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Guide to Game Development/Theory/Collision detection/Circular

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Circle, Circle Collision Detection

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This the collision detection to check if two circles are colliding. This method can be directly applied to two spheres.

For this example we'll need to define some example variables:

- The origin as a null position vector.

- Circle 1's centre as a position vector.

- Circle 2's centre as a position vector.

- Circle 1's radius as a decimal number.

- Circle 1's radius as a decimal number.

Collision test

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If  then:
    They are not colliding.
If  then:
    They are touching.
If  then:
    They are colliding.

if you wish to treat 'touching' as 'colliding', then use the following:

If  then:
    They are not colliding.
If  then:
    They are colliding.

Circle, Point Collision Detection

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This is basically a simplified version of the one above, this is because you can treat a point like a circle with no radius.

For this example we'll need to define some example variables:

- The origin as a null position vector.

- The point's location as a position vector.

- Circle 1's centre as a position vector.

- The Circle's radius as a decimal number.

Collision test

[edit | edit source]
If  then:
    They are not colliding.
If  then:
    They are touching.
If  then:
    They are colliding.

if you wish to treat 'touching' as 'colliding', then use the following:

If  then:
    They are not colliding.
If  then:
    They are colliding.


Circle, Line collision detection

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Circle, Rectangle Collision Detection

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Youtube:

Covers "Circle, Circle" and "Circle, Point"

References

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