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Collision Flags
Collision flags are what haxball's physics uses to determine which objects collide and which objects ignore each other.
Each flag represents a group or category.
This is the default collision group of the ball.
This layer is automatically added to players of the red team.
This layer is automatically added to players of the blue team.
This layer represents kickoff barriers that become active during kickOff for the red team.
This layer represents kickoff barriers that become active during kickOff for the blue team.
This is the default collision group for vertexes segments and planes.
Represents a set including ball, red, blue, redKO, blueKO and wall
Objects with this flag in their cGroup will become kickable by the players.
Objects with this flag in their cGroup will score goals if they cross a goal line.
Has no special meaning and can be used for any purpose
Has no special meaning and can be used for any purpose
Has no special meaning and can be used for any purpose
Has no special meaning and can be used for any purpose
Physical objects like discs vertexes segments and planes have two sets of flags: cGroup and cMask.
cGroup stands for collision group. With this property an object expresses which groups it belongs to. For example, normally players belong to the "blue" or "red" groups while segments and vertexes use the "wall" group by default.
cMask stands for collision mask. This property expresses which groups an object can collide with. Usually this is set to "all" meaning it can collide with almost any other object.
Object A and B will collide if and only if the intersection of A.cGroup and B.cMask is not empty AND the intersection of B.cGroup and A.cMask is not empty.
Haxball expresses collision groups and mask as Bit Fields in the Headless Host API.
In javascript the collision logic can be expressed as:
(objA.cGroup & objB.cMask!= 0) && (objB.cGroup & objA.cMask != 0)Do not confuse & operator with &&, the former is a bitwise operator while the latter is boolean.
Player's cMask is always set to ball, red, blue and wall.
During kickOff players will also have redKO or blueKO in their cMask depending on which team the kickoff belongs to.
It is not possible to modify a player's cMask (but it is possible to modify it's cGroup)
In .hbs files collision flags are defined as an array of strings where each string is the name of a flag.
Example: "cMask": ["red", "blue", "redKO", "ball", "c1"]
The all flag can be combined with other flags to form an union. Example: "cMask": ["all", "c0", "c2"].