Fractal fern generator [2]

fern2.c

//
//  Martin Klingensmith
//  Fractal Fern generator.
//  2012
//  
//
#include <stdio.h>
#include <math.h>

#define WIDTH 1200
#define HEIGHT 1200

typedef __int32 int32_t;
typedef unsigned __int32 uint32_t;
typedef unsigned __int16 uint16_t;

void line(int x1, int y1, int x2, int y2);      // Draw line
void plot(int x, int y, uint32_t color);        // Plot pixel
void fern(int points);

//
//  BMP Magic value
//
struct {
  unsigned char magic[2];
} bmpmagic;
 
//
//  BMP header
//
struct {
  uint32_t filesz;
  uint16_t creator1;
  uint16_t creator2;
  uint32_t bmp_offset;
} bmpheader;

//
//  DIB header
//
struct {
  uint32_t header_sz;
  int32_t width;
  int32_t height;
  uint16_t nplanes;
  uint16_t bitspp;
  uint32_t compress_type;
  uint32_t bmp_bytesz;
  int32_t hres;
  int32_t vres;
  uint32_t ncolors;
  uint32_t nimpcolors;
} dib;

//
//  Pixel
//
typedef struct px {
    char b;
    char g;
    char r;
} px;

px pixels[WIDTH+1][HEIGHT];
uint32_t color;

int main()
{
    int x=0;
    uint16_t rowsize;
    //
    //  Start BMP
    //
    FILE *outfile = fopen("fern.bmp","w");
    if (outfile == NULL){
        fprintf(stderr,"Can't open file\n");
    }
    
    bmpmagic.magic[0] = 0x42;
    bmpmagic.magic[1] = 0x4D;
    bmpheader.creator1 = 0;
    bmpheader.creator2 = 0;
    bmpheader.bmp_offset = sizeof(bmpmagic) + sizeof(bmpheader) + sizeof(dib);
    dib.header_sz = sizeof(dib);
    dib.width = WIDTH;
    dib.height = HEIGHT;
    dib.nplanes = 1;
    dib.bitspp = 24;
    dib.compress_type = 0;
    
    rowsize = dib.bitspp * WIDTH * 4 / 32;  // row size, bytes
    rowsize += rowsize%4;                   // make multiple of 4 bytes
    
    dib.bmp_bytesz = rowsize * HEIGHT;
    dib.hres = 2835;
    dib.vres = 2835;
    dib.ncolors = 0;
    dib.nimpcolors = 0;
    bmpheader.filesz = dib.bmp_bytesz + 54;
    

    //
    //  Write BMP header
    //
    fwrite(&bmpmagic,1,sizeof(bmpmagic),outfile);
    fwrite(&bmpheader,1,sizeof(bmpheader),outfile);
    fwrite(&dib,1,sizeof(dib),outfile);

    //
    //  Initialize pixel buffer
    //
    memset(&pixels,0xFF,sizeof(pixels));

    //
    //  Fern
    //
    srand(time(NULL));
    fern(500000);
    
    //
    //  Write pixels to BMP
    //
    for(x=0;x<HEIGHT;x++)
    {
        fwrite(&(pixels[x]),1,3*WIDTH+3*WIDTH%4,outfile);
    }
    
    fclose(outfile);
    
	return 0;
}

//
//  Draw fern
//
void fern(int points)
{
    double x,y;
    double xn,yn;
    unsigned int px,py;
    int p;
    
    for(;points>0;points--){
        p = rand()%100;
        if(p < 2){
            color = 0x10FF50;        
			xn = 0;
			yn = .16*y;
			x = xn;
			y = yn;
        } else if (p < 8) {
            color = 0x10BB00;        
			xn = .2*x-.26*y;
			yn = .2*x+.23*y+1.65;
			x = xn;
			y = yn;
        } else if (p < 15) {
            color = 0x10FF10;
			xn = -.15*x+.28*y;
			yn = .26*x+.24*y+.44;
			x = xn;
			y = yn;
        } else {
            color = 0x10FF00;
			xn = .85*x+.04*y;
			yn = -.04*x+.98*y+1.6;
			x = xn;
			y = yn;
        };
        
        px = (unsigned int)(x*WIDTH/10+WIDTH/2);
        py = (unsigned int)(y*HEIGHT/10+HEIGHT/8);
        plot(px,py,color);
        plot(px+1,py-1,color*0x808080);
        plot(px,py-1,color*0xA0A0A0);
        plot(px+1,py,color*0x60A0A0);
        
        plot(px-1,py+1,color*0x808080);
        plot(px,py+1,color*0xA0A0A0);
        plot(px-1,py,color*0x101010);
        //printf("\n(%d,%d)",px,py);
    }

}

//
//  Pixel poke
//
void plot(int x, int y, uint32_t col)
{
    if(x>HEIGHT) return;
    if(y>WIDTH) return;
    pixels[y][x].r = (col >> 16) & 0xFF;
    pixels[y][x].g = (col >> 8) & 0xFF;
    pixels[y][x].b = col & 0xFF;
    return;
}