OpenGl and selective drawing

[code_glitch]

All fixed now. Engine seems to run at 600tiles/sec if you update to screen each time. If you dont its somewhere over 55,000 tiles/second on my 1.2ghz su4100 at 45% background cpu usage. Not bad if I may say so myself. Here is a demo program of it all:

program TileSetTest;

uses
    Prometheus_Vid;

var
    TS: TileSet;
    cx: Int64;
    cy: Int64;
    c: Int64;

begin
    PrometheusVid_Start();
    CreateWindow(1280, 600, 32);
    UpdateWindow();
    
    
    TS.LoadFromImageFile('TileData.png');
    TS.SetOffset(2,3);
    TS.SetSpacing(1,1);
    TS.SetTileSize(16,16);
    TS.SetTileTable(140,140);
    Ts.SetTiles(10000);
    Ts.Update();
    
    cx := 0;
    cy := 1;
    c := 0;
    repeat
        cx := cx + 1;
        c := c + 1;
        Ts.DrawTile((cx - 1) * 16, (cy - 1) * 16, c);
        if cx >= Ts.TilesPerRow then
            begin
                cx := 0;
                cy := cy + 1;
            end;
    until cy > 500;
    UpdateCanvas();
    readln();
end.

The SetTiles() is not actually required but I put it in as a fallback if something like TS.Update fails entirely.

PS: This uses <~20mb of ram to load a alpha 2739x2264 png tilesheet and draw it along with all other prometheus crap.