58 lines
1.4 KiB
Go
58 lines
1.4 KiB
Go
|
package camera
|
||
|
|
|
||
|
|
import (
|
||
|
|
"zworld/plugins/math"
|
||
|
|
"zworld/plugins/math/mat4"
|
||
|
|
"zworld/plugins/math/vec3"
|
||
|
|
)
|
||
|
|
|
||
|
|
type Frustum struct {
|
||
|
|
Corners vec3.Array
|
||
|
|
Center vec3.T
|
||
|
|
Min vec3.T
|
||
|
|
Max vec3.T
|
||
|
|
}
|
||
|
|
|
||
|
|
var ndc_corners = vec3.Array{
|
||
|
|
vec3.New(-1, 1, -1), // NTL
|
||
|
|
vec3.New(1, 1, -1), // NTR
|
||
|
|
vec3.New(-1, -1, -1), // NBL
|
||
|
|
vec3.New(1, -1, -1), // NBR
|
||
|
|
vec3.New(-1, 1, 1), // FTL
|
||
|
|
vec3.New(1, 1, 1), // FTR
|
||
|
|
vec3.New(-1, -1, 1), // FBL
|
||
|
|
vec3.New(1, -1, 1), // FBR
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewFrustum creates a view frustum from an inverse view projection matrix by unprojecting the corners of the NDC cube.
|
||
|
|
func NewFrustum(vpi mat4.T) Frustum {
|
||
|
|
return Frustum{
|
||
|
|
Corners: ndc_corners,
|
||
|
|
Center: vec3.Zero,
|
||
|
|
Min: vec3.New(-1, -1, -1),
|
||
|
|
Max: vec3.One,
|
||
|
|
}.Transform(vpi)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Transform returns a new frustum with all its vertices transformed by the given matrix
|
||
|
|
func (f Frustum) Transform(transform mat4.T) Frustum {
|
||
|
|
corners := make(vec3.Array, 8)
|
||
|
|
center := vec3.Zero
|
||
|
|
min := vec3.New(math.InfPos, math.InfPos, math.InfPos)
|
||
|
|
max := vec3.New(math.InfNeg, math.InfNeg, math.InfNeg)
|
||
|
|
for i, corner := range f.Corners {
|
||
|
|
corner = transform.TransformPoint(corner)
|
||
|
|
center = center.Add(corner)
|
||
|
|
min = vec3.Min(min, corner)
|
||
|
|
max = vec3.Max(max, corner)
|
||
|
|
corners[i] = corner
|
||
|
|
}
|
||
|
|
center = center.Scaled(1 / 8.0)
|
||
|
|
return Frustum{
|
||
|
|
Corners: corners,
|
||
|
|
Center: center,
|
||
|
|
Min: min,
|
||
|
|
Max: max,
|
||
|
|
}
|
||
|
|
}
|