a word about the minimap;


The maps is rendered on a 640 x 480 texture

the tm as we know it, scematized;

A1, A2, A3
B1, B2, B3
C1, C2, C3
D1, D2, D3

the matrix describes the scale, rotation and position of the objects within the this texture space.

For a simple topview render, all we need is the scale and position of the objects.

The scale is calculated by finding the maximal size of the map in height and width. Because we want to have the
amount of map in view, we either take the maximal width in X or the maximal width in Y. ( in x, being in horizontal
direction relative to the texture, in y vertical direction.)

We divide the maximal X width of the map by 640, and the maximal Y width of the map by 480.
Either one of these resulting values is smaller than the other and will determine the scale we will use. For example,
let's say that the height and widht of the map is equal, say 200 units. The width ration will then be 640 / 200 = 3.2 and the
height ration 200 / 480 = 1.4 . clearly, the height ration is smaller than the width, so we will use this scale for our minimap.
(If we would use the width ration, we would lose a part of our minimap at the top and bottom of our texture)

we now have a units to pixel ration of 1.4 or in other words, one world unit is 1.4 pixels large!

The position of the maps is calculated by taking the center of the entire race map, and compare it to the origin of the world.
For instance, our track's center lies at x=50 y=3

this means that the minimap should shift 50 pixels to the right, and 3 pixels to the top in order to get it centered in the texture

the lowest row of the matrix takes care of that. It maps the units on top of the center of the texture. horizontally, you
should substract that 50 from the 320 (half the texture width), and vertically add 3 to 240. 

putting all this in the tm we would get

1.4, 0, 0
0, 0, 0
0, 1.4, 0
270, 243, 0

that's it. When all is right, the minimap will show up correctly ingame.

I suppose it is possible to do more funky stuff, like setting up an orthagonal view for the minimap. It would require you
to incorporate rotations in the transformation matrix, which I haven't quite mastered yet. Working on it though.