1 /**

     2  * test/demos/pmc/surface.cc

     3  * Copyright (C) 2008 Markus Broeker

     4  */

     5 

     6 #include <surface.h>

     7 

     8 #define max(a,b) (((a) > (b)) ? (a) : (b))

     9 #define min(a,b) (((a) < (b)) ? (a) : (b))

    10 #define abs(a) (((a)<0) ? -(a) : (a))

    11 #define sign(a) (((a)<0) ? -1 : (a)>0 ? 1 : 0)

    12 

    13 Surface::Surface (int w, int h, int d)

    14 {

    15     width = w;

    16     height = h;

    17     depth = d;

    18 

    19     SDL_Init (SDL_INIT_VIDEO);

    20     screen = SDL_SetVideoMode (width, height, depth, SDL_HWSURFACE);

    21     red = SDL_MapRGB (screen->format, 0xff, 0x00, 0x00);

    22     black = SDL_MapRGB (screen->format, 0x00, 0x00, 0x00);

    23 

    24     color = red;

    25 }

    26 

    27 Surface::~Surface ()

    28 {

    29     SDL_Quit ();

    30 }

    31 

    32 void Surface::drawPixel (int x, int y)

    33 {

    34     if (SDL_MUSTLOCK (screen)) {

    35         if (SDL_LockSurface (screen) < 0) {

    36             return;

    37         }

    38     }

    39 

    40     switch (screen->format->BytesPerPixel) {

    41     case 1:{                   /* vermutlich 8 Bit */

    42             Uint8 *bufp;

    43 

    44             bufp = (Uint8 *) screen->pixels + y * screen->pitch + x;

    45             *bufp = color;

    46         }

    47         break;

    48 

    49     case 2:{                   /* vermutlich 15 Bit oder 16 Bit */

    50             Uint16 *bufp;

    51 

    52             bufp = (Uint16 *) screen->pixels + y * screen->pitch / 2 + x;

    53             *bufp = color;

    54         }

    55         break;

    56 

    57     case 3:{                   /* langsamer 24-Bit-Modus, selten verwendet */

    58             Uint8 *bufp;

    59 

    60             bufp = (Uint8 *) screen->pixels + y * screen->pitch + x * 3;

    61             if (SDL_BYTEORDER == SDL_LIL_ENDIAN) {

    62                 bufp[0] = color;

    63                 bufp[1] = color >> 8;

    64                 bufp[2] = color >> 16;

    65             } else {

    66                 bufp[2] = color;

    67                 bufp[1] = color >> 8;

    68                 bufp[0] = color >> 16;

    69             }

    70         }

    71         break;

    72 

    73     case 4:{                   /* vermutlich 32 Bit */

    74             Uint32 *bufp;

    75 

    76             bufp = (Uint32 *) screen->pixels + y * screen->pitch / 4 + x;

    77             *bufp = color;

    78         }

    79         break;

    80     }

    81 

    82     if (SDL_MUSTLOCK (screen)) {

    83         SDL_UnlockSurface (screen);

    84     }

    85 }

    86 

    87 void Surface::drawLine (int x1, int y1, int x2, int y2)

    88 {

    89     int d;

    90     int x;

    91     int y;

    92     int ax;

    93     int ay;

    94     int sx;

    95     int sy;

    96     int dx;

    97     int dy;

    98 

    99     Uint8 *lineAddr;

   100     Sint32 yOffset;

   101 

   102     /*

   103      * SANITY CHECK: fix segfault in *((Uint16 *) (lineAddr + (x << 1))) = (Uint16) color;

   104      */

   105     if (y1 < 0 || y2 < 0)

   106         return;

   107 

   108     if (x1 < 0 || x2 < 0)

   109         return;

   110 

   111     dx = x2 - x1;

   112     ax = abs (dx) << 1;

   113     sx = sign (dx);

   114 

   115     dy = y2 - y1;

   116     ay = abs (dy) << 1;

   117     sy = sign (dy);

   118     yOffset = sy * screen->pitch;

   119 

   120     x = x1;

   121     y = y1;

   122 

   123     lineAddr = ((Uint8 *) screen->pixels) + (y * screen->pitch);

   124     if (ax > ay) {              /* x dominant */

   125         d = ay - (ax >> 1);

   126         for (;;) {

   127             *((Uint16 *) (lineAddr + (x << 1))) = (Uint16) color;

   128 

   129             if (x == x2) {

   130                 return;

   131             }

   132             if (d >= 0) {

   133                 y += sy;

   134                 lineAddr += yOffset;

   135                 d -= ax;

   136             }

   137             x += sx;

   138             d += ay;

   139         }

   140     } else {                    /* y dominant */

   141         d = ax - (ay >> 1);

   142         for (;;) {

   143             *((Uint16 *) (lineAddr + (x << 1))) = (Uint16) color;

   144 

   145             if (y == y2) {

   146                 return;

   147             }

   148             if (d >= 0) {

   149                 x += sx;

   150                 d -= ay;

   151             }

   152             y += sy;

   153             lineAddr += yOffset;

   154             d += ax;

   155         }

   156     }

   157 }

   158 

   159 void Surface::flip ()

   160 {

   161     SDL_Flip (screen);

   162 }

   163 

   164 void Surface::setColor (foregroundColor c)

   165 {

   166     switch (c) {

   167     case BLACK:

   168         color = black;

   169         break;

   170     case RED:

   171         color = red;

   172         break;

   173     };

   174 }