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 #define MASK_WORD_BITBITS 5
  48
  49
  50 //if SINGLE_MEMORY_BLOCK is defined
  51 //then each mask will be allocated as
  52 //only a single memory block.
  53 //this means that masks will (in theory)
  54 //be ever-so-slightly faster and more memory efficient
  55 //however, if in single memory block mode
  56 //then the masks are variable-sized
  57 //so you can not use an array of them
  58 //#define MASK_SINGLE_MEMORY_BLOCK
  59
  60 typedef struct PMASK
  61 {
  62         short int w;//width
  63         short int h;//height
  64 #ifdef MASK_SINGLE_MEMORY_BLOCK
  65         MASK_WORD_TYPE mask[1];//mask data (single memory block)
  66 #else
  67         MASK_WORD_TYPE *mask;//mask data (pointer at second memory block)
  68 #endif
  69 } PMASK;
  70
  71 void install_pmask(); //sets up library
  72
  73 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)
  74
  75 int get_pmask_pixel(struct PMASK *mask, int x, int y) ; //returns 0 if mask is clear at those coordinates, 1 if not clear
  76 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
  77
  78 void init_pmask        (struct PMASK *mask, int w, int h); //initializes a PMASK
  79 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
  80 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
  81 void deinit_pmask(PMASK *mask);//de-initializes a pmask
  82
  83 PMASK *create_pmask  (int w, int h);//creates a new pmask and initializes it
  84 void destroy_pmask(struct PMASK *mask);//destroys a pmask created by create_pmask
  85
  86 #if defined USE_ALLEGRO
  87 void init_allegro_pmask(struct PMASK *mask, struct BITMAP *sprite);
  88 PMASK *create_allegro_pmask(struct BITMAP *sprite);
  89 #endif
  90
  91 #if defined USE_SDL
  92 void init_sdl_pmask(struct PMASK *mask, struct SDL_Surface *sprite, int trans_color);
  93 PMASK *create_sdl_pmask(struct SDL_Surface *sprite, int trans_color);
  94 #endif
  95
  96 #ifdef __cplusplus
  97 }
  98 #endif
  99
 100 #define MASK_WORD_SIZE sizeof(MASK_WORD_TYPE)
 101 #define MASK_WORD_BITS (MASK_WORD_SIZE*8)
 102
 103 #if defined pmask_USE_INLINED
 104 inline int _get_pmask_pixel(struct PMASK *mask, int x, int y) {
 105         //no bounds checking
 106         return 1 & (mask->mask[(mask->h * (x >> MASK_WORD_BITBITS)) + y] >> (x & (MASK_WORD_BITS-1)));
 107 }
 108 inline void _set_pmask_pixel(struct PMASK *mask, int x, int y, int value) {
 109         //no bounds checking
 110         if (value) {
 111                 mask->mask[(mask->h * (x >> MASK_WORD_BITBITS)) + y] |= 1 << (x & (MASK_WORD_BITS-1));
 112         } else {
 113                 mask->mask[(mask->h * (x >> MASK_WORD_BITBITS)) + y] &=~(1 << (x & (MASK_WORD_BITS-1)));
 114         }
 115 }
 116 #else
 117 #define _get_pmask_pixel get_pmask_pixel
 118 #define _set_pmask_pixel set_pmask_pixel
 119 #endif
 120
 121
 122 #endif          /* ifndef PPCOL_H */
 123