Running figure example

This example demonstrates how to draw animated bitmaps to Freetronics Large Dot Matrix Displays. These displays have 512 LED's arranged in a 32x16 matrix and controlled by an SPI interface. The displays are available in red, blue, green, yellow, and white variations.

The first step is to initialize the display:

#include <DMD.h>

DMD display;

We will also need some bitmaps to animate the running figure. We will use static bitmaps stored in program memory. The first frame of the 10-frame animation is:

byte const run1[] PROGMEM = {
    16, 16,
    B00000000, B00001100,
    B00000000, B00011110,
    B00000111, B11111110,
    B00001111, B11111110,
    B00011100, B11111100,
    B00000001, B11111100,
    B00000001, B11110000,
    B00000011, B11111000,
    B00000111, B00011000,
    B00001110, B01110000,
    B00011100, B01100000,
    B00111000, B00000000,
    B01110000, B00000000,
    B01100000, B00000000,
    B01000000, B00000000,
    B00000000, B00000000
};

As can be seen, the bitmap is made up of 0's and 1's; a 1 bit indicates that the corresponding LED will be lit when it is drawn to the dot matrix display. The first two bytes are the width and height of the bitmap in pixels. In this case, the first frame is 16x16 pixels. Other frames in the animation are 18x16 and 13x16.

We store pointers to all of the frames in a common array:

Bitmap::ProgMem frames[] = {
    run1,
    run2,
    run3,
    run4,
    run5,
    run6,
    run7,
    run8,
    run9,
    run10
};
#define NUM_FRAMES  (sizeof(frames) / sizeof(frames[0]))
unsigned int frame = 0;

All that remains is to run the animation loop:

#define ADVANCE_MS  (1000 / NUM_FRAMES)
unsigned long lastFrame;

void setup() {
    lastFrame = millis() - ADVANCE_MS;
}

void loop() {
    if ((millis() - lastFrame) >= ADVANCE_MS) {
        display.clear();
        int x = (32 - pgm_read_byte(frames[frame])) / 2;
        display.drawBitmap(x, 0, frames[frame]);
        lastFrame += ADVANCE_MS;
        frame = (frame + 1) % NUM_FRAMES;
    }
    display.loop();
}

Each time ADVANCE_MS milliseconds expires, we clear the display and draw a bitmap centered on the screen. To help with the centering, we read the width value from the bitmap for the current frame (the height is always 16). We must also call DMD::loop() repeatedly from the application's main loop() function to ensure that the display is kept refreshed.

Sometimes it can be inconvenient to arrange for DMD::loop() to be called regularly. An alternative is to use Timer1 or Timer2 and interrupt-driven display refresh:

#define ADVANCE_MS  (1000 / NUM_FRAMES)

ISR(TIMER1_OVF_vect)
{
    display.refresh();
}

void setup() {
    display.enableTimer1();
}

void loop() {
    display.clear();
    int x = (32 - pgm_read_byte(frames[frame])) / 2;
    display.drawBitmap(x, 0, frames[frame]);
    frame = (frame + 1) % NUM_FRAMES;

    delay(ADVANCE_MS);
}

In the case of Timer2, TIMER2_OVF_vect and enableTimer2() would be used in place of TIMER1_OVF_vect and enableTimer1().

The full source code for the example follows:

/*
 * Copyright (C) 2012 Southern Storm Software, Pty Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include <DMD.h>

DMD display;

// Running stick figure pictures are loosely based on those from this tutorial:
// http://www.fluidanims.com/FAelite/phpBB3/viewtopic.php?f=10&t=102

byte const run1[] PROGMEM = {
    16, 16,
    B00000000, B00001100,
    B00000000, B00011110,
    B00000111, B11111110,
    B00001111, B11111110,
    B00011100, B11111100,
    B00000001, B11111100,
    B00000001, B11110000,
    B00000011, B11111000,
    B00000111, B00011000,
    B00001110, B01110000,
    B00011100, B01100000,
    B00111000, B00000000,
    B01110000, B00000000,
    B01100000, B00000000,
    B01000000, B00000000,
    B00000000, B00000000
};

byte const run2[] PROGMEM = {
    18, 16,
    B00000000, B01110011, B10000000,
    B00000000, B11111111, B10000000,
    B00000000, B00011111, B10000000,
    B00000000, B00111111, B11000000,
    B00000000, B01111011, B11000000,
    B00000000, B11110011, B10000000,
    B00000001, B11100000, B00000000,
    B00000011, B11100000, B00000000,
    B00000111, B01110000, B00000000,
    B01111110, B00111000, B00000000,
    B11111100, B00011100, B00000000,
    B00000000, B00001110, B00000000,
    B00000000, B00000111, B00000000,
    B00000000, B00000011, B10000000,
    B00000000, B00000001, B00000000,
    B00000000, B00000000, B00000000
};

byte const run3[] PROGMEM = {
    18, 16,
    B00000000, B00110000, B00000000,
    B00000000, B01111000, B00000000,
    B00000000, B00011111, B00000000,
    B00000000, B00011111, B00000000,
    B00000000, B00111111, B10000000,
    B00000000, B01111111, B11000000,
    B00000000, B11100011, B10000000,
    B00000001, B11000000, B00000000,
    B00000011, B11100000, B00000000,
    B11111111, B01110000, B00000000,
    B11111110, B00111000, B00000000,
    B00000000, B00011000, B00000000,
    B00000000, B00011100, B00000000,
    B00000000, B00001110, B00000000,
    B00000000, B00000100, B00000000,
    B00000000, B00000000, B00000000
};

byte const run4[] PROGMEM = {
    16, 16,
    B00000001, B11100000,
    B00000011, B11111100,
    B00000000, B00111110,
    B00000000, B01111110,
    B00000000, B11111100,
    B00000001, B10011111,
    B00000011, B00001110,
    B00000011, B00000000,
    B00000011, B10000000,
    B11111111, B10000000,
    B11111000, B11000000,
    B00000001, B11000000,
    B00000011, B10000000,
    B00000111, B00000000,
    B00000110, B00000000,
    B00000100, B00000000
};

byte const run5[] PROGMEM = {
    13, 16,
    B00000000, B00000000,
    B00000000, B00110000,
    B00000111, B11111000,
    B00000111, B11111000,
    B00000111, B11110000,
    B00001111, B11100000,
    B00000111, B00000000,
    B00001111, B00000000,
    B00001111, B00000000,
    B00001111, B10000000,
    B00011100, B00000000,
    B00111000, B00000000,
    B01110000, B00000000,
    B11100000, B00000000,
    B11000000, B00000000,
    B10000000, B00000000
};

byte const run6[] PROGMEM = {
    16, 16,
    B00000000, B00000000,
    B00000000, B00011100,
    B00000000, B00111110,
    B00000001, B11111110,
    B00000000, B11100000,
    B00000001, B11100000,
    B00000001, B11111000,
    B00000011, B00011100,
    B00000110, B00111000,
    B00000110, B01110000,
    B00001100, B00100000,
    B00111000, B00000000,
    B01100000, B00000000,
    B11000000, B00000000,
    B10000000, B00000000,
    B10000000, B00000000
};

byte const run7[] PROGMEM = {
    18, 16,
    B00000000, B00000011, B10000000,
    B00000000, B01111011, B10000000,
    B00000000, B01111111, B10000000,
    B00000000, B00001111, B00100000,
    B00000000, B00011001, B11000000,
    B00000000, B00110000, B11000000,
    B00000000, B01110000, B00000000,
    B00000001, B11110000, B00000000,
    B11111111, B10111000, B00000000,
    B11111111, B00011100, B00000000,
    B00000000, B00001110, B00000000,
    B00000000, B00000111, B00000000,
    B00000000, B00000011, B10000000,
    B00000000, B00000001, B11000000,
    B00000000, B00000000, B01000000,
    B00000000, B00000000, B00000000
};

byte const run8[] PROGMEM = {
    18, 16,
    B00000000, B00000110, B00000000,
    B00000001, B11101111, B00000000,
    B00000001, B11111111, B00000000,
    B00000000, B00111110, B00000000,
    B00000000, B01111111, B11000000,
    B00000000, B11100011, B10000000,
    B00000001, B11000000, B00000000,
    B00000011, B11100000, B00000000,
    B11111111, B01110000, B00000000,
    B11111110, B00111000, B00000000,
    B00000000, B00011100, B00000000,
    B00000000, B00000110, B00000000,
    B00000000, B00000110, B00000000,
    B00000000, B00000111, B00000000,
    B00000000, B00000011, B00000000,
    B00000000, B00000001, B00000000
};

byte const run9[] PROGMEM = {
    16, 16,
    B00000000, B00000000,
    B00000000, B01001110,
    B00000001, B11101110,
    B00000011, B11111110,
    B00000011, B11111110,
    B00000001, B10111100,
    B00000011, B00000000,
    B00000111, B00000000,
    B11111111, B10000000,
    B11111100, B11000000,
    B00000000, B11000000,
    B00000000, B11000000,
    B00000000, B11000000,
    B00000000, B11000000,
    B00000000, B11000000,
    B00000000, B11000000
};

byte const run10[] PROGMEM = {
    13, 16,
    B00000000, B00000000,
    B00000000, B00110000,
    B00000000, B01111000,
    B00000111, B11111000,
    B00001111, B11111000,
    B00000111, B11000000,
    B00001110, B00000000,
    B00001100, B00000000,
    B00001100, B00000000,
    B01111100, B00000000,
    B11111100, B00000000,
    B00011000, B00000000,
    B00110000, B00000000,
    B01110000, B00000000,
    B01100000, B00000000,
    B01000000, B00000000
};

Bitmap::ProgMem frames[] = {
    run1,
    run2,
    run3,
    run4,
    run5,
    run6,
    run7,
    run8,
    run9,
    run10
};
#define NUM_FRAMES  (sizeof(frames) / sizeof(frames[0]))
unsigned int frame = 0;

#define ADVANCE_MS  (1000 / NUM_FRAMES)
unsigned long lastFrame;

void setup() {
    lastFrame = millis() - ADVANCE_MS;
}

void loop() {
    if ((millis() - lastFrame) >= ADVANCE_MS) {
        display.clear();
        int x = (32 - pgm_read_byte(frames[frame])) / 2;
        display.drawBitmap(x, 0, frames[frame]);
        lastFrame += ADVANCE_MS;
        frame = (frame + 1) % NUM_FRAMES;
    }
    display.loop();
}