112 lines
3.2 KiB
C
112 lines
3.2 KiB
C
/* Derived from the 2011 IOCCC submission by peter.eastman@gmail.com
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* http://www.ioccc.org/2011/eastman/eastman.c
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* --
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* Public Domain -- but you're looking at this for ideas of techniques
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* and methods, not trying to cut&paste an entire application, anyway.
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* --
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* When you need to blit an entire screenfull of data to an LCD
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* display, the basic idea is to exploit the auto-increment feature of
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* the display controller when it writes to screen memory. You start
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* by resetting the 'cursor' to the 0,0 position, and then stream
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* width*height pixels out.
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* --
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* Chris Baird,, <cjb@brushtail.apana.org.au> April 2013
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*/
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#include <math.h>
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#include "ch.h"
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#include "hal.h"
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#include "gfx.h"
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#include "ssd2119.h"
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#define Lightgrey (HTML2COLOR(0xC0C0C0))
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#define Midgrey (HTML2COLOR(0x606060))
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#define Darkgrey (HTML2COLOR(0x303030))
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/* ---------------------------------------------------------------------- */
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/* As of early April 2013, the /gfx extension tries to keep the low-level
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* stuff away from our filthy paws. So Code Duplication.
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* (Possibly to be replaced with gdispStartStream(), gdispWriteStream()
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* and gdispStopStream() in the future.)
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*/
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#define GDISP_REG (*((volatile uint16_t *) 0x60000000)) /* DC = 0 */
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#define GDISP_RAM (*((volatile uint16_t *) 0x60100000)) /* DC = 1 */
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inline void write_index (uint16_t index) { GDISP_REG = index; }
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inline void write_data (uint16_t data) { GDISP_RAM = data; }
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#define write_reg(reg, data) { write_index(reg); write_data(data); }
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void reset_cursor (void)
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{
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write_reg (SSD2119_REG_X_RAM_ADDR, 0);
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write_reg (SSD2119_REG_Y_RAM_ADDR, 0);
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}
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#define StartStream() { write_index (SSD2119_REG_RAM_DATA); }
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#define WriteStream(x) { write_data (x); }
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#define StopStream() /* NOP */
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/* ---------------------------------------------------------------------- */
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void main (void)
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{
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uint16_t xx, yy, colour;
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halInit();
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chSysInit();
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gdispInit();
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uint16_t width = (uint16_t)gdispGetWidth();
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uint16_t height = (uint16_t)gdispGetHeight();
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float i=height/5+height%2+1, floorstart=height/5-1, spherespin=0.0,
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l=width/2, m=height/4, n=.01*width, o=0.0, rotspeed=0.1, h, f, g;
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while (TRUE)
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{
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reset_cursor ();
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StartStream ();
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for (xx=yy=0;
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h = (m-yy)/i, f=-.3*(g=(l-xx)/i)+.954*h, yy<height;
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yy += (xx = ++xx%width)==0 )
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{
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if (g*g < 1-h*h) /* if inside the ball */
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if (((int)(9-spherespin+(.954*g+.3*h)/sqrtf(1-f*f))+(int)(2+f*2))%2==0)
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colour = Red;
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else
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colour = White;
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else
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{
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if (xx<floorstart || xx>width-floorstart)
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colour = Darkgrey; /* side wall */
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else
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colour = Lightgrey; /* back wall */
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if (yy > height-floorstart)
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if (xx < height-yy || height-yy > width-xx) /* floor */
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colour = Darkgrey;
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else
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colour = Midgrey;
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if (g*(g+.6)+.09+h*h < 1)
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colour >>= 1; /* ball shadow; make it darker */
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}
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WriteStream (colour); /* pixel to the LCD */
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}
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StopStream();
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spherespin += rotspeed;
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m += o;
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o = m > height-1.75*floorstart ? -.04*height : o+.002*height;
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n = (l+=n)<i || l>width-i ? rotspeed=-rotspeed,-n : n;
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}
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}
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/* ---------------------------------------------------------------------- */
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