View source for OBD:PLEA

{{OBD_File_Header | type=PLEA | prev=OTLF | next=PNTA | name=Plane Equation Array | family=Level | align=center}}


[[image:plea_a.gif]]


{{Table}}
{{OBDth}}
{{OBDtr| 0x00 | res_id   |FF0000| 01 41 02 00 | 577   | 00577-.PLEA }}
{{OBDtr| 0x04 | lev_id   |FFFF00| 01 00 00 06 | 3     | level 3 }}
{{OBDtr| 0x08 | char[20] |00FF00| AD DE       | dead  | unused }}
{{OBDtr| 0x1C | int32    |00FFFF| 03 00 00 00 | 13554 | array size }}
{{OBDtrBK}}
{{OBDtr| 0x00 | float    |FFC8C8| 00 00 00 00 | 0.000000 | 'a' coefficient of the plane equation (x component of plane's normal) }}
{{OBDtr| 0x04 | float    |FFFFC8| 00 00 00 00 | 0.000000 | 'b' coefficient of the plane equation (y component of plane's normal) }}
{{OBDtr| 0x08 | float    |C8FFC8| 00 00 80 3F | 1.000000 | 'c' coefficient of the plane equation (z component of plane's normal) }}
{{OBDtr| 0x0C | float    |C8FFFF| 00 00 19 44 |612.000000| 'd' coefficient of the plane equation }}
|}


;Plane equation
:The canonical equation for a [http://mathworld.wolfram.com/Plane.html plane] in 3D is :
::a * x + b * y + c * z + d = 0
:where (a, b, c, d) are 4 real numbers. The plane is the set of points (x, y, z) verifying that equation.
:The four floats in one of a PLEA's packages are exactly the (a, b, c, d) of the above definition.
::In that case, the first package of the above example defines the plane (0 * x + 0 * y + 1 * z + 612 = 0), i.e., the vertical plane z = -612.
Planes are used for environment culling and collision detection.
{{OBD_File_Footer | type=PLEA | prev=OTLF | next=PNTA | name=Plane Equation Array | family=Level}}