mandelfp.noc

//==============================================================================
// code below by Martin Wendt, all else part of gd32vf103inator
// except for minor additions to display.c/.h -> dp_imagefill565()
#include "mandelfp.h"
#include "snip1.h"
#include "myasm.h"
#define FIXSIZE 14
#define mul(a,b) ((((int)a)*(b))>>FIXSIZE)
#define fixpt(a) ((int)(((a)*(1<<FIXSIZE))))
#define SCREEN_WIDTH   160
#define SCREEN_HEIGHT  80
__attribute__((noinline))
void mandelfp()
{
//float xmin,ymin,xmax,ymax,xs,ys;
int x0,y0,p,q,xn;
int i,x,y,z;
const int maxiter = 300;
int xs,ys;
//all of this below could already
//perform in fixpt space!
int xmin=-20666;//-1.26136183;
int xmax=-20441;//-1.24763480;
int ymin= 6168;//0.37648215;
int ymax= 6337;//0.38676353;
int s=-1;

struct linebuf linebuf;

while (1)
{
    s=s*-1;
for (z=0;z<200;z++)
{ 
    xmin-=z*s;
    xmax+=z*s;
    ymin-=z*s;
    ymax+=z*s;
    int xs=(xmax-xmin)*16/SCREEN_WIDTH;
    int ys=(ymax-ymin)*16/SCREEN_HEIGHT;
   
    for (y=0;y<SCREEN_HEIGHT;y++) {
      q= ymin+(y*ys)/16;
      for (x=0;x<SCREEN_WIDTH;x++) {                        
        p = xmin+(x*xs)/16;
        
            xn=0;
            x0=0;
            y0=0;
            i=0;
            while ((mul(xn,xn)+mul(y0,y0))<(65536) && ++i<maxiter)  
            {
                xn=mul((x0+y0),(x0-y0)) +p; 
                //xn=mul(myasm(x0,y0),(x0-y0)) +p;           
                //xn=myasm(x0,y0,p);
                //xn+=+p;
                y0=mul(32768,mul(x0,y0)) +q;
                x0=xn;
                
            }
            if (i==maxiter) i=1;
            {
                //linebuf.buf[y*160+x]=i*111;
                linebuf.buf[y*160*2+x*2]=i;
                linebuf.buf[y*160*2+x*2+1]=i*2;
            }  
        }
      }
    dp_imagefill565(linebuf.buf);
}
} 
}