I dont understand the relationship between a the normal planar map(an array) and its isometric rapresentation.Supposing i draw the map shifting right odd lines by TILE_X_SIZE/2,where i have to draw and object positioned at X,Y coordinates in the planar map? Actually i''m using and angled iso map obtained as a simple rotation of a planar map.My map is a big rombus so i had some problems to make it scroll...Someone could help?

hum hum... well there are multiple possibilities... the one I'm using works like follows:

Your map looks something like this:

     / y  /\/\  x   /\/\/  /\/\/\/ /\/\/\/\/ \/\/\/\/\/  \/\/\/\/   \/\/\/    \/\/     \/

Well, something like that, anyway ;-)

Notice the x and y. These are the "coordinates" in your map matrix. This means that the very topmost tile is [0,0] (or [1,1] for that matter)
The one on the very left is [0,4] (or [1,5])
The one at the very bottom is [4,4] (or [5,5])
And, as you'll have guessed, the one at the very right is [4,0] (or, as usual, [5,1])

This makes it easy to read a heightmap or, any kind of map, actually.

The only tricky bit abou this is the positioning. It had me thinking for a while, too.

Obviously, you have two counters, one for horizontal and one for vertical tile drawing. But how do you transform these to map coordintes?

My solution: (pseudocode)

For TileRow (0..TileRowMax)     For TileInRow (0..TilesPerRow)         MapX = X + Int(TileRow / 2 + 0.5) + TileInRow         MapY = Y + Int(TileRow / 2) - TileInRow     NextNext    

Where
TileRowMax is ScreenY*2/TileHeight + some tolerance. i.e. the number of rows of tiles.
TilesPerRow is ScreenX/TileWidth

X and Y are the map coordinates of the leftmost/topmost tile.

This is probably badly explained (it's pretty late and I've been feeling VERY strange the last days) but I hope it helped anyway... Ask if something (everything?) is unclear.

[edit]
ack...
I forgot the most important part - the actual screen coordinates:

X = [tilewidth] * TileInRow + ((TileRow & 1) - 1) * [tileheight]
Y = [tileheight] / (TileRow * 2) - Altitiude
[/edit]

- JQ, PWC Software
"programming is all about wasting time" -me


Edited by - JonnyQuest on October 25, 2000 5:46:18 PM

The forum doesn''t like the map...
I''ll try again here:

    /\y  /\/\  x  /\/\/\ /\/\/\/\/\/\/\/\/\\/\/\/\/\/ \/\/\/\/  \/\/\/   \/\/    \/

Strange why it didn''t work before

- JQ, PWC Software
"programming is all about wasting time" -me

I find the difficult part is going backwards from screen coordinates (a mouse click for example) to isometric grid coordinates.


Steve 'Sly' Williams
Tools Developer
Krome Studios

I know how to get map coordinates in my engine but my question was another :=))


I know the screen can be tiled drawing rows of tiles and shifting the odd ones by an half size of tile apart.I understand this give a sense of depth to the world you are showing. By i have some problems using this tiling metod. I start from a planar map where i put all objects of my world, it''s the world seen from above..:=) I dont understand how to calculate the position on the iso map of an object positioned at certain coordinates in my planar world view. In my map i simply use a bit of trigonometry and i get the iso coord.

quote: Original post by koatto

I know how to get map coordinates in my engine but my question was another :=))


I know the screen can be tiled drawing rows of tiles and shifting the odd ones by an half size of tile apart.I understand this give a sense of depth to the world you are showing. By i have some problems using this tiling metod. I start from a planar map where i put all objects of my world, it's the world seen from above..:=) I dont understand how to calculate the position on the iso map of an object positioned at certain coordinates in my planar world view. In my map i simply use a bit of trigonometry and i get the iso coord.

If i understand you right I think you need to perform a mod on the row you are trying to find. ie the world position of tile x, y would be

x_world_pos = (x * tile_width) - ((y % 2) * tile_width/2);
y_world_pos = (y * tile_height / 2);

you may need to change the + or minus of y % 2 section depending on which row is indented first... but y % 2 will tell you wether y is even or odd.

You also have to make sure you dont get your x's and y's confused in your array because in the array

int map_array[4][4] { 1,2,3,4 }
{1,2,3,4 }
{3,4,5,6,}
{1,1,1,1}

if you were to access element map_array[0][4] you may think you are acessing 1 but you actually getting a value of 4. so you must acess the array map_array[y][x] to have it represented cleanly


Lep



Edited by - Leprosy on October 25, 2000 11:44:07 PM