2 files changed, 124 insertions, 0 deletions
diff --git a/demos/mandelbrot/main.c b/demos/mandelbrot/main.c
new file mode 100644
index 00000000..a726320e
--- /dev/null
+++ b/demos/mandelbrot/main.c
@@ -0,0 +1,18 @@
+#include "ch.h"
+#include "hal.h"
+#include "gdisp.h"
+
+int main(void) {
+	halInit();
+	chSysInit();
+
+	gdispInit();
+	gdispSetOrientation(GDISP_ROTATE_270);
+
+	mandelbrotInit(50, 50, 512);
+
+	while(TRUE) {
+	
+	}
+}
+
diff --git a/demos/mandelbrot/mandelbrot.c b/demos/mandelbrot/mandelbrot.c
new file mode 100644
index 00000000..ec4f68f5
--- /dev/null
+++ b/demos/mandelbrot/mandelbrot.c
@@ -0,0 +1,106 @@
+#include "ch.h"
+#include "hal.h"
+#include "gdisp.h"
+
+int count = 0;
+float mag = 1;
+float offsetx = -0.756423894274328;
+float offsety = 0.064179410646170;
+static float width, height;
+static uint16_t iterations, screen_off_x, screen_off_y;
+static uint16_t *FrameBuffer;
+
+static int generateColor(int count, int base) {
+	int r,g,b;
+	int d = (count % base) * 256 / base;
+	int m = (int)(d / 42.667);
+ 
+	switch(m) {
+		case 0: r=0; g=6*d; b=255; break;
+		case 1: r=0; g=255; b=255-6*(d-43); break;
+		case 2: r=6*(d-86); g=255; b=0; break;
+		case 3: r=255; g=255-6*(d-129); b=0; break;
+		case 4: r=255; g=0; b=6*(d-171); break;
+		case 5: r=255-6*(d-214); g=0; b=255; break;
+		default: r=0; g=0; b=0; break;
+	}
+ 
+	return (((r >> 3) & 0x1f) << 11) | (((g >> 2) & 0x3f) << 5) | ((b >> 3) & 0x1f);
+}
+ 
+static void complex_mult(float ar,float ai,float br,float bi, float *cr,float *ci) {
+	// C = A * B
+	*cr = ar * br - ai * bi;
+	*ci = ar * bi + ai * br;
+}
+ 
+static float complex_abs2(float r,float i) {
+	float ar,ai;
+	complex_mult(r,i,r,-i,&ar,&ai);
+
+	return ar;
+}
+
+void mandelbrotInit(uint16_t mandel_width, uint16_t mandel_height, uint16_t mandel_iterations) {
+	const char *msg = "ChibiOS/GFX";
+
+	width = (float)mandel_width;
+	height = (float)mandel_height;
+	iterations = mandel_iterations;
+
+	FrameBuffer = chHeapAlloc(NULL, width * height * sizeof(uint16_t));	
+	if(FrameBuffer == NULL)
+		return;
+
+	screen_off_x = (gdispGetWidth() - width) / 2;
+	screen_off_y = (gdispGetHeight() - height) / 2;
+
+	gdispClear(Black);
+	gdispDrawString((gdispGetWidth() - gdispGetStringWidth(msg, &fontUI2Double)) / 2, 5, "ChibiOS/GFX", &fontUI2Double, White);
+
+	while(TRUE) {
+		mandelbrotLoop();
+	}
+}
+
+void mandelbrotLoop() {
+	int x, y;
+    int pos = 0;
+ 
+	for(y = 0; y < height; y++) {
+		for(x = 0; x < width; x++) {
+			float cr = (x - width/2.) / (width/2.) / mag + offsetx;
+			float ci = (y - width/2.) / (width/2.) / mag + offsety;
+			float zr = 0;
+			float zi = 0;
+			int t;
+
+			for(t = 0; t < iterations; t++) {
+				if(complex_abs2(zr,zi) > 4) 
+					break;
+				complex_mult(zr,zi,zr,zi,&zr,&zi);
+				zr += cr;
+				zi += ci;
+			}
+
+			FrameBuffer[pos++] = generateColor(t, 64);
+		}
+	}
+ 
+	gdispBlitArea(screen_off_x, screen_off_y, width, height, FrameBuffer);
+
+	// magnification
+	mag = mag * 1.2;
+
+	// panning 
+	//offsety += 0.001;
+	//offsetx += 0.0016;
+ 
+	if(count++ > 500)  {
+		offsetx = -0.756423894274328;
+		offsety = 0.064179410646170;
+		mag = 1;
+		count = 0;
+	}
+}
+