How do load an image into a 2D array element? - arrays

Question

I'm currently doing my A-Level Computing project for which I am making my own version of the classic game Space Invaders.
To create the wave of space invaders I want to use a 2D array of images, where the images are loaded from a disk and then displayed on the form but I am unsure of how load the images into the array and then display the array on a form.
The current arrays are:
ImagePaths:array [1..3] of string =('SpaceInvader1.jpg', 'SpaceInvader2.jpg', 'SpaceInvader3.jpg');
Wave:array[1..11, 1..5] of TImage; x,y:integer;
What I would like to know is: how would I load an image into an array element? eg how would I load 'SpaceInvader1.jpg' to array element [1,1]?
Any help would be greatly appreciated.

Answer 1

If you're going to be coding graphical animations, you probably won't want to do it directly on the form. Trying to move things around can be tricky, especially if you want to animate smoothly and not get a lot of flicker and graphical artifacts.
It would be better to use a rendering library. The workflow goes like this:
Create a rendering context on the form. This is a control that provides a surface for graphical animations to run on.
Load your three images into memory.
Create an array of objects to represent the game data associated with your monsters. (Position, movement direction and speed, etc.) It can be flat or 2D, whichever works better for you.
Set up a render loop that goes like this:
For each monster in the array, draw it at its position.
Draw the player's ship and all projectiles.
Check for collisions and handle appropriately.
Check for player input and handle appropriately.
You can find plenty of information on rendering libraries for Delphi in the forums at Pascal Game Development.

Answer 2

You have the following declarations:
ImagePaths:array [1..3] of string =(
'SpaceInvader1.jpg',
'SpaceInvader2.jpg',
'SpaceInvader3.jpg'
);
Wave: array[1..11, 1..5] of TImage;
You want to know how to populate the array of images. It is quite wasteful to create 55 images when 3 will suffice. So instead of that, use indirection. Store references to the images. And TImage is a visual component, and so not appropriate for a sprite.
I would hold the images in an array like this:
Sprites: array [1..3] of TBitmap;
And populate it
JPEGImage := TJPEGImage.Create;
try
for i := 1 to 3 do
begin
JPEGImage.LoadFromFile(ImagePaths[i]);
Sprites[i] := TBitmap.Create;
Sprites[i].Assign(JPEGImage);
end;
finally
JPEGImage.Free;
end;
Then populate your Wave array like this, for example:
Wave: array[1..11, 1..5] of TBitmap;
....
for i := 1 to 11 do
for j := 1 to 5 do
Wave[i,j] := Sprites[1];// or whichever sprite you want
Of course your sprites may be better with a real name rather than in an array.
Some other comments:
JPEG is a bad format for a game sprite. It is a lossy format. A plain Windows bitmap would be fine, as would a GIF or PNG.
I'd much rather see the images as embedded resources. Then your executable can stand alone.
I'd also far rather see your Waves array holding the state of each invader. And then you would create a function that would render that state onto a canvas.