a Mandelbrot set plugin from Matthias

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@4504 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 195 insertions, 0 deletions

diff --git a/apps/plugins/mandelbrot.c b/apps/plugins/mandelbrot.c
new file mode 100644
index 0000000000..3585af80f9
--- /dev/null
+++ b/apps/plugins/mandelbrot.c
@@ -0,0 +1,195 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2004 Matthias Wientapper
+ *
+ * Thanks to Jens Arnold and Joerg Hohensohn for the speed tips.
+ * Boy, that was a hell of a code review ;-)
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ *
+ * further optimization ideas:
+ *    - incremental recalculation when moving
+ *    
+ ****************************************************************************/
+#include "plugin.h"
+
+#ifdef HAVE_LCD_BITMAP // this is not fun on the player
+
+static struct plugin_api* rb;
+static char buff[32];
+static int lcd_aspect_ratio;
+static int x_min;
+static int x_max;
+static int y_min;
+static int y_max;
+static int delta;
+static int max_iter;
+
+void init_mandelbrot_set(void){
+    x_min = -5<<27;  // -2.5<<28
+    x_max =  1<<28;  //  1.0<<28
+    y_min = -1<<28;  // -1.0<<28
+    y_max =  1<<28;  //  1.0<<28
+    delta = (x_max - x_min) >> 3;  // /8
+    max_iter = 25;
+}
+
+void calc_mandelbrot_set(void){
+    
+    unsigned int start_tick;
+    int n_iter;
+    int x_pixel, y_pixel;
+    int x, x2, y, y2, a, b;
+    int x_fact, y_fact;
+    
+    start_tick = *rb->current_tick;  
+    
+    rb->lcd_clear_display();
+    rb->lcd_update();
+
+    x_fact = (x_max - x_min) / LCD_WIDTH;
+    y_fact = (y_max - y_min) / LCD_HEIGHT;
+    
+    for(y_pixel = LCD_HEIGHT-1; y_pixel>=0; y_pixel--){    
+        b = (y_pixel * y_fact) + y_min;
+        for (x_pixel = LCD_WIDTH-1; x_pixel>=0; x_pixel--){
+            a = (x_pixel * x_fact) + x_min;
+            x = 0;
+            y = 0;
+            n_iter = 0;
+            
+            while (++n_iter<=max_iter) {
+                x >>= 14;
+                y >>= 14;
+                x2 = x * x;
+                y2 = y * y;
+                
+                if (x2 + y2 > (4<<28)) break;
+                
+                y = 2 * x * y + b;
+                x = x2 - y2 + a;
+            }
+            
+            // "coloring"
+            if ( (n_iter > max_iter) ||
+                (n_iter == (max_iter >> 1)) ||
+                (n_iter == (max_iter >> 2)) ||
+                (n_iter == (max_iter >> 3)) 
+                ){
+                rb->lcd_drawpixel(x_pixel,y_pixel);
+            }
+        }
+        
+        /* update block of 8 lines */
+        if ((y_pixel & 0x7) == 0)
+            rb->lcd_update_rect(0, y_pixel, LCD_WIDTH, 8);
+    }
+    
+    /* we want to know how long we had to wait */
+    rb->lcd_setfont(FONT_SYSFIXED);
+    rb->snprintf(buff, sizeof(buff), "%d", (*rb->current_tick - start_tick));
+    rb->lcd_puts(0,0,buff);
+    rb->snprintf(buff, sizeof(buff), "%d",  max_iter);
+    rb->lcd_puts(0,1,buff);
+    rb->lcd_update_rect(0,0,24,16);
+}
+
+enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
+{
+
+    TEST_PLUGIN_API(api);
+    (void)parameter;
+    rb = api;
+
+    init_mandelbrot_set();
+    lcd_aspect_ratio = ((LCD_WIDTH<<14) / LCD_HEIGHT)<<14;
+
+    /* main loop */
+    while (true){
+
+	    calc_mandelbrot_set();
+
+	    /* FIXME: is this the right way to empty the key-queue? 
+	       (Otherwise we have to process things twice :-/ ?! */
+	    
+	    rb->button_get(true);
+
+
+	    switch (rb->button_get(true)) {
+	    case BUTTON_OFF:
+	        return PLUGIN_OK;
+
+	    case BUTTON_ON:
+	        x_min -= ((delta>>14)*(lcd_aspect_ratio>>14));
+	        x_max += ((delta>>14)*(lcd_aspect_ratio>>14));
+	        y_min -= delta;
+	        y_max += delta;
+	        delta = (x_max - x_min) >> 3;
+	        break;
+ 	        
+
+	    case BUTTON_PLAY:
+	        x_min += ((delta>>14)*(lcd_aspect_ratio>>14));
+	        x_max -= ((delta>>14)*(lcd_aspect_ratio>>14));
+	        y_min += delta;
+	        y_max -= delta;
+	        delta = (x_max - x_min) >> 3;
+	        break;
+      
+	    case BUTTON_UP:
+	        y_min -= delta;
+	        y_max -= delta;
+	        break;
+
+	    case BUTTON_DOWN:
+	        y_min += delta;
+	        y_max += delta;
+	        break;
+
+	    case BUTTON_LEFT:
+	        x_min -= delta;
+	        x_max -= delta;
+	        break;
+
+	    case BUTTON_RIGHT:
+	        x_min += delta;
+	        x_max += delta;
+	        break;
+
+	    case BUTTON_F1:
+	        if (max_iter>5){
+		    max_iter -= 5;
+	        }
+	        break;
+
+	    case BUTTON_F2:
+	        if (max_iter < 195){
+		    max_iter += 5;
+	        }
+	        break;
+
+	    case BUTTON_F3:
+	        init_mandelbrot_set();
+	        break;
+
+	        
+	    case SYS_USB_CONNECTED:
+	        rb->usb_screen();
+	        return PLUGIN_USB_CONNECTED;
+	    }
+    }
+    return false;
+}
+#endif