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converted intersection to return point pointers

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This commit is contained in:
Stephen McQuay 2014-01-15 23:11:40 -08:00
parent 282bcb448f
commit 8a5e55e410
2 changed files with 25 additions and 19 deletions
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21
collision.go
View File

@ -4,14 +4,15 @@ import (
"math" "math"
) )
func Intersection(p1, p2 Point2d, v1, v2 Vector2d) (bool, Point2d) { func Intersection(p1, p2 Point2d, v1, v2 Vector2d) (bool, *Point2d) {
t := p2.Sub(p1).Cross(v2) / v1.Cross(v2) t := p2.Sub(p1).Cross(v2) / v1.Cross(v2)
s := p2.Sub(p1).Cross(v1) / v1.Cross(v2) s := p2.Sub(p1).Cross(v1) / v1.Cross(v2)
if t > 0 && t < 1 && s > 0 && s < 1 { if t > 0 && t < 1 && s > 0 && s < 1 {
return true, p1.Add(v1.Scale(t)) intersection := p1.Add(v1.Scale(t))
return true, &intersection
} }
return false, Point2d{0, 0} return false, nil
} }
func RectRectIntersection(r1 AABB2d, r2 AABB2d) bool { func RectRectIntersection(r1 AABB2d, r2 AABB2d) bool {
@ -20,14 +21,14 @@ func RectRectIntersection(r1 AABB2d, r2 AABB2d) bool {
} }
// returns collision, inside, point of collision // returns collision, inside, point of collision
func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, Point2d) { func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, *Point2d) {
collision := false collision := false
inside := false inside := false
start_inside := PointInRect(p, r) start_inside := PointInRect(p, r)
end_inside := PointInRect(p.Add(v), r) end_inside := PointInRect(p.Add(v), r)
if start_inside && end_inside { if start_inside && end_inside {
inside = true inside = true
return collision, inside, p return collision, inside, nil
} else { } else {
wall_left, col1 := Intersection(p, r.A, v, Vector2d{X: 0, Y: r.B.Y - r.A.Y}) wall_left, col1 := Intersection(p, r.A, v, Vector2d{X: 0, Y: r.B.Y - r.A.Y})
if wall_left { if wall_left {
@ -46,7 +47,7 @@ func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, Point2d) {
return wall_bottom, inside, col4 return wall_bottom, inside, col4
} }
return false, false, p return false, false, nil
} }
} }
@ -66,11 +67,11 @@ func ProjectPolygon(axis Vector2d, p Polygon2d) (min float32, max float32) {
return min, max return min, max
} }
func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, Point2d) { func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, *Point2d) {
// TODO - need to test point in polygon for start and end to detect wholly // TODO - need to test point in polygon for start and end to detect wholly
// inside situations // inside situations
intersection := false intersection := false
i_point := Point2d{} var iPoint *Point2d
distance_sq := float32(math.MaxFloat32) distance_sq := float32(math.MaxFloat32)
for point, _ := range r.Points { for point, _ := range r.Points {
@ -80,13 +81,13 @@ func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, Point2d) {
intersection = true intersection = true
d_sq := pt.Sub(p).MagSquared() d_sq := pt.Sub(p).MagSquared()
if d_sq < distance_sq { if d_sq < distance_sq {
i_point = pt iPoint = pt
distance_sq = d_sq distance_sq = d_sq
} }
} }
} }
return intersection, i_point return intersection, iPoint
} }
func PointInPolygon(p Point2d, py Polygon2d) bool { func PointInPolygon(p Point2d, py Polygon2d) bool {

21
govector_test.go
View File

@ -220,7 +220,7 @@ func TestRectIntersect(t *testing.T) {
type result struct { type result struct {
collided bool collided bool
inside bool inside bool
pos Point2d pos *Point2d
} }
tests := []struct { tests := []struct {
rect AABB2d rect AABB2d
@ -239,7 +239,7 @@ func TestRectIntersect(t *testing.T) {
expected: result{ expected: result{
collided: false, collided: false,
inside: true, inside: true,
pos: Point2d{1, 1}, pos: nil,
}, },
}, },
// bottom // bottom
@ -253,7 +253,7 @@ func TestRectIntersect(t *testing.T) {
expected: result{ expected: result{
collided: true, collided: true,
inside: false, inside: false,
pos: Point2d{10, 5}, pos: &Point2d{10, 5},
}, },
}, },
// wall left // wall left
@ -267,7 +267,7 @@ func TestRectIntersect(t *testing.T) {
expected: result{ expected: result{
collided: true, collided: true,
inside: false, inside: false,
pos: Point2d{0, 5}, pos: &Point2d{0, 5},
}, },
}, },
// wall right // wall right
@ -281,7 +281,7 @@ func TestRectIntersect(t *testing.T) {
expected: result{ expected: result{
collided: true, collided: true,
inside: false, inside: false,
pos: Point2d{10, 5}, pos: &Point2d{10, 5},
}, },
}, },
// wall top // wall top
@ -295,7 +295,7 @@ func TestRectIntersect(t *testing.T) {
expected: result{ expected: result{
collided: true, collided: true,
inside: false, inside: false,
pos: Point2d{5, 10}, pos: &Point2d{5, 10},
}, },
}, },
// outside // outside
@ -309,7 +309,7 @@ func TestRectIntersect(t *testing.T) {
expected: result{ expected: result{
collided: false, collided: false,
inside: false, inside: false,
pos: Point2d{5, -1}, pos: nil,
}, },
}, },
} }
@ -322,10 +322,15 @@ func TestRectIntersect(t *testing.T) {
t.Errorf("RectIntersection Error") t.Errorf("RectIntersection Error")
t.Errorf("unexpected inside: expected: %t, actual: %t", test.expected.inside, inside) t.Errorf("unexpected inside: expected: %t, actual: %t", test.expected.inside, inside)
} }
if pos != test.expected.pos { if test.expected.pos == nil && pos != nil {
t.Error("expected nil position, got non-nil")
}
if pos != nil && test.expected.pos != nil {
if *pos != *test.expected.pos {
t.Errorf("unexpected collision point: expected: %+v, actual: %+v", test.expected.pos, pos) t.Errorf("unexpected collision point: expected: %+v, actual: %+v", test.expected.pos, pos)
} }
} }
}
} }