Game Engine problem (based off of the tutorial)

[rcbhs]

Soooo, I am trying to expand the Game Engne tutorial to work with my own game. Now a quick explination is...I want to make it so I can place objects as sprites instead of pictures. I am not exactly sure how to do this. Where would I put the Sprite.New, Sprite.SetHeight, Sprite.SetLocation, etc... I am really confused here.

MageObjects.t:

code:

class Player     inherit Mage     stepAmount := 4     body procedure DrawObject ()         Pic.Draw (PicId, posX, posY, picMerge)     end DrawObject     body procedure Update (Keys : array char of boolean)         if (Keys (KEY_DOWN_ARROW)) then             Move (0, -stepAmount, true)         end if         if (Keys (KEY_UP_ARROW)) then             Move (0, stepAmount, true)         end if         if (Keys (KEY_LEFT_ARROW)) then             Move (-stepAmount, 0, true)         end if         if (Keys (KEY_RIGHT_ARROW)) then             Move (stepAmount, 0, true)         end if     end Update end Player

mageGame.t (driver):

code:

setscreen ("graphics:640;480,offscreenonly") include "mageEngine.t" include "mageObjects.t" var Engine : pointer to GameEngine new Engine Engine -> Create (3) var Player_ : pointer to Player new Player_ Engine -> AddObject (Player_) -> Create (".\\Mage\\BlackMageDownArrow.gif" ,320 ,60) Engine -> Run ()

mageEngine.t:

code:

class Mage     export Create, DrawObject, Update,         posX, posY, stepAmount, Direction     var PicId : int     var ImageName : string     var posX : int := 400     var posY : int := 300     var stepAmount : int     var Direction : int := 0     var mageSpriteUp, mageSpriteDown, mageSpriteLeft : int     var magePicUp, magePicDown, magePicLeft, magePicRight : int     procedure Create (img : string, posx, posy : int)         ImageName := img         posX := posx         posY := posy         PicId := Pic.FileNew (ImageName)     end Create     procedure Move (x, y : int, relative : boolean)         if (relative) then             posX += x             posY += y         else             posX := x             posY := y         end if     end Move     procedure MoveDir ()         Move (round (stepAmount * cosd (Direction)), round (stepAmount * sind (Direction)), true)     end MoveDir     deferred procedure DrawObject ()     deferred procedure Update (Keys : array char of boolean) end Mage %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% class GameEngine     import Mage, Input     export Create, Run, AddObject     var Entities : flexible array 0 .. 1 of pointer to Mage     var Keys : array char of boolean     var Fps : int     var FpsMilli : int     var lastTime : int     var thisTime : int     procedure Create (fps : int)         Fps := fps         FpsMilli := 100 div Fps         lastTime := Time.Elapsed     end Create     procedure Run ()         loop             thisTime := Time.Elapsed             if (thisTime - lastTime >= FpsMilli) then                 lastTime := thisTime                 cls                 Input.KeyDown (Keys)                 if (Keys (KEY_ESC)) then                     return                 end if                 if (upper (Entities) - 1 > 0) then                     for i : 0 .. upper (Entities) - 2                         Entities (i) -> Update (Keys)                         Entities (i) -> DrawObject ()                     end for                 end if                 View.Update ()             end if         end loop     end Run     function AddObject (obj : pointer to Mage) : pointer to Mage         Entities (upper (Entities) - 1) := obj         new Entities, upper (Entities) + 1         result obj     end AddObject end GameEngine

Well you don't have the files so it won't work, however that is the code there. So my problem is, instead of a picture I want that to be a sprite (so I can do some movement animation. Also, what if I don't want 8 point movement? Just 4 point? What do I change there?)

[DemonWasp]

Well, there are a few strategies:

Simple, Easy Strategy:
Each player has their own image / sprite. In the class, add a method called "setup" (these are technically called "constructors", but I don't think Turing has those); that's where you would do your Pic.New and your Sprite.New calls. You should also add a "destroy" method (destructor) which calls Sprite.Free and Pic.Free.

Then, in move, you'd do the Sprite.SetLocation.

Harder, More Efficient Strategy:
A lot of your players may be using the same image (particularly if you want to use things like projectiles). It would be really cumbersome to load the same image over and over, so why not make a "library" of images. A library looks like this:

code:

class ImageLibrary     function GetImage ( filename : string ) : int         % If we haven't loaded filename yet, load the picture, and store it in a list of filename-picture ID pairs.         % If we HAVE loaded it already, just return the ID, instead of loading the picture again.     end GetImage end ImageLibrary

In this case, Pic.New is within ImageLibrary.GetImage, while Sprite.New is still in a constructor ("setup") method and Sprite.Free is in a destructor ("destroy") method. Pic.Free should only be called in ImageLibrary.Destroy, which is only called to clean up after your game.

This strategy is somewhat more difficult, but should save you headaches later with running out of the number of images you can load and performance issues.

4 versus 8-point movement
The solution to this is somewhere between the Update() and Move() procedures, you need to limit the entities to 4-point movement.