adam-buckley · October 23, 2017 10:56 · adam-buckley · Oct 23, 2017 · greenbreakfast · Oct 23, 2017
diff --git a/bouncing_dot.c b/bouncing_dot.c
 /**
 * A small demo of a dot bouncing inside a 128x64 OLED screen, using the Onion Omega 2. Note this isn't using the
 * OLED expansion, but a cheapo screen I bought from China, using the SSD1306 (as far as I could tell) driver.
 * This was only a personal exercise to see how easy it is to setup, it might be handly to someone else learning!
 *
 * To compile:
 *    - install gcc and make (See: https://docs.onion.io/omega2-docs/c-compiler-on-omega.html)
 *    - install git (Follow this: https://docs.onion.io/omega2-docs/installing-and-using-git.html)
 *    - install python-dev
 *    - git clone the i2c exp driver (https://github.com/OnionIoT/i2c-exp-driver)
 *    - (At the time of writing) Alter the makefile according to this bug report (https://github.com/OnionIoT/i2c-exp-driver/issues/18)
 *    - go into the "i2c-exp-driver" project and compile with `make`
 *    - copy bin, include, lib directories to /usr
 *    - compile gist below with `gcc bouncing_dot.c -loniondebug -lonioni2c -lonionoledexp`
 *    - Run!
 *
 * @author Adam Buckley <[email protected]>
 */
 // #include <stdio.h>
 #include <unistd.h>
 #include <oled-exp.h>

 int main() {

  // Init the OLED
  int status  = oledDriverInit();
  status |= oledSetDisplayPower(1);
  
  int x = 0, y = 0;
  int delta_x = 1, delta_y = 1;

  // Run forever
  while(1) {
    x += delta_x;
    y += delta_y;

    // When X hits a boundary on the OLED, flip the delta position
    if (x == 0 || x == 63) {
      delta_x *= -1;
    }

    // Do the same for the y coordinate
    if (y == 0 || y == 127) {
      delta_y *= -1;
    }
  
    // Set cursor to correct position
    // The way this works is that while the height of the OLED is 64px, there
    // is 8 logical rows, each with 8 addressable pixels. So the code below is just
    // working out where a pixel (e.g x = 57) should be placed
    
    // See https://docs.onion.io/omega2-docs/oled-expansion-c-library.html#understanding-the-display-1 for more info
    status |= oledSetCursorByPixel(((int) x / 8), y);
    switch(x % 8) {
      case 0:
        status |= oledWriteByte(0x01);
        break;
      case 1:
        status |= oledWriteByte(0x02);
        break;
      case 2:
        status |= oledWriteByte(0x04);
        break;
      case 3:
        status |= oledWriteByte(0x08);
        break;
      case 4:
        status |= oledWriteByte(0x10);
        break;
      case 5:
        status |= oledWriteByte(0x20);
        break;
      case 6:
        status |= oledWriteByte(0x40);
        break;
      case 7:
        status |= oledWriteByte(0x80);
        break;
    }
                
    // A larger usleep value will make the dot move slower
    usleep(10000);
          
    // Clear the current dot on the screen
    status |= oledSetCursorByPixel(((int) x / 8), y);
    status |= oledWriteByte(0x00);
    
    // Clear below for some reason will cause the screen to not print anything
    // status |= oledClear();
  }

  return 0;
 }
	/**
	* A small demo of a dot bouncing inside a 128x64 OLED screen, using the Onion Omega 2. Note this isn't using the
	* OLED expansion, but a cheapo screen I bought from China, using the SSD1306 (as far as I could tell) driver.
	* This was only a personal exercise to see how easy it is to setup, it might be handly to someone else learning!
	*
	* To compile:
	* - install gcc and make (See: https://docs.onion.io/omega2-docs/c-compiler-on-omega.html)
	* - install git (Follow this: https://docs.onion.io/omega2-docs/installing-and-using-git.html)
	* - install python-dev
	* - git clone the i2c exp driver (https://github.com/OnionIoT/i2c-exp-driver)
	* - (At the time of writing) Alter the makefile according to this bug report (https://github.com/OnionIoT/i2c-exp-driver/issues/18)
	* - go into the "i2c-exp-driver" project and compile with `make`
	* - copy bin, include, lib directories to /usr
	* - compile gist below with `gcc bouncing_dot.c -loniondebug -lonioni2c -lonionoledexp`
	* - Run!
	*
	* @author Adam Buckley <[email protected]>
	*/
	// #include <stdio.h>
	#include <unistd.h>
	#include <oled-exp.h>

	int main() {

	// Init the OLED
	int status = oledDriverInit();
	status \|= oledSetDisplayPower(1);

	int x = 0, y = 0;
	int delta_x = 1, delta_y = 1;

	// Run forever
	while(1) {
	x += delta_x;
	y += delta_y;

	// When X hits a boundary on the OLED, flip the delta position
	if (x == 0 \|\| x == 63) {
	delta_x *= -1;
	}

	// Do the same for the y coordinate
	if (y == 0 \|\| y == 127) {
	delta_y *= -1;
	}

	// Set cursor to correct position
	// The way this works is that while the height of the OLED is 64px, there
	// is 8 logical rows, each with 8 addressable pixels. So the code below is just
	// working out where a pixel (e.g x = 57) should be placed

	// See https://docs.onion.io/omega2-docs/oled-expansion-c-library.html#understanding-the-display-1 for more info
	status \|= oledSetCursorByPixel(((int) x / 8), y);
	switch(x % 8) {
	case 0:
	status \|= oledWriteByte(0x01);
	break;
	case 1:
	status \|= oledWriteByte(0x02);
	break;
	case 2:
	status \|= oledWriteByte(0x04);
	break;
	case 3:
	status \|= oledWriteByte(0x08);
	break;
	case 4:
	status \|= oledWriteByte(0x10);
	break;
	case 5:
	status \|= oledWriteByte(0x20);
	break;
	case 6:
	status \|= oledWriteByte(0x40);
	break;
	case 7:
	status \|= oledWriteByte(0x80);
	break;
	}

	// A larger usleep value will make the dot move slower
	usleep(10000);

	// Clear the current dot on the screen
	status \|= oledSetCursorByPixel(((int) x / 8), y);
	status \|= oledWriteByte(0x00);

	// Clear below for some reason will cause the screen to not print anything
	// status \|= oledClear();
	}

	return 0;
	}