src/starfield.cpp

   1 //
   2 // C++ Implementation: Starfield
   3 //
   4 // Description:
   5 //
   6 //
   7 // Author: Öyvind Johannessen <gathers@gmail.com>, (C) 2008
   8 //
   9 // Copyright: See COPYING file that comes with this distribution
  10 //
  11 //
  12 #include "starfield.h"
  13
  14 void Starfield::positionStar(int star)
  15 {
  16                 bool done=false;
  17                 int newx, newy;
  18                 while(!done){
  19                         newx=int(640.0*randy());
  20                         newy=int(215.0*randy());
  21                         done=true;
  22                         for(int n=0;n<nr_of_stars;n++){
  23                                 if(starx[n]==newx && stary[n]==newy){
  24                                         done=false;
  25                                         break;
  26                                 }
  27                         }
  28                 }
  29                 starx[star]=newx;
  30                 stary[star]=newy;
  31                 starc[star]=0;
  32                 starRed[star]=0.7+randy()*0.3;
  33                 starGreen[star]=0.7+randy()*0.3;
  34                 starBlue[star]=1;
  35 }
  36
  37
  38 Starfield::Starfield()
  39 {
  40                 for(int n=0;n<nr_of_stars;n++){
  41                         positionStar(n);
  42                 }
  43 }
  44
  45
  46 void Starfield::updateStars()
  47 {
  48         for(int n=0;n<nr_of_stars;n++){
  49                 starc[n]=starc[n]+float(4.0*randy()-4.1*randy());
  50                 if(int(starc[n])>=256)
  51                         starc[n]=255;
  52                 if(int(starc[n])<=0){
  53                         positionStar(n);
  54                 }
  55         }
  56 }
  57
  58
  59 void Starfield::drawStarsOn(SDL_Surface *surf)
  60 {
  61 //      Uint32 pixel;
  62                 if(SDL_LockSurface(surf)){
  63                         fprintf(stderr,"Couldn't lock surface to draw stars..\n");
  64                         return;
  65                 }
  66                 for(int n=0;n<nr_of_stars;n++){
  67                         putpixel(surf,starx[n],stary[n],(0xFF<<24)|(int(starc[n]*starRed[n])<<16)|(int(starc[n]*starGreen[n])<<8)|int(starc[n]*starBlue[n]));
  68 /*                      pixel=(0xFF<<24)|(int(50)<<16)|(int(140)<<8)|int(200);
  69                         putpixel(surf,starx[n],stary[n],pixel);*/
  70                 }
  71                 SDL_UnlockSurface(surf);
  72 }
  73