Sorry, no screenshots, and not likely to ever have any. The library I'm working on will have functions for various collisions. Currently, I only have simple cases programmed so far:
CURRENT FUNCTIONS
2D
Line segment - Ellipse
Line segment - Circle
Distance from point to a line segment
Length of a line
point in a triangle
box - box (AABB)
circle - circle
Point - Capsule
3D
Distance from a point to a plane
I plan to include a full set of 2D and 3D collision functions including OBB, ray-plane, cylinder-sphere, capsule-capsule, triangle-box, and many more.
I must be up early tomorrow and so I didn't want to start anything complicated tonight, hence the simple functions.
type Vector2D
x as float
y as float
endtype
type Vector3D
x as float
y as float
z as float
endtype
type Line2D
a as Vector2D
b as Vector2D
endtype
type Line3D
a as Vector3D
b as Vector3D
endtype
type Capsule2D
ln as Line2D
radius as float
endtype
type Circle2D
center as Vector2D
radius as float
endtype
type Ellipse2D
center as Vector2D
radius as Vector2D
endtype
rem point on the plane
rem plane's normal
type Plane
p as Vector3D
n as Vector3D
endtype
`==============================================
`
`==============================================
function CX_2D_ReflectVector(v as Vector2D, n as Vector2D)
endfunction
`==============================================
`
`==============================================
function CX_3D_ReflectVector(v as Vector3D, n as Vector3D)
endfunction
`==============================================
`
`==============================================
function CX_3D_LinePlane(ln as Line3D, p as Plane)
endfunction
`==============================================
`Returns the distance between a point(p) and
`a plane(pn)
`This tests against an infinte plane
`==============================================
function CX_3D_DistancePointPlane#(p as Vector3D, pn as Plane)
num# = pn.n.x*(p.x-pn.p.x) + pn.n.y*(p.y-pn.p.y) + pn.n.z*(p.z-pn.p.z)
den# = sqrt(pn.n.x*pn.n.x + pn.n.y*pn.n.y + pn.n.z*pn.n.z)
n# = num# / den#
endfunction n#
`==============================================
`Returns 1 if the ellipse(e) intersects line(ln)
`0 if not
`Converts the problem into a circle/line intersection
`by transforming the space so that the ellipse
`becomes a unit circle
`==============================================
function CX_2D_EllipseLine(e as Ellipse2D, ln as Line2D)
ln.a.x = ln.a.x / e.radius.x
ln.a.y = ln.a.y / e.radius.y
ln.b.x = ln.b.x / e.radius.x
ln.b.y = ln.b.y / e.radius.y
c as Circle2D
c.center.x = e.center.x / e.radius.x
c.center.y = e.center.y / e.radius.y
c.radius = 1
n = CX_2D_CircleLine(c, ln)
endfunction n
`==============================================
`Returns 1 if the circle(c) intersects line(ln)
`0 if not
`==============================================
function CX_2D_CircleLine(c as Circle2D, ln as Line2D)
d# = CX_2D_DistancePointLine#(c.center, ln)
if d# <= c.radius then exitfunction 1
endfunction 0
`==============================================
`Returns 1 if point is inside capsule, 0 if not
`==============================================
function CX_2D_PointCapsule(p as Vector2D, c as Capsule2D)
if CX_2D_DistancePointLine#(p, c.ln) <= c.radius then exitfunction 1
endfunction 0
`==============================================
`Returns the distance between point(P) and
`the line segment(LN). If the point is beyond
`the line's endpoints, then the distance returned
`is that of the point from the nearest endpoint.
`In other words, this does not test an infinte line
`==============================================
function CX_2D_DistancePointLine#(p as Vector2D, ln as Line2D)
n# = (p.x-ln.a.x)*(ln.b.x-ln.a.x) + (p.y-ln.a.y)*(ln.b.y-ln.a.y)
x# = ln.b.x - ln.a.x
y# = ln.b.y - ln.a.y
d# = x#*x# + y#*y#
u# = n# / d#
dist# = 0.0
if u# >= 0 AND u# <= 1
i as Vector2D
i.x = ln.a.x + u#*(ln.b.x-ln.a.x)
i.y = ln.a.y + u#*(ln.b.y-ln.a.y)
dist# = CX_2D_lineLength#(p,i)
else
if u# < 0 then dist# = CX_2D_lineLength#(p,ln.a)
if u# > 1 then dist# = CX_2D_lineLength#(p,ln.b)
endif
endfunction dist#
`==============================================
`Returns the distance between two 2D points
`==============================================
function CX_2D_LineLength#(a as Vector2D, b as Vector2D)
x# = b.x - a.x
y# = b.y - a.y
d# = sqrt(x#*x# + y#*y#)
endfunction d#
`==============================================
`Returns 1 if point is inside triangle, 0 if not
`Point (px,py)
`triangle (x1,y1),(x2,y2),(x3,y3)
`==============================================
function CX_2D_PointTriangle(px as float, py as float, x1 as float,y1 as float,x2 as float,y2 as float,x3 as float,y3 as float)
dABx = x2-x1
dABy = y2-y1
dBCx = x3-x2
dBCy = y3-y2
rem if verts are clockwise
if (dABx*dBCy - dABy*dBCx) < 0
if dABx*(py-y1) >= dABy*(px-x1) then exitfunction 0
if dBCx*(py-y2) >= dBCy*(px-x2) then exitfunction 0
if (x1-x3)*(py-y3) >= (y1-y3)*(px-x3) then exitfunction 0
rem verts are ccw
else
if dABx*(py-y1) < dABy*(px-x1) then exitfunction 0
if dBCx*(py-y2) < dBCy*(px-x2) then exitfunction 0
if (x1-x3)*(py-y3) < (y1-y3)*(px-x3) then exitfunction 0
endif
rem point is inside triangle
endfunction 1
`==============================================
`Returns 1 if boxes overlap, 0 if not
`upper left corner of box A (x1,y1) and width(w1)
`and height(h1)
`upper left corner of box B (x2,y2) and width(w2)
`and height(h2)
`==============================================
function CX_2D_AABB(x1 as float,y1 as float,w1 as float,h1 as float,x2 as float,y2 as float,w2 as float,h2 as float)
if x1 < (x2+w2) and (x1+w1) > x2 and y1 < (y2+h2) and y2 < (y1+h2) then exitfunction 1
endfunction 0
`==============================================
`Returns 1 if circles are overlapping, 0 if not
`Center of circle A (x1,y1), radius (r1)
`Center of circle B (x2,y2), radius (r2)
`==============================================
function CX_2D_CircleCircle(x1 as float, y1 as float r1 as float, x2 as float, y2 as float, r2 as float)
dsqr# = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)
rsqr# = (r1+r2)*(r1+r2)
if dsqr# <= rsqr# then exitfunction 1
endfunction 0
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