collide.h

#pragma once
#include "types.h"

// useful macro for encoding single bits
#define BIT( X ) (1<<(X))

// map bit codes
const uint8 cQUpper  = BIT( 0 ); // can push up
const uint8 cQLower  = BIT( 1 ); // can push down
const uint8 cQLeft   = BIT( 2 ); // can push left
const uint8 cQRight  = BIT( 3 ); // can push right
const uint8 cWall    = BIT( 7 ); // is a wall

//
struct sCollideMap
{
    // map size and scale
    uint32  width, height;
    uint32  tileSize;
    // tile data encoded as above
    uint8  *data;
};

//
struct sCollideObject
{
    // rectangle area
    sint32 x1, y1, x2, y2;
    // resolution vector
    sint32 r_x, r_y;
};

// check for a collision between and object and the map
extern bool collide_test
(
    sCollideMap    *map,
    sCollideObject *object
);

// preprocess a map with bit encoded gradients
extern void collide_preprocess
(
    sCollideMap *map
);