forked from len0rd/rockbox
422 lines
11 KiB
C
422 lines
11 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2004 Matthias Wientapper
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* Heavily extended 2005 Jens Arnold
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "fractal_sets.h"
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#include "mandelbrot_set.h"
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#define BUTTON_YIELD_TIMEOUT (HZ / 4)
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#ifdef USEGSLIB
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static unsigned char imgbuffer[LCD_HEIGHT];
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#else
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static fb_data imgbuffer[LCD_HEIGHT];
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#endif
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#ifdef USEGSLIB
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#define LCOLOR(iter) ((iter ^ 7) << 5)
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#else
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/*
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* Spread iter's colors over color range.
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* 345 (=15*26-45) is max_iter maximal value
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* This implementation ignores pixel format, thus it is not uniformly spread
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*/
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#if LCD_DEPTH > 24
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/* when LCD_DEPTH is 32 casting to 64bit intermediate is needed to prevent
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* overflow and warning 'left shift count >= width of type'
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*/
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#define LCOLOR(iter) ((unsigned int)(((unsigned long long)iter << LCD_DEPTH) / 345))
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#else
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#define LCOLOR(iter) ((iter << LCD_DEPTH) / 345)
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#endif
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#endif
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#ifdef HAVE_LCD_COLOR
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#define COLOR(iter) FB_SCALARPACK(LCOLOR(iter))
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#define CONVERGENCE_COLOR FB_RGBPACK(0, 0, 0)
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#else /* greyscale */
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#define COLOR(iter) (unsigned char)LCOLOR(iter)
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#define CONVERGENCE_COLOR 0
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#endif
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#if CONFIG_LCD == LCD_SSD1815
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/* Recorder, Ondio: pixel_height == 1.25 * pixel_width */
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#define MB_HEIGHT (LCD_HEIGHT*5/4)
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#else
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/* square pixels */
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#define MB_HEIGHT LCD_HEIGHT
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#endif
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#define MB_XOFS (-0x03000000L) /* -0.75 (s5.26) */
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#if (3000 * MB_HEIGHT / LCD_WIDTH) >= 2400 /* width is limiting factor */
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#define MB_XFAC (0x06000000LL) /* 1.5 (s5.26) */
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#define MB_YFAC (MB_XFAC*MB_HEIGHT / LCD_WIDTH)
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#else /* height is limiting factor */
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#define MB_YFAC (0x04cccccdLL) /* 1.2 (s5.26) */
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#define MB_XFAC (MB_YFAC*LCD_WIDTH / MB_HEIGHT)
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#endif
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#ifndef USEGSLIB
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#define UPDATE_FREQ (HZ/50)
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#endif
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/* fixed point format s5.26: sign, 5 bits integer part, 26 bits fractional part */
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struct fractal_ops *ops;
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long x_min;
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long x_max;
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long x_step;
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long x_delta;
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long y_min;
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long y_max;
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long y_step;
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long y_delta;
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int step_log2;
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unsigned max_iter;
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static void mandelbrot_init(void);
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static int mandelbrot_calc_low_prec(struct fractal_rect *rect,
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int (*button_yield_cb)(void *), void *button_yield_ctx);
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static int mandelbrot_calc_high_prec(struct fractal_rect *rect,
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int (*button_yield_cb)(void *), void *button_yield_ctx);
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static void mandelbrot_move(int dx, int dy);
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static int mandelbrot_zoom(int factor);
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static int mandelbrot_precision(int d);
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struct fractal_ops mandelbrot_ops =
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{
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.init = mandelbrot_init,
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.calc = NULL,
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.move = mandelbrot_move,
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.zoom = mandelbrot_zoom,
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.precision = mandelbrot_precision,
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};
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#define LOG2_OUT_OF_BOUNDS -32767
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static int ilog2_fp(long value) /* calculate integer log2(value_fp_6.26) */
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{
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int i = 0;
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if (value <= 0)
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{
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return LOG2_OUT_OF_BOUNDS;
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}
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else if (value > (1L << 26))
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{
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while (value >= (2L << 26))
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{
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value >>= 1;
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i++;
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}
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}
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else
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{
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while (value < (1L << 26))
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{
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value <<= 1;
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i--;
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}
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}
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return i;
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}
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static int recalc_parameters(void)
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{
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x_step = (x_max - x_min) / LCD_WIDTH;
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y_step = (y_max - y_min) / LCD_HEIGHT;
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step_log2 = ilog2_fp(MIN(x_step, y_step));
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if (step_log2 == LOG2_OUT_OF_BOUNDS)
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return 1; /* out of bounds */
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x_delta = X_DELTA(x_step);
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y_delta = Y_DELTA(y_step);
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max_iter = MAX(15, -15 * step_log2 - 45);
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ops->calc = (step_log2 <= -10) ?
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mandelbrot_calc_high_prec : mandelbrot_calc_low_prec;
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return 0;
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}
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static void mandelbrot_init(void)
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{
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ops = &mandelbrot_ops;
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x_min = MB_XOFS - MB_XFAC;
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x_max = MB_XOFS + MB_XFAC;
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y_min = -MB_YFAC;
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y_max = MB_YFAC;
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recalc_parameters();
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}
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static int mandelbrot_calc_low_prec(struct fractal_rect *rect,
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int (*button_yield_cb)(void *), void *button_yield_ctx)
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{
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#ifndef USEGSLIB
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long next_update = *rb->current_tick;
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int last_px = rect->px_min;
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#endif
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unsigned n_iter;
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long a32, b32;
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short x, x2, y, y2, a, b;
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int p_x, p_y;
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unsigned long last_yield = *rb->current_tick;
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unsigned long last_button_yield = *rb->current_tick;
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a32 = x_min + x_step * rect->px_min;
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for (p_x = rect->px_min; p_x < rect->px_max; p_x++)
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{
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a = a32 >> 16;
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b32 = y_min + y_step * (LCD_HEIGHT - rect->py_max);
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for (p_y = rect->py_max - 1; p_y >= rect->py_min; p_y--)
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{
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b = b32 >> 16;
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x = a;
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y = b;
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n_iter = 0;
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while (++n_iter <= max_iter)
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{
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x2 = MULS16_ASR10(x, x);
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y2 = MULS16_ASR10(y, y);
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if (x2 + y2 > (4<<10)) break;
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y = 2 * MULS16_ASR10(x, y) + b;
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x = x2 - y2 + a;
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}
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if (n_iter > max_iter)
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imgbuffer[p_y] = CONVERGENCE_COLOR;
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else
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imgbuffer[p_y] = COLOR(n_iter);
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/* be nice to other threads:
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* if at least one tick has passed, yield */
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if (TIME_AFTER(*rb->current_tick, last_yield))
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{
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rb->yield();
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last_yield = *rb->current_tick;
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}
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if (TIME_AFTER(*rb->current_tick, last_button_yield))
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{
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if (button_yield_cb(button_yield_ctx))
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{
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#ifndef USEGSLIB
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/* update screen part that was changed since last yield */
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rb->lcd_update_rect(last_px, rect->py_min,
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p_x - last_px + 1, rect->py_max - rect->py_min);
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#endif
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rect->px_min = (p_x == 0) ? 0 : p_x - 1;
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return 1;
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}
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last_button_yield = *rb->current_tick + BUTTON_YIELD_TIMEOUT;
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}
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b32 += y_step;
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}
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#ifdef USEGSLIB
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grey_ub_gray_bitmap_part(imgbuffer, 0, rect->py_min, 1,
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p_x, rect->py_min, 1, rect->py_max - rect->py_min);
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#else
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rb->lcd_bitmap_part(imgbuffer, 0, rect->py_min, 1,
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p_x, rect->py_min, 1, rect->py_max - rect->py_min);
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if ((p_x == rect->px_max - 1) ||
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TIME_AFTER(*rb->current_tick, next_update))
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{
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next_update = *rb->current_tick + UPDATE_FREQ;
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/* update screen part that was changed since last yield */
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rb->lcd_update_rect(last_px, rect->py_min,
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p_x - last_px + 1, rect->py_max - rect->py_min);
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last_px = p_x;
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}
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#endif
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a32 += x_step;
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}
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rect->valid = 0;
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return 0;
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}
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static int mandelbrot_calc_high_prec(struct fractal_rect *rect,
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int (*button_yield_cb)(void *), void *button_yield_ctx)
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{
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#ifndef USEGSLIB
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long next_update = *rb->current_tick;
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int last_px = rect->px_min;
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#endif
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unsigned n_iter;
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long x, x2, y, y2, a, b;
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int p_x, p_y;
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unsigned long last_yield = *rb->current_tick;
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unsigned long last_button_yield = *rb->current_tick;
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MULS32_INIT();
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a = x_min + x_step * rect->px_min;
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for (p_x = rect->px_min; p_x < rect->px_max; p_x++)
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{
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b = y_min + y_step * (LCD_HEIGHT - rect->py_max);
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for (p_y = rect->py_max - 1; p_y >= rect->py_min; p_y--)
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{
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x = a;
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y = b;
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n_iter = 0;
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while (++n_iter <= max_iter)
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{
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x2 = MULS32_ASR26(x, x);
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y2 = MULS32_ASR26(y, y);
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if (x2 + y2 > (4L<<26)) break;
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y = 2 * MULS32_ASR26(x, y) + b;
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x = x2 - y2 + a;
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}
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if (n_iter > max_iter)
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imgbuffer[p_y] = CONVERGENCE_COLOR;
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else
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imgbuffer[p_y] = COLOR(n_iter);
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/* be nice to other threads:
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* if at least one tick has passed, yield */
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if (TIME_AFTER(*rb->current_tick, last_yield))
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{
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rb->yield();
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last_yield = *rb->current_tick;
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}
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if (TIME_AFTER(*rb->current_tick, last_button_yield))
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{
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if (button_yield_cb(button_yield_ctx))
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{
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#ifndef USEGSLIB
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/* update screen part that was changed since last yield */
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rb->lcd_update_rect(last_px, rect->py_min,
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p_x - last_px + 1, rect->py_max - rect->py_min);
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#endif
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rect->px_min = (p_x == 0) ? 0 : p_x - 1;
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return 1;
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}
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last_button_yield = *rb->current_tick + BUTTON_YIELD_TIMEOUT;
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}
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b += y_step;
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}
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#ifdef USEGSLIB
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grey_ub_gray_bitmap_part(imgbuffer, 0, rect->py_min, 1,
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p_x, rect->py_min, 1, rect->py_max - rect->py_min);
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#else
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rb->lcd_bitmap_part(imgbuffer, 0, rect->py_min, 1,
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p_x, rect->py_min, 1, rect->py_max - rect->py_min);
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if ((p_x == rect->px_max - 1) ||
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TIME_AFTER(*rb->current_tick, next_update))
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{
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next_update = *rb->current_tick + UPDATE_FREQ;
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/* update screen part that was changed since last yield */
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rb->lcd_update_rect(last_px, rect->py_min,
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p_x - last_px + 1, rect->py_max - rect->py_min);
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last_px = p_x;
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}
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#endif
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a += x_step;
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}
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rect->valid = 0;
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return 0;
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}
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static void mandelbrot_move(int x_factor, int y_factor)
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{
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long dx = (long)x_factor * x_delta;
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long dy = (long)y_factor * y_delta;
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x_min += dx;
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x_max += dx;
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y_min += dy;
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y_max += dy;
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}
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static int mandelbrot_zoom(int factor)
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{
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int res;
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long factor_x = (long)factor * x_delta;
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long factor_y = (long)factor * y_delta;
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x_min += factor_x;
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x_max -= factor_x;
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y_min += factor_y;
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y_max -= factor_y;
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res = recalc_parameters();
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if (res) /* zoom not possible, revert */
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{
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mandelbrot_zoom(-factor);
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}
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return res;
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}
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static int mandelbrot_precision(int d)
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{
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int changed = 0;
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/* Increase precision */
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for (; d > 0; d--)
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{
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max_iter += max_iter / 2;
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changed = 1;
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}
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/* Decrease precision */
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for (; d < 0 && max_iter >= 15; d++)
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{
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max_iter -= max_iter / 3;
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changed = 1;
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}
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return changed;
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}
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