle     drawfilloval (cx, 0, cannonLength div 2, cannonLength div 2, grey)     drawoval (cx, 0, cannonLength div 2 - 5, cannonLength div 2 - 5, white)     drawoval (cx, 0, cannonLength div 2, cannonLength div 2, white)     % Draws the red line     drawline (0, 30, maxx, 30, red)     % Calculates the coordinates of the shot     shotX := round (cannonLength * cosd (angle))     shotY := round (cannonLength * sind (angle))     % If the left button is pressed then draw the shot     if mouseButton = 1 then         % Draws the shot         drawoval (shotX + cx, shotY, shotSize, shotSize, white)         drawoval (shotX + cx, shotY, shotSize - 5, shotSize - 5, white)     end if     % Quits when the user presses q     if chars ('q') then         Pic.Free (picCannon)         delay (200)         exit     end if end loop

Please specify what version of Turing you are using
4.1.1

[DemonWasp]

You allocate a new picture every time you loop (with Pic.Rotate, which makes a new picture). You only deallocate that picture with Pic.Free if the player is pressing Q.

You should rotate the image before you start play, and store the rotated versions of the image in an array of ints. Alternately, you can make sure that a Pic.New / Pic.FileNew / Pic.Rotate is ALWAYS matched with a Pic.Free.

[Raknarg]

Or you could simplify this and learn Trig

[Luminosity]

@DemonWasp thanks for the suggestions, but I tried both and it didn't work out. The arrays didn't help, it still has the same problem. By matching up the Pic.Free, the program still doesn't work and it gives me an error saying Pic was freed.

@Raknarg could you tell me how to simplify this? thanks

[Tony]

Arrays help greatly, but that assumes that you'll be using less than 1000 pictures.

Quote:

By matching up the Pic.Free, the program still doesn't work and it gives me an error saying Pic was freed.

This means that new and free were not matched up correctly (as you are letting go of a picture, and then trying to use it after).

[Raknarg]

If you really wanted to use trig, you would use this:

Turing:

View.Set ("offscreenonly") var x, y, dx, dy : array - 5 .. 5 of int var mx, my, b, t : int for i : -5 .. 5     x (i) := 200     y (i) := 200     dx (i) := 200     dy (i) := 200 end for loop     Mouse.Where (mx, my, b)     for i : -5 .. 5         Draw.Line (dx (i), dy (i), x (i), y (i), 7)     end for     if b = 1 then         if mx > 200 then             t := round (arctand ((my - 200) / (mx - 200)))         elsif mx < 200 then             t := round (arctand ((my - 200) / (mx - 200))) - 180         end if         for i : -5 .. 5             dx (i) := 200 + round (i * cosd (t - 90))             dy (i) := 200 + round (i * sind (t - 90))             x (i) := dx (i) + round (100 * cosd (t))             y (i) := dy (i) + round (100 * sind (t))         end for     end if     View.UpdateArea (0, 0, maxx, maxy)     delay (20)     cls end loop

However, this is kindof bulky and not quite as effective. If you want a better effect, just use Draw.ThickLine