include/pmask.h

   1 #ifndef pmask_H
   2 #define pmask_H
   3
   4 /*
   5 This is the Pixel MASK library, which does pixel-perfect collisions using
   6 bit masks.
   7
   8 There are several configuration options here, hope they aren't too
   9 confusing.
  10 */
  11
  12 #define PMASK_VERSION          1
  13
  14 #define USE_ALLEGRO
  15 //#define USE_SDL
  16
  17 #ifdef USE_ALLEGRO
  18 struct BITMAP;
  19 #endif
  20 #ifdef USE_SDL
  21 struct SDL_Surface;
  22 #endif
  23
  24 #ifdef __cplusplus
  25 #define pmask_USE_INLINE
  26 extern "C" {
  27 #endif
  28
  29 //This is the bounding box collision detection macro.
  30 //It is a general purpose macro. Pass it the coordinates of one rectangle and the width and
  31 //height of it, then pass the coordinates of a second rectangle and the width and height of
  32 //it. It will return 0 if theres not collision or 1 if there is a collision between the
  33 //rectangles (the rectangles overlap).
  34 //This macro works looking for out of range values, if some value is out of
  35 //range it returns 0, if all the values are in range it returns true.
  36 #define check_bb_collision_general(x1,y1,w1,h1,x2,y2,w2,h2) (!( ((x1)>=(x2)+(w2)) || ((x2)>=(x1)+(w1)) || ((y1)>=(y2)+(h2)) || ((y2)>=(y1)+(h1)) ))
  37 #define check_bb_collision(mask1,mask2,x1,y1,x2,y2) check_bb_collision_general(x1,y1,mask1->w,mask1->h,x2,y2,mask2->w,mask2->h)
  38
  39 //MASK_WORD_TYPE and MASK_WORD_BITBITS can be changed for your platform
  40
  41 //MASK_WORD_TYPE should be the largest fast integer type available
  42 #define MASK_WORD_TYPE unsigned long int
  43
  44 //MASK_WORD_BITBITS should be the log base 2
  45 //of the number of bits in MASK_WORD_TYPE
  46 //e.g. 4 for 16-bit ints, 5 for 32-bit ints, 6 for 64-bit ints
  47 #if defined(__alpha__) || defined(__ia64__) || defined(__x86_64__)
  48 #define MASK_WORD_BITBITS 6
  49 #else
  50 #define MASK_WORD_BITBITS 5
  51 #endif
  52
  53 //if SINGLE_MEMORY_BLOCK is defined
  54 //then each mask will be allocated as
  55 //only a single memory block.
  56 //this means that masks will (in theory)
  57 //be ever-so-slightly faster and more memory efficient
  58 //however, if in single memory block mode
  59 //then the masks are variable-sized
  60 //so you can not use an array of them
  61 //#define MASK_SINGLE_MEMORY_BLOCK
  62
  63 typedef struct PMASK
  64 {
  65         short int w;//width
  66         short int h;//height
  67 #ifdef MASK_SINGLE_MEMORY_BLOCK
  68         MASK_WORD_TYPE mask[1];//mask data (single memory block)
  69 #else
  70         MASK_WORD_TYPE *mask;//mask data (pointer at second memory block)
  71 #endif
  72 } PMASK;
  73
  74 void install_pmask(); //sets up library
  75
  76 int check_pmask_collision(struct PMASK *mask1, struct PMASK *mask2, int x1, int y1, int x2, int y2); //checks for collision (0 = no collision, 1 = collision)
  77
  78 int get_pmask_pixel(struct PMASK *mask, int x, int y) ; //returns 0 if mask is clear at those coordinates, 1 if not clear
  79 void set_pmask_pixel(struct PMASK *mask, int x, int y, int value) ;//makes mask clear at those coordinates if value is zero, others makes mask not-clear at those coordinates
  80
  81 void init_pmask        (struct PMASK *mask, int w, int h); //initializes a PMASK
  82 void pmask_load_pixels (struct PMASK *mask, void *pixels, int pitch, int bytes_per_pixel, int trans_color);//loads a pmask with pixel data from memory
  83 void pmask_load_func   (struct PMASK *mask, int x, int y, void *surface, int trans_color, int (*func)(void*,int,int));//loads a pmask with pixel data from a function
  84 void deinit_pmask(PMASK *mask);//de-initializes a pmask
  85
  86 PMASK *create_pmask  (int w, int h);//creates a new pmask and initializes it
  87 void destroy_pmask(struct PMASK *mask);//destroys a pmask created by create_pmask
  88
  89 #if defined USE_ALLEGRO
  90 void init_allegro_pmask(struct PMASK *mask, struct BITMAP *sprite);
  91 PMASK *create_allegro_pmask(struct BITMAP *sprite);
  92 #endif
  93
  94 #if defined USE_SDL
  95 void init_sdl_pmask(struct PMASK *mask, struct SDL_Surface *sprite, int trans_color);
  96 PMASK *create_sdl_pmask(struct SDL_Surface *sprite, int trans_color);
  97 #endif
  98
  99 #ifdef __cplusplus
 100 }
 101 #endif
 102
 103 #define MASK_WORD_SIZE sizeof(MASK_WORD_TYPE)
 104 #define MASK_WORD_BITS (MASK_WORD_SIZE*8)
 105
 106 #if defined pmask_USE_INLINED
 107 inline int _get_pmask_pixel(struct PMASK *mask, int x, int y) {
 108         //no bounds checking
 109         return 1 & (mask->mask[(mask->h * (x >> MASK_WORD_BITBITS)) + y] >> (x & (MASK_WORD_BITS-1)));
 110 }
 111 inline void _set_pmask_pixel(struct PMASK *mask, int x, int y, int value) {
 112         //no bounds checking
 113         if (value) {
 114                 mask->mask[(mask->h * (x >> MASK_WORD_BITBITS)) + y] |= 1 << (x & (MASK_WORD_BITS-1));
 115         } else {
 116                 mask->mask[(mask->h * (x >> MASK_WORD_BITBITS)) + y] &=~(1 << (x & (MASK_WORD_BITS-1)));
 117         }
 118 }
 119 #else
 120 #define _get_pmask_pixel get_pmask_pixel
 121 #define _set_pmask_pixel set_pmask_pixel
 122 #endif
 123
 124
 125 #endif          /* ifndef PPCOL_H */
 126