func (v *Viewport) TileCoordinatesToScreen(tx, ty float64, config DisplayConfig) (float64, float64) {
var trans allegro.Transform
trans.Build(float32(-v.x), float32(-v.y), float32(v.xZoom), float32(v.yZoom),
ISOMETRIC_ROTATION)
x, y := trans.Apply(float32(tx), float32(ty))
return float64(x), float64(y)
}
func (v *Viewport) ScreenCoordinatesToTile(sx, sy int, config DisplayConfig) (float64, float64) {
// I have never been more ashamed of code I have written
w, h := float64(config.TileW), float64(config.TileH)
fx, fy := float32(sx), float32(sy)
var trans allegro.Transform
trans.Identity()
// Builds the viewport alignment matrix
trans.Build(float32(-v.x), float32(-v.y), float32(v.xZoom), float32(v.yZoom),
0)
// Invert it to get back to pixel coordinates
trans.Invert()
// We need to translate back half a width to get to the pivot of the tiles
trans.Translate(-float32(w/2), 0)
x, y := trans.Apply(fx, fy)
// Then we manually rotate it (because I'm bad at maths I guess)
tx := float64(float64(y)*w-float64(x)*h) / (w * h)
ty := float64(float64(y)*w+float64(x)*h) / (w * h)
return tx, ty
}