colliders.h File Reference

Defines the collider system for collision detection. More...

#include <SDL.h>
#include <stdbool.h>

Go to the source code of this file.

Classes
struct	Collider
	This struct represents a collider. More...
struct	ColliderCheckResult

Macros
#define	MAX_COLLISIONS_PER_CHECK   20
#define	MAX_COLLIDABLES   1024

Typedefs
typedef struct Collider	Collider
	This struct represents a collider.
typedef struct ColliderCheckResult	ColliderCheckResult

Enumerations
enum	CollisionLayer {   COLLISION_LAYER_NONE = 0 , COLLISION_LAYER_PLAYER = 1 << 0 , COLLISION_LAYER_ENVIRONMENT = 1 << 1 , COLLISION_LAYER_ENEMY = 1 << 2 ,   COLLISION_LAYER_TRIGGER = 1 << 3 , COLLISION_LAYER_ENEMY_PROJECTILE = 1 << 4 , COLLISION_LAYER_PLAYER_PROJECTILE = 1 << 5 }

Functions
void	Collider_Start ()
	Initialize the collision manager.
void	Collider_Register (Collider *collidable, void *owner)
	Register a collider with the collision manager.
bool	Collider_Check (Collider *collidableObject, ColliderCheckResult *result)
	Check for collisions with a collider.
void	Collider_Reset (Collider *collider)
	Deactivates a collider.

Variables
Collider *	ColliderList [MAX_COLLIDABLES]
int	ColliderCount

Detailed Description

Defines the collider system for collision detection.

This file contains the declarations for the collision manager. The collision manager is responsible for detecting collisions between entities in the game.

Author

Mango, Tony and Darren

Date

2025-03-09

Usage Examples

TLDR: Create Collider struct somewhere, register it, check for collisions, and handle the collisions.

Step 1: Create a collider struct for your entity. <br>

Note: the collider needs to be stored in a memory that's reusable. (i.e static/global variables)

Example:

// Static variables
static Collider playerCollider = {
    // (If you're making the hitbox follow something, only the last two values (width and height) matter)
    .hitbox = {0, 0, 20, 20}, 
    .layer = COLLISION_LAYER_PLAYER,
    .collidesWith = COLLISION_LAYER_ENVIRONMENT 
                  | COLLISION_LAYER_ENEMY,
};
 
// Global variables (View PlayerData struct and player variable)
player.state.collider = {
    .hitbox = {0, 0, 20, 20}, 
    .layer = COLLISION_LAYER_PLAYER,
    .collidesWith = COLLISION_LAYER_ENVIRONMENT 
                  | COLLISION_LAYER_ENEMY,
};

This collider will check for collision with environment and enemies.

Step 2: Register the collider

Register the collider with the collision manager:

Example:

Collider_Register(&playerCollider, &player);

This will add the collider to the list of colliders that the collision manager checks.

Step 3: Check for collisions

Check for collisions with the collider:

Example:

ColliderCheckResult result;
Collider_Check(&playerCollider, &result);

This will check for collisions with the collider and store the results in the result struct. After that, you can do something with the detected collisions:

for (int i = 0; i < result.count; i++) {
    Collider* collisionObject = result.objects[i];
    // Do something with the collision object
    switch(collisionObject->layer) {
        case COLLISION_LAYER_ENVIRONMENT:
            // Handle collision with environment, for example stopping movement
            break;
        case COLLISION_LAYER_ENEMY:
            // Handle collision with enemy, for example taking damage
            break;
    }
}

Macro Definition Documentation

MAX_COLLIDABLES

#define MAX_COLLIDABLES   1024

MAX_COLLISIONS_PER_CHECK

#define MAX_COLLISIONS_PER_CHECK   20

Typedef Documentation

Collider

typedef struct Collider Collider

This struct represents a collider.

A collider is a hitbox that can be used to detect collisions between objects. It is used to detect collisions between entities in the game.

Todo:

Add a system to follow/attach colliders to entities.

ColliderCheckResult

typedef struct ColliderCheckResult ColliderCheckResult

Enumeration Type Documentation

CollisionLayer

enum CollisionLayer

Enumerator
COLLISION_LAYER_NONE
COLLISION_LAYER_PLAYER
COLLISION_LAYER_ENVIRONMENT
COLLISION_LAYER_ENEMY
COLLISION_LAYER_TRIGGER
COLLISION_LAYER_ENEMY_PROJECTILE
COLLISION_LAYER_PLAYER_PROJECTILE

Function Documentation

Collider_Check()

bool Collider_Check	(	Collider *	collider,
		ColliderCheckResult *	checkResult
	)

Check for collisions with a collider.

Parameters

collidableObject	The collider to check
result	Where to store the collision results

Returns

true if any collisions were detected

Check for collisions with a collider.

This function checks for collision between a collider and everything else in the ColliderList array. Any colliders whose layer is not in the input collider's collidesWith section will be ignored.

Parameters

collider	The input collider
checkResult	The checkResult of the collider, which includes 2 members: checkResult.objects: an array of detected colliders checkResult.count: number of collisions detected

Returns

true if collision detected, false otherwise

Collider_Register()

void Collider_Register	(	Collider *	collider,
		void *	owner
	)

Register a collider with the collision manager.

Parameters

collidable	The collider to register
owner	The entity that owns this collider

Register a collider with the collision manager.

This is so that every colliders can be checked by each other.

Parameters

collider	A pointer to the collider struct. For example: &player.state.collider
owner	A pointer to the owner of the collider. For example: &player

Collider_Reset()

void Collider_Reset

(

Collider *

collider

)

Deactivates a collider.

Parameters

collider

The collider to deactivate

Deactivates a collider.

Parameters

collider

The collider to reset

Collider_Start()

void Collider_Start

(

)

Initialize the collision manager.

Initialize the collision manager.

Variable Documentation

ColliderCount

int ColliderCount

extern

ColliderList

Collider* ColliderList[MAX_COLLIDABLES]

extern