31 lines
926 B
Go
31 lines
926 B
Go
package engine
|
|
|
|
// Box describes an axis-aligned rectangular prism.
|
|
type Box struct {
|
|
X, Y, Z int // coordinate of the left-top-farthest corner
|
|
W, H, D int // width, height, depth
|
|
}
|
|
|
|
// IsoProjection translates an integer 3D coordinate into an integer 2D
|
|
// coordinate.
|
|
type IsoProjection struct {
|
|
ZX, ZY int
|
|
}
|
|
|
|
// Project projects a 3D coordinate into 2D.
|
|
// If ZX = 0, x is unchanged; similarly for ZY and y.
|
|
// Otherwise, x becomes x + z/ZX and y becomes y + z/ZY.
|
|
// Dividing Z is used because there's little reason for an isometric projection
|
|
// in a game to exaggerate the Z position, and integers are used to preserve
|
|
// "pixel perfect" calculation in case you are making the next Celeste.
|
|
func (π IsoProjection) Project(x, y, z int) (xp, yp int) {
|
|
// I'm using the π character because I'm a maths wanker
|
|
xp, yp = x, y
|
|
if π.ZX != 0 {
|
|
xp += z / π.ZX
|
|
}
|
|
if π.ZY != 0 {
|
|
yp += z / π.ZY
|
|
}
|
|
return xp, yp
|
|
}
|