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starting work on poly poly collisions

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This commit is contained in:
Fraser Graham 2013-11-24 14:25:19 -08:00
parent 5bb8a09165
commit 5b6dac04e0
3 changed files with 87 additions and 44 deletions
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72
collision.go Normal file
View File

@ -0,0 +1,72 @@
package govector
func Intersection(p1, p2 Point2d, v1, v2 Vector2d) (bool, Point2d) {
t := p2.Sub(p1).Cross(v2) / v1.Cross(v2)
s := p2.Sub(p1).Cross(v1) / v1.Cross(v2)
if t > 0 && t < 1 && s > 0 && s < 1 {
return true, p1.Add(v1.Scale(t))
}
return false, Point2d{0, 0}
}
func RectRectIntersection(r1 AABB2d, r2 AABB2d) bool {
return (r1.A.X < r2.B.X && r1.B.X > r2.A.X &&
r1.A.Y < r2.B.Y && r1.B.Y > r2.A.Y)
}
func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, Point2d) {
collision := false
inside := false
start_inside := PointInRect(p, r)
end_inside := PointInRect(p.Add(v), r)
if start_inside && end_inside {
inside = true
return collision, inside, p
} else {
wall_left, col1 := Intersection(p, r.A, v, Vector2d{X: 0, Y: r.B.Y - r.A.Y})
if wall_left {
return wall_left, inside, col1
}
wall_top, col2 := Intersection(p, r.A, v, Vector2d{X: r.B.X - r.A.X, Y: 0})
if wall_top {
return wall_top, inside, col2
}
wall_right, col3 := Intersection(p, r.B, v, Vector2d{X: 0, Y: -r.B.Y + r.A.Y})
if wall_right {
return wall_right, inside, col3
}
wall_bottom, col4 := Intersection(p, r.B, v, Vector2d{X: -r.B.X + r.A.X, Y: 0})
if wall_bottom {
return wall_bottom, inside, col4
}
return false, false, p
}
}
func ProjectPolygon(axis Vector2d, p Polygon2d) (min float32, max float32) {
min = axis.Dot(p.Points[0])
max = min
for _, point := range p.Points {
d := axis.Dot(point)
if d < min {
min = d
} else {
if d > max {
max = d
}
}
}
return min, max
}
func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, bool, Point2d) {
// TBD
return false, false, Point2d{}
}
func PolyPolyIntersection(p1 Polygon2d, v1 Vector2d, p2 Polygon2d, v2 Vector2d) bool {
return false
}

4
govector_test.go
View File

@ -182,7 +182,7 @@ func TestPtInRect(t *testing.T) {
pA := Point2d{5, 5}
pB := Point2d{15, 15}
r := Rect2d{
r := AABB2d{
A: pA,
B: pB,
}
@ -212,7 +212,7 @@ func TestRectIntersect(t *testing.T) {
pA := Point2d{5, 5}
pB := Point2d{15, 15}
r := Rect2d{
r := AABB2d{
A: pA,
B: pB,
}

55
vectorpoint.go
View File

@ -4,11 +4,17 @@ import (
"math"
)
type Rect2d struct {
type AABB2d struct {
A Point2d `json:A`
B Point2d `json:B`
}
type Polygon2d struct {
Points []Vector2d `json:"points"`
Normals []Vector2d `json:"normals"`
Origin Point2d `json:"origin"`
}
type Vector2d struct {
X float32 `json:"x"`
Y float32 `json:"y"`
@ -57,54 +63,19 @@ func (v1 Vector2d) Rotate(a float32) Vector2d {
return Vector2d{float32(x), float32(y)}
}
func Intersection(p1, p2 Point2d, v1, v2 Vector2d) (bool, Point2d) {
t := p2.Sub(p1).Cross(v2) / v1.Cross(v2)
s := p2.Sub(p1).Cross(v1) / v1.Cross(v2)
if t >= 0 && t <= 1 && s >= 0 && s <= 1 {
return true, p1.Add(v1.Scale(t))
}
return false, Point2d{0, 0}
}
func PointInRect(p Point2d, r Rect2d) bool {
func PointInRect(p Point2d, r AABB2d) bool {
return (p.X > r.A.X) && (p.X < r.B.X) && (p.Y > r.A.Y) && (p.Y < r.B.Y)
}
func RectFromPoint(p Point2d, size float32) Rect2d {
return Rect2d{
func RectFromPoint(p Point2d, size float32) AABB2d {
return AABB2d{
A: Point2d{X: p.X - size, Y: p.Y - size},
B: Point2d{X: p.X + size, Y: p.Y + size}}
}
func RectIntersection(r Rect2d, p Point2d, v Vector2d) (bool, bool, Point2d) {
collision := false
inside := false
start_inside := PointInRect(p, r)
end_inside := PointInRect(p.Add(v), r)
if start_inside && end_inside {
inside = true
return collision, inside, Point2d{X: 0, Y: 0}
} else {
wall_left, col1 := Intersection(p, r.A, v, Vector2d{X: 0, Y: r.B.Y - r.A.Y})
if wall_left {
return wall_left, inside, col1
}
wall_top, col2 := Intersection(p, r.A, v, Vector2d{X: r.B.X - r.A.X, Y: 0})
if wall_top {
return wall_top, inside, col2
}
wall_right, col3 := Intersection(p, r.B, v, Vector2d{X: 0, Y: -r.B.Y + r.A.Y})
if wall_right {
return wall_right, inside, col3
}
wall_bottom, col4 := Intersection(p, r.B, v, Vector2d{X: -r.B.X + r.A.X, Y: 0})
if wall_bottom {
return wall_bottom, inside, col4
}
return false, false, Point2d{X: 0, Y: 0}
}
func PolygonFromAABB(r AABB2d) Polygon2d {
// TBD
return Polygon2d{}
}
func (v Vector2d) Normalize() Vector2d {