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