zooming mandelbrot proof-of-concept

lcd/display.c

@@ -157,14 +157,22 @@ void lcdFill(char f){
 void lcdSetPixel(char x, char y, bool f){
 	char y_byte = (RESY-(y+1)) / 8;
 	char y_off = (RESY-(y+1)) % 8;
-	char byte = lcdBuffer[y_byte*RESX+(RESX-x)%RESX];
+	char byte = lcdBuffer[y_byte*RESX+(RESX-(x+1))];
 	if (f) {
 		byte |= (1 << y_off);
 	} else {
 		byte &= ~(1 << y_off);
 	}
-	lcdBuffer[y_byte*RESX+(RESX-x)%RESX] = byte;
+	lcdBuffer[y_byte*RESX+(RESX-(x+1))] = byte;
 }
+
+bool lcdGetPixel(char x, char y){
+	char y_byte = (RESY-(y+1)) / 8;
+	char y_off = (RESY-(y+1)) % 8;
+	char byte = lcdBuffer[y_byte*RESX+(RESX-(x+1))];
+	return byte & (1 << y_off);
+}
+
 void lcdDisplay(uint32_t shift)
 {
     lcdWrite(0,0xB0);

lcd/display.h

@@ -24,5 +24,6 @@ void lcdFill(char f);
 void lcdDisplay(uint32_t shift);
 void lcdInvert(void);
 void lcdSetPixel(char x, char y, bool f);
+bool lcdGetPixel(char x, char y);
 
 #endif

modules/mandelbrot.c

@@ -0,0 +1,171 @@
+#include <sysinit.h>
+
+#include "basic/basic.h"
+
+#include "lcd/render.h"
+#include "lcd/display.h"
+#include "lcd/allfonts.h"
+
+#define FIXSIZE 25
+#define mul(a,b) ((((long long)a)*(b))>>FIXSIZE)
+#define fixpt(a) ((long)(((a)*(1<<FIXSIZE))))
+#define integer(a) (((a)+(1<<(FIXSIZE-1)))>>FIXSIZE)
+
+void ReinvokeISP(void);
+void EnableWatchdog(uint32_t ms);
+void delayms(uint32_t ms);
+
+/**************************************************************************/
+void checkISP(void) {
+    if(gpioGetValue(RB_BTN0)==0){
+        gpioSetValue (RB_LED1, CFG_LED_ON); 
+        delayms(200);
+        gpioSetValue (RB_LED1, CFG_LED_OFF); 
+        while(gpioGetValue(RB_BTN0)==0);
+        EnableWatchdog(1000*5);
+        ReinvokeISP();
+    }
+}
+
+void cross(char x, char y) {
+    lcdSetPixel(x,y,false);
+    lcdSetPixel(x+1,y,true);
+    lcdSetPixel(x-1,y,true);
+    lcdSetPixel(x,y+1,true);
+    lcdSetPixel(x,y-1,true);
+    lcdSetPixel(x+2,y,false);
+    lcdSetPixel(x-2,y,false);
+    lcdSetPixel(x,y+2,false);
+    lcdSetPixel(x,y-2,false);
+    lcdDisplay(0);
+}
+
+void module_mandelbrot(void) {
+    gpioSetValue (RB_LED1, CFG_LED_OFF); 
+    backlightInit();
+    
+    bool toggle = false;
+    int counter = 0;
+    
+    long r0,i0,p,q,rn,tot;
+    //double xmin=-2.5,ymin=-1.5,xmax=1.5,ymax=1.5,xs,ys;
+    
+    double rmin0=-2.2*0.9, imin0=-2.0*0.9, rmax0=1.0*0.9, imax0=2.0*0.9;
+    double i_center=0, r_center=0;
+    double rmin=rmin0,imin=imin0,rmax=rmax0,imax=imax0,rs,is;
+    int iteration,r,i;
+    double zoom = 1;
+    int iteration_max = 300;
+    int x_center = 45;
+    int y_center= 40;
+    while (1) {
+        checkISP();
+        lcdDisplay(0);
+        delayms(100);
+        
+        rs=(rmax-rmin)/68.0; 
+        is=(imax-imin)/96.0; 
+        
+        
+        for (r=0;r<RESY;r++) {
+            for (i=0;i<RESX;i++) {
+                p=fixpt(rmin+r*rs);
+                q=fixpt(imin+i*is);
+                rn=0;
+                r0=0;
+                i0=0;
+                iteration=0;
+                while ((mul(rn,rn)+mul(i0,i0))<fixpt(4) && ++iteration<iteration_max)  {
+                    rn=mul((r0+i0),(r0-i0)) +p;           
+                    i0=mul(fixpt(2),mul(r0,i0)) +q;
+                    r0=rn;
+                }
+                tot+=iteration;
+                if (iteration==iteration_max) iteration=1;
+                bool pixel = ( iteration>1);
+                
+                lcdSetPixel (i,r,pixel);
+                //lcdSetPixel ((RESX-1)-i,r,pixel); 
+                checkISP();
+            }
+        }
+        lcdDisplay(0);
+        
+        //for (int x=0; x<RESX;x++){
+        //    for(int y=0; y<RESY;y++){
+        //        bool p = lcdGetPixel(x,y);
+        //        lcdSetPixel(x,y,~p);
+        //        lcdDisplay(0);
+        //   }
+        //}
+        
+        
+        bool selected_val = lcdGetPixel(x_center, y_center);
+        for (int delta = 0; delta<100; delta++){
+            double test_i = imin + (imax-imin)*x_center/96.0;
+            double test_r = rmin +(imax-rmin)*y_center/68.0;
+            //double dist = test_i * test_i + test_r * test_r;
+            //double dist = ((i_center - test_i)*(i_center - test_i) + (r_center - test_r)*(r_center - test_r))*1.0/zoom;
+            double dist = 0;
+            if (x_center + delta < RESX && lcdGetPixel(x_center+delta,y_center) != selected_val && dist <=2){
+                x_center +=delta-1;
+                
+                break;
+            }
+            if (x_center - delta >= 0 && lcdGetPixel(x_center-delta,y_center) != selected_val && dist <=2){
+                x_center -=delta+1;
+                break;
+            }
+            if (y_center + delta < RESY && lcdGetPixel(x_center, y_center+delta) != selected_val && dist <=2){
+                y_center +=delta-1;
+                break;
+            }
+            if (y_center -delta >= 0 && lcdGetPixel(x_center, y_center-delta) != selected_val && dist <=2) {
+                y_center -= delta+1;
+                break;
+            }
+        }
+        
+       cross(x_center, y_center);
+        
+        i_center = x_center/96.0 -0.5;
+        r_center = y_center/68.0 -0.5;
+        
+        double i_off = (imax-imin)*i_center;
+        double r_off = (rmax-rmin)*r_center;
+
+        imin += i_off*1.0;
+        imax += i_off*1.0;
+        rmin += r_off*1.0;
+        rmax += r_off*1.0;
+        
+        imin = imin + (imax-imin)*(1-zoom);
+        imax = imax - (imax-imin)*(1-zoom);
+        rmin = rmin +(rmax-rmin)*(1-zoom);
+        rmax = rmax -(rmax-rmin)*(1-zoom);
+        //imin*=zoom;
+        //imax*=zoom;
+        //rmin*=zoom;
+        //rmax*=zoom;
+        
+        zoom *= 0.995;
+        iteration_max = iteration_max*1.02;
+        
+        x_center = RESX/2;
+        y_center= RESY/2;
+        
+        cross(x_center,y_center);
+        if (counter > 24) {
+            if (toggle) {
+                toggle = false;
+            } else {
+                toggle = true;
+            }
+            counter = 0;
+        } else {
+            counter ++;
+        }
+        
+    }
+    return;
+}