rockbox/apps/plugins/plasma.c
Jens Arnold 74e4b250a6 New plugin: Plasma effect, developed by Mat Holton, imtegerised and extended by Kevin Ferrare.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7590 a1c6a512-1295-4272-9138-f99709370657
2005-10-07 20:35:27 +00:00

263 lines
7 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Plasma demo plugin
*
* My crack at making a 80's style retro plasma effect for the fantastic
* rockbox!
* Okay, I could've hard-coded the sine wave values, I just wanted the
* challange of calculating them! silly: maybe, fun: yes!
*
* 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.
*
****************************************************************************/
#ifndef SIMULATOR /* not for simulator by now */
#include "plugin.h"
#ifdef HAVE_LCD_BITMAP /* and also not for the Player */
#include "gray.h"
/******************************* Globals ***********************************/
static struct plugin_api* rb; /* global api struct pointer */
static unsigned char *gbuf;
static unsigned int gbuf_size = 0;
static unsigned char wave_array[256]; /* Pre calculated wave array */
static unsigned char colours[256]; /* Smooth transition of shades */
static unsigned char graybuffer[LCD_HEIGHT*LCD_WIDTH]; /* off screen buffer */
static unsigned char sp1, sp2, sp3, sp4; /* Speed of plasma */
static int plasma_frequency;
/* Key assignement, all bitmapped models */
#define PLASMA_QUIT BUTTON_OFF
#define PLASMA_INCREASE_FREQUENCY BUTTON_UP
#define PLASMA_DECREASE_FREQUENCY BUTTON_DOWN
#define WAV_AMP 90
/* Precalculated sine * 16384 (fixed point 18.14) */
static const short sin_table[91] =
{
0, 285, 571, 857, 1142, 1427, 1712, 1996, 2280, 2563,
2845, 3126, 3406, 3685, 3963, 4240, 4516, 4790, 5062, 5334,
5603, 5871, 6137, 6401, 6663, 6924, 7182, 7438, 7691, 7943,
8191, 8438, 8682, 8923, 9161, 9397, 9630, 9860, 10086, 10310,
10531, 10748, 10963, 11173, 11381, 11585, 11785, 11982, 12175, 12365,
12550, 12732, 12910, 13084, 13254, 13420, 13582, 13740, 13894, 14043,
14188, 14329, 14466, 14598, 14725, 14848, 14967, 15081, 15190, 15295,
15395, 15491, 15582, 15668, 15749, 15825, 15897, 15964, 16025, 16082,
16135, 16182, 16224, 16261, 16294, 16321, 16344, 16361, 16374, 16381,
16384
};
static short sin(int val)
{
/* value should be between 0 and 360 degree for correct lookup*/
val%=360;
if(val<0)
val+=360;
/* Speed improvement through successive lookup */
if (val < 181)
{
if (val < 91)
{
/* phase 0-90 degree */
return (short)sin_table[val];
}
else
{
/* phase 91-180 degree */
return (short)sin_table[180-val];
}
}
else
{
if (val < 271)
{
/* phase 181-270 degree */
return -(short)sin_table[val-180];
}
else
{
/* phase 270-359 degree */
return -(short)sin_table[360-val];
}
}
return 0;
}
/*
* Main wave function so we don't have to re-calc the sine
* curve every time. Mess around WAV_AMP and FREQ to make slighlty
* weirder looking plasmas!
*/
static void wave_table_generate(void)
{
int i;
for (i=0;i<256;++i)
{
wave_array[i] = (unsigned char)((WAV_AMP
* (sin((i * 360 * plasma_frequency) / 256))) / 16384);
}
}
/*
* This function is to make a smooth shade from white into
* black and back into white again. I thought this would be quicker
* than calculating on the fly - am I wrong?
*/
static void shades_generate(void)
{
int i=1;
int j=0;
int nAdd=2;
for(i=0; i < 256; ++i)
{
colours[i] = j;
j += nAdd;
if(j > 240 || j < 2)
{
nAdd = -nAdd;
}
}
}
void cleanup(void *parameter)
{
(void)parameter;
gray_release();
rb->backlight_set_timeout(rb->global_settings->backlight_timeout);
}
/*
* Main function that also contain the main plasma
* algorithm.
*/
int main(void)
{
plasma_frequency = 1;
int shades, button, x, y;
unsigned char p1,p2,p3,p4,t1,t2,t3,t4, z;
int n=0;
/*Generate the neccesary pre calced stuff*/
wave_table_generate();
shades_generate();
/* get the remainder of the plugin buffer */
gbuf = (unsigned char *) rb->plugin_get_buffer(&gbuf_size);
shades = gray_init(rb, gbuf, gbuf_size, false, LCD_WIDTH, LCD_HEIGHT/8,
32, NULL) + 1;
/* switch on grayscale overlay */
gray_show(true);
sp1 = 4;
sp2 = 2;
sp3 = 4;
sp4 = 2;
p1=p2=p3=p4=0;
while (true)
{
t1=p1;
t2=p2;
n=0;
for(y = 0; y < LCD_HEIGHT; ++y)
{
t3=p3;
t4=p4;
for(x = 0; x < LCD_WIDTH; ++x)
{
z = wave_array[t1] + wave_array[t2] + wave_array[t3]
+ wave_array[t4];
graybuffer[n] = colours[z];
t3+=1;
t4+=2;
++n;
}
t1+=2;
t2+=1;
rb->yield();
}
p1+=sp1;
p2-=sp2;
p3+=sp3;
p4-=sp4;
gray_ub_gray_bitmap(graybuffer, 0, 0, LCD_WIDTH, LCD_HEIGHT);
button = rb->button_get(false);
switch(button)
{
case(PLASMA_QUIT):
cleanup(NULL);
return PLUGIN_OK;
break;
case (PLASMA_INCREASE_FREQUENCY):
++plasma_frequency;
wave_table_generate();
break;
case (PLASMA_DECREASE_FREQUENCY):
if(plasma_frequency>1)
{
--plasma_frequency;
wave_table_generate();
}
break;
default:
if (rb->default_event_handler_ex(button, cleanup, NULL)
== SYS_USB_CONNECTED)
return PLUGIN_USB_CONNECTED;
break;
}
}
}
/*************************** Plugin entry point ****************************/
enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
{
int ret;
/*
* this macro should be called as the first thing you do in the plugin.
* it test that the api version and model the plugin was compiled for
* matches the machine it is running on
*/
TEST_PLUGIN_API(api);
rb = api; // copy to global api pointer
(void)parameter;
if (rb->global_settings->backlight_timeout > 0)
rb->backlight_set_timeout(1);/* keep the light on */
ret = main();
return ret;
}
#endif // #ifdef HAVE_LCD_BITMAP
#endif // #ifndef SIMULATOR