Comments on: working with isometric maps

By: Ray Johannessen

Ray Johannessen — Sat, 04 Jul 2009 13:31:04 +0000

I’ve been working on an isometric engine for the last couple months. I found what seems to be the best method for screen-to-map conversions. I know it works with diamond-type isometric maps, not sure about other types (like staggered and slide).

It’s a simple algebraic equation, rather than having to mess with sqrts and angles, as I know they’re not the most efficient calculations cpu-wise.

Point tileID;
tileID.X = ((tileWidth * mouse.Y) + (tileHeight * mouse.X)) /
(tileWidth* tileHeight);
tileID.Y = ((tileWidth * mouse.Y) – (tileHeight * mouse.X)) /
(tileWidth* tileHeight);

By: Jörn

Jörn — Fri, 03 Apr 2009 12:54:21 +0000

Great help for a tricky problem! Thanks! And also thanks for the comments that helped aswell!!

By: athanazio

athanazio — Thu, 08 Jan 2009 23:59:54 +0000

great job yepke !

By: yepke

yepke — Thu, 08 Jan 2009 23:20:12 +0000

I think you are doing a lot of extra calculations! You can usde much more maths.
It took me all day, but I get the same results now:
public void getTileAt(int screenX, int screenY){

//adjustment will be 4*tileWidth in your example.
double x = screenX – tileWidth;

//Y*2 -> squares instead of diamonds => 90° = PI/2
//easyer calculations!
double y = screenY*2;

//distance from origin to point in ISO
double r = Math.sqrt((x*x) + (y*y));
double theta = Math.atan2(x, y);
double angle = (Math.PI/4) – theta;

//length of the side of one tile (128/64 are mine)
double rr = Math.sqrt(2*64*64);

//’real x’ is the projection of screen distance by the angles cos
double rx = Math.floor(r* Math.cos(angle) / rr);

//’real x’ is the projection of screen distance by the angles sin
double ry = Math.floor(r* Math.sin(angle) / rr);

System.out.printf(“(%.0f,%.0f)\n”,rx,ry);
}

By: Athanazio » thinking about sioti

Athanazio » thinking about sioti — Wed, 03 Sep 2008 02:27:11 +0000

[...] my isometric efforts, I will follow my friend advice, and make plain 2D, lets see If I can make it [...]

By: athanazio

athanazio — Sat, 21 Jun 2008 13:49:26 +0000

hehehe Its true Lis, is almost isometric, but what made me happy on that is the fact that I figure it out how to map the screen to the points =)
but thx for pointing me that

By: Lis

Lis — Sat, 21 Jun 2008 12:12:49 +0000

What you created isn’t an isometric view – with computers the angle is different from the actual isometric angle. You have to go two pixels across, one pixel up every time to create an isometric line.