16 bits

Simple sample to show you how to write a pixel, and how to do double buffering.

Using library

GP2X minimal library by rlyeh, 2005

License

• Free for non-commercial projects (it would be nice receiving a mail from you).  Other cases, ask me first.
• GamePark Holdings is not allowed to use this library and/or use parts from it.

Source code

#include "minimal.h"

int main(int argc, char *argv[])
{
 gp2x_init(1000, 15, 11025,16,1,60, 1);

 while(1)
 {
  unsigned long  pad=gp2x_joystick_read();
  unsigned short color;

  if(pad & GP2X_VOL_DOWN) if(pad & GP2X_START) exit(0);

  if(pad & GP2X_A) color=gp2x_video_RGB_color15(255,0,0,0); //red
          else color=gp2x_video_RGB_color15(255,255,255,0); //white

  gp2x_video_RGB[0].screen16[160+120*320]=color;

  gp2x_video_RGB_flip(0);
 }
}

void gp2x_sound_frame(void *blah, void *buff, int samples) { }

Explanation

• Our gp2x_init line inits the whole library.  We set 1000 ticks per second, 15 bits video mode, 11025/16bits/stereo/60Hz sound mode, and solid font.
• Our gp2x_joystick_read line reads the joystick.  It is used to act properly to different button combinations.
• Our gp2x_video_RGB_color15 line sets color variable to a determinated color.
• Our gp2x_video_RGB [0].screen16 line updates the pixel at the middle of screen (160,120) with our color.
• Our gp2x_video_RGB_flip line updates the screen and our gp2x_video_RGB [0].screen16 pointer for next frame.
• Our gp2x_sound_frame line fills our sound buffer.  Note that this function will not generate any sound since we have written a void function.

C Compilation

arm-linux-gcc minimal.c 15bits.c -static -lpthread -lm

C++ Compilation

arm-linux-g++ minimal.c 15bits.c -static -lpthread -lm

Output

• this program puts a pixel at center of screen and does double buffering (pressing A changes the color).
• press volume down and start buttons to exit.