func (this *HeightMap) Get2f(x, y float32) float32 {
l := math32.Floor(x)
r := math32.Floor(x + 1)
b := math32.Floor(y)
t := math32.Floor(y + 1)
bl := this.Get(int(l), int(b))
br := this.Get(int(r), int(b))
tl := this.Get(int(l), int(t))
tr := this.Get(int(r), int(t))
bh := bl*(r-x) + br*(x-l)
th := tl*(r-x) + tr*(x-l)
h := bh*(t-y) + th*(y-b)
return h
}
func (m *HeightMap) Normal2f(x float32, y float32) (n mgl.Vec3) {
x0 := int(math32.Floor(x))
x1 := x0 + 1
y0 := int(math32.Floor(y))
y1 := y0 + 1
n00 := m.Normal(x0, y0)
n10 := m.Normal(x1, y0)
n01 := m.Normal(x0, y1)
n11 := m.Normal(x1, y1)
w := x - float32(x0)
h := y - float32(y0)
n0 := n00.Mul(1 - w).Add(n10.Mul(w))
n1 := n01.Mul(1 - w).Add(n11.Mul(w))
n = n0.Mul(1 - h).Add(n1.Mul(h))
return
}
func raytrace(x0, y0, x1, y1 float32, visit func(x, y int) bool) {
dx := math32.Abs(x1 - x0)
dy := math32.Abs(y1 - y0)
x := int(math32.Floor(x0))
y := int(math32.Floor(y0))
var x_inc, y_inc int
var err float32
if dx == 0 {
x_inc = 0
err = math32.Inf(1)
} else if x1 > x0 {
x_inc = 1
err = (math32.Floor(x0) + 1 - x0) * dy
} else {
x_inc = -1
err = (x0 - math32.Floor(x0)) * dy
}
if dy == 0 {
y_inc = 0
err -= math32.Inf(1)
} else if y1 > y0 {
y_inc = 1
err -= (math32.Floor(y0) + 1 - y0) * dx
} else {
y_inc = -1
err -= (y0 - math32.Floor(y0)) * dx
}
for visit(x, y) {
if err > 0 {
y += y_inc
err -= dx
} else {
x += x_inc
err += dy
}
}
}
func (this *EntityGrid) Remove(e *Entity) {
x := int(math32.Floor(e.Position[0])) & (this.W - 1)
y := int(math32.Floor(e.Position[1])) & (this.H - 1)
index := this.W*y + x
this.data[index] = remove(this.data[index], e)
}