programs/helloWorld.c

   1 /*
   2   Simple hello world for raycastlib. Renders a single raycasted frame into
   3   terminal as ASCII.
   4
   5   author: Miloslav Ciz
   6   license: CC0 1.0, public domain
   7 */
   8
   9 #define RCL_PIXEL_FUNCTION pixelFunc /* tell the library the name of our
  10                                         function with which we write pixels to
  11                                         the screen */
  12 #define RCL_COMPUTE_FLOOR_DEPTH 0    /* turn off what we don't need, to help
  13                                         performance */
  14 #define RCL_COMPUTE_CEILING_DEPTH 0
  15
  16 #include "../raycastlib.h"           // now include raycastlib itself
  17
  18 #include <stdio.h>                   // for IO
  19
  20 #define SCREEN_W 80
  21 #define SCREEN_H 40
  22
  23 #define PIXELS_TOTAL ((SCREEN_W + 1) * SCREEN_H + 1)
  24
  25 char screen[(SCREEN_W + 1) * SCREEN_H + 1]; /* our ASCII screen, with extra
  26                                                space for newlines and
  27                                                terminating 0 */
  28
  29 /* Function that will tell the library height of square at each coordinates.
  30    We may implement it however we like, it may e.g. read the height out of a
  31    level array. Here we simply compute the height procedurally, without needing
  32    extra data. */
  33 RCL_Unit heightAt(int16_t x, int16_t y)
  34 {
  35   return (x < 0 || x > 10 || y < 0 || y > 10) ?
  36     2 * RCL_UNITS_PER_SQUARE : // two library units, imagine e.g. 2 meters
  37     0;
  38 }
  39
  40 /* This is the function we write pixels to our ASCII screen with. Above we have
  41    told the library it should call this function during rendering. */
  42 void pixelFunc(RCL_PixelInfo *p)
  43 {
  44   char c = ' ';
  45
  46   if (p->isWall)
  47   {
  48     switch (p->hit.direction)
  49     {
  50       case 1:
  51       case 2:  c = '#'; break;
  52       case 0:
  53       case 3:  c = '/'; break;
  54       default:          break;
  55     }
  56   }
  57   else // floor/ceiling
  58     c = p->isFloor ? '.' : ':';
  59
  60   screen[p->position.y * (SCREEN_W + 1) + p->position.x] = c;
  61 }
  62
  63 int main()
  64 {
  65   for (int i = 0; i < PIXELS_TOTAL; ++i) // prefill screen with newlines
  66     screen[i] = '\n';
  67
  68   screen[PIXELS_TOTAL - 1] = 0;          // terminate the string
  69
  70   RCL_Camera camera;                     // camera to specify our view
  71   RCL_initCamera(&camera);
  72
  73   // set up the camera:
  74   camera.position.x = 5 * RCL_UNITS_PER_SQUARE;
  75   camera.position.y = 6 * RCL_UNITS_PER_SQUARE;
  76   camera.direction = 5 * RCL_UNITS_PER_SQUARE / 6; // 4/5 of full angle
  77   camera.resolution.x = SCREEN_W;
  78   camera.resolution.y = SCREEN_H;
  79
  80   RCL_RayConstraints constraints;        /* this struct tell the library more
  81                                             details about how it should cast
  82                                             rays */
  83   RCL_initRayConstraints(&constraints);
  84   constraints.maxHits = 1;               // we don't need more than 1 hit here
  85   constraints.maxSteps = 40;             // max squares a ray will travel
  86
  87
  88
  89   /* This will start the rendering itself. The library will start calling our
  90      pixelFunc to render one frame. You can also try to use the complex
  91      rendering function, the result should be practically the same:
  92
  93      RCL_renderComplex(camera,heightAt,0,0,constraints); */
  94   RCL_renderSimple(camera,heightAt,0,0,constraints);
  95
  96   puts(screen); // print out the rendered frame
  97
  98   return 0;     // done!
  99 }