i dunno if this will be of any use to anyone, just made it for fun in like 30 mins this morning cuz i wanted to use matrices manualy (dunno why :P). But yea here it is 2 dimensional bounding box code, they can be rotated scaled positioned drawn and of course intercected for collisions...
;Matrix Codes
Const MATRIX_ALL = 0000
Const MATRIX_TRANSLATION = 0001
Const MATRIX_ROTATION = 0002
Const MATRIX_SCALE = 0003
;Bounding Box Type
Type BBox2D
Field x1,y1
Field x2,y2
Field x3,y3
Field x4,y4
Field PosMat.Matrix2D
Field RotMat.Matrix2D
Field ScaleMat.Matrix2D
End Type
;Matrix Type
Type Matrix2D
Field v00#,v10#,v20#,v01#,v11#,v21#,v02#,v12#,v22#
End Type
;function to create a 2d bounding box
Function CreateBBox2D(x1,y1,x2,y2)
b.BBox2D = New BBox2D
b\PosMat = New Matrix2D
b\RotMat = New Matrix2D
b\ScaleMat = New Matrix2D
b\x1 = x1
b\y1 = y1
b\x2 = x2
b\y2 = y1
b\x3 = x2
b\y3 = y2
b\x4 = x1
b\y4 = y2
ResetBBox2DMatrix(Handle(b),0000)
Return Handle(b)
End Function
;function to position a bounding box
Function PositionBBox2D(h,x,y)
b.BBox2D = Object.BBox2D(h)
SetBBox2DMatrix(b\PosMat,1,0,x,0,1,y,0,0,1)
End Function
;function to rotate a bounding box
Function RotateBBox2D(h,angle#)
b.BBox2D = Object.BBox2D(h)
SetBBox2DMatrix(b\RotMat,Cos(angle#),Sin(angle#),0,-Sin(angle#),Cos(angle#),0,0,0,1)
End Function
;function to scale a bounding box
Function ScaleBBox2D(h,sx,sy)
b.BBox2D = Object.BBox2D(h)
SetBBox2DMatrix(b\ScaleMat,sx,0,0,0,sy,0,0,0,1)
End Function
;funciton to draw bounding boxes
Function DrawBBox2D(h)
b.BBox2D = Object.BBox2D(h)
Matrix.Matrix2D = New Matrix2D
SetBBox2DMatrix(Matrix,b\RotMat\v00,b\RotMat\v10,b\PosMat\v20,b\RotMat\v01,b\RotMat\v11,b\PosMat\v21,0,0,1)
MultBBox2DMatrix(Matrix,b\ScaleMat\v00,0,0,0,b\ScaleMat\v11,0,0,0,1)
vx1 = b\x1*Matrix\v00 + b\y1*Matrix\v10 + Matrix\v20
vy1 = b\x1*Matrix\v01 + b\y1*Matrix\v11 + Matrix\v21
vx2 = b\x2*Matrix\v00 + b\y2*Matrix\v10 + Matrix\v20
vy2 = b\x2*Matrix\v01 + b\y2*Matrix\v11 + Matrix\v21
vx3 = b\x3*Matrix\v00 + b\y3*Matrix\v10 + Matrix\v20
vy3 = b\x3*Matrix\v01 + b\y3*Matrix\v11 + Matrix\v21
vx4 = b\x4*Matrix\v00 + b\y4*Matrix\v10 + Matrix\v20
vy4 = b\x4*Matrix\v01 + b\y4*Matrix\v11 + Matrix\v21
Line vx1,vy1,vx2,vy2
Line vx2,vy2,vx3,vy3
Line vx3,vy3,vx4,vy4
Line vx4,vy4,vx1,vy1
Delete Matrix
End Function
;function to test for intercections between bounding boxes
Function BBoxesIntersect(hb1,hb2)
b1.BBox2D = Object.BBox2D(hb1)
Matrix.Matrix2D = New Matrix2D
SetBBox2DMatrix(Matrix,b1\RotMat\v00,b1\RotMat\v10,b1\PosMat\v20,b1\RotMat\v01,b1\RotMat\v11,b1\PosMat\v21,0,0,1)
MultBBox2DMatrix(Matrix,b1\ScaleMat\v00,0,0,0,b1\ScaleMat\v11,0,0,0,1)
vx11 = b1\x1*Matrix\v00 + b1\y1*Matrix\v10 + Matrix\v20
vy11 = b1\x1*Matrix\v01 + b1\y1*Matrix\v11 + Matrix\v21
vx12 = b1\x2*Matrix\v00 + b1\y2*Matrix\v10 + Matrix\v20
vy12 = b1\x2*Matrix\v01 + b1\y2*Matrix\v11 + Matrix\v21
vx13 = b1\x3*Matrix\v00 + b1\y3*Matrix\v10 + Matrix\v20
vy13 = b1\x3*Matrix\v01 + b1\y3*Matrix\v11 + Matrix\v21
vx14 = b1\x4*Matrix\v00 + b1\y4*Matrix\v10 + Matrix\v20
vy14 = b1\x4*Matrix\v01 + b1\y4*Matrix\v11 + Matrix\v21
b2.BBox2D = Object.BBox2D(hb2)
SetBBox2DMatrix(Matrix,b2\RotMat\v00,b2\RotMat\v10,b2\PosMat\v20,b2\RotMat\v01,b2\RotMat\v11,b2\PosMat\v21,0,0,1)
MultBBox2DMatrix(Matrix,b2\ScaleMat\v00,0,0,0,b2\ScaleMat\v11,0,0,0,1)
vx21 = b2\x1*Matrix\v00 + b2\y1*Matrix\v10 + Matrix\v20
vy21 = b2\x1*Matrix\v01 + b2\y1*Matrix\v11 + Matrix\v21
vx22 = b2\x2*Matrix\v00 + b2\y2*Matrix\v10 + Matrix\v20
vy22 = b2\x2*Matrix\v01 + b2\y2*Matrix\v11 + Matrix\v21
vx23 = b2\x3*Matrix\v00 + b2\y3*Matrix\v10 + Matrix\v20
vy23 = b2\x3*Matrix\v01 + b2\y3*Matrix\v11 + Matrix\v21
vx24 = b2\x4*Matrix\v00 + b2\y4*Matrix\v10 + Matrix\v20
vy24 = b2\x4*Matrix\v01 + b2\y4*Matrix\v11 + Matrix\v21
If LinesIntersect(vx11,vy11,vx12,vy12,vx21,vy21,vx22,vy22) Then Return True
If LinesIntersect(vx11,vy11,vx12,vy12,vx22,vy22,vx23,vy23) Then Return True
If LinesIntersect(vx11,vy11,vx12,vy12,vx23,vy23,vx24,vy24) Then Return True
If LinesIntersect(vx11,vy11,vx12,vy12,vx24,vy24,vx21,vy21) Then Return True
If LinesIntersect(vx12,vy12,vx13,vy13,vx21,vy21,vx22,vy22) Then Return True
If LinesIntersect(vx12,vy12,vx13,vy13,vx22,vy22,vx23,vy23) Then Return True
If LinesIntersect(vx12,vy12,vx13,vy13,vx23,vy23,vx24,vy24) Then Return True
If LinesIntersect(vx12,vy12,vx13,vy13,vx24,vy24,vx21,vy21) Then Return True
If LinesIntersect(vx13,vy13,vx14,vy14,vx21,vy21,vx22,vy22) Then Return True
If LinesIntersect(vx13,vy13,vx14,vy14,vx22,vy22,vx23,vy23) Then Return True
If LinesIntersect(vx13,vy13,vx14,vy14,vx23,vy23,vx24,vy24) Then Return True
If LinesIntersect(vx13,vy13,vx14,vy14,vx24,vy24,vx21,vy21) Then Return True
If LinesIntersect(vx14,vy14,vx11,vy11,vx21,vy21,vx22,vy22) Then Return True
If LinesIntersect(vx14,vy14,vx11,vy11,vx22,vy22,vx23,vy23) Then Return True
If LinesIntersect(vx14,vy14,vx11,vy11,vx23,vy23,vx24,vy24) Then Return True
If LinesIntersect(vx14,vy14,vx11,vy11,vx24,vy24,vx21,vy21) Then Return True
Return False
End Function
;function to check for line to line intersections
Function LinesIntersect(x11,y11,x12,y12,x21,y21,x22,y22)
If x11=x12 Then x12 = x12+1
If x21=x22 Then x22 = x22+1
If y11=y12 Then y12 = y12+1
If y21=y22 Then y22 = y22+1
m1# = Float#((y12-y11))/Float#((x12-x11))
c1# = Float#(y11)-m1#*Float#(x11)
m2# = Float#((y22-y21))/Float#((x22-x21))
c2# = Float#(y21)-m2#*Float#(x21)
x# = Float#(c2#-c1#)/Float#(m1#-m2#)
y# = m1#*x#+c1#
If x11>x12
temp = x11
x11 = x12
x12 = temp
EndIf
If y11>y12
temp = y11
y11 = y12
y12 = temp
EndIf
If x21>x22
temp = x21
x21 = x22
x22 = temp
EndIf
If y21>y22
temp = y21
y21 = y22
y22 = temp
EndIf
If Int(x#)>=x11 And Int(x#)<=x12 And Int(y#)>=y11 And Int(y#)<=y12 And Int(x#)>=x21 And Int(x#)<=x22 And Int(y#)>=y21 And Int(y#)<=y22
Return True
EndIf
Return False
End Function
;function to reset bounding box matrixes
Function ResetBBox2DMatrix(h,matrix)
b.BBox2D = Object.BBox2D(h)
Select(matrix)
Case 0000:
SetBBox2DMatrix(b\PosMat,1,0,0,0,1,0,0,0,1)
SetBBox2DMatrix(b\RotMat,1,0,0,0,1,0,0,0,1)
SetBBox2DMatrix(b\ScaleMat,1,0,0,0,1,0,0,0,1)
Case 0001:
SetBBox2DMatrix(b\PosMat,1,0,0,0,1,0,0,0,1)
Case 0002:
SetBBox2DMatrix(b\RotMat,1,0,0,0,1,0,0,0,1)
Case 0003:
SetBBox2DMatrix(b\ScaleMat,1,0,0,0,1,0,0,0,1)
Default:
MessageBox("Error","Error: Incorrect Matrix Selection (ResetBBox2DMatrix)")
End Select
End Function
;function to Set a bounding boxes matrix
Function SetBBox2DMatrix(mat.Matrix2D,v00#,v10#,v20#,v01#,v11#,v21#,v02#,v12#,v22#)
mat\v00 = v00#
mat\v10 = v10#
mat\v20 = v20#
mat\v01 = v01#
mat\v11 = v11#
mat\v21 = v21#
mat\v02 = v02#
mat\v12 = v12#
mat\v22 = v22#
End Function
;function to multiply matrices
Function MultBBox2DMatrix(mat.Matrix2D,v00#,v10#,v20#,v01#,v11#,v21#,v02#,v12#,v22#)
mat\v00 = mat\v00*v00# + mat\v10*v01# + mat\v20*v02#
mat\v10 = mat\v00*v10# + mat\v10*v11# + mat\v20*v12#
mat\v20 = mat\v00*v20# + mat\v10*v21# + mat\v20*v22#
mat\v01 = mat\v01*v00# + mat\v11*v01# + mat\v21*v02#
mat\v11 = mat\v01*v10# + mat\v11*v11# + mat\v21*v12#
mat\v21 = mat\v01*v20# + mat\v11*v21# + mat\v21*v22#
mat\v02 = mat\v02*v00# + mat\v12*v01# + mat\v22*v02#
mat\v12 = mat\v02*v10# + mat\v12*v11# + mat\v22*v12#
mat\v22 = mat\v02*v20# + mat\v12*v21# + mat\v22*v22#
End Function
;function to equate two matrices
Function EquateBBox2DMatrices(mat1.Matrix2D,mat2.Matrix2D)
mat1\v00 =mat2\v00#
mat1\v10 =mat2\v10#
mat1\v20 =mat2\v20#
mat1\v01 =mat2\v01#
mat1\v11 =mat2\v11#
mat1\v21 =mat2\v21#
mat1\v02 =mat2\v02#
mat1\v12 =mat2\v12#
mat1\v22 =mat2\v22#
End Function
here's a small example
include "BBox2D.bb"
Graphics 640,480,32,2
SetBuffer BackBuffer()
;create two Bounding Box with the cordinates -20 to 20 on both the x and y
b = CreateBBox2D(-20,-20,20,20)
c = CreateBBox2D(-20,-20,20,20)
Color 0,255,0
;enlarge one of the bounding boxes
ScaleBBox2D b, 2,2
;position the bounding boxes
PositionBBox2D b, 205,205
PositionBBox2D c, 250,250
angle# = 0
angle2# = 0
While Not KeyDown(1)
Cls
;rotate the bounding boxes by the angles
RotateBBox2D(b,angle#)
RotateBBox2D(c,angle2#)
Color 0,255,0
;Draw The Bounding Boxes
DrawBBox2D(b)
DrawBBox2D(c)
;Check for an intersection
If BBoxesIntersect(b,c) Then Text 10,10,"INTERSECTION"
;Rotate the bounding boxes
angle# = angle# + 0.5
angle2# = angle# +0.7
Flip
Wend
if you have any questions feel free to ask
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