How to Display a 1d Array of Uncompressed Bitmap Data?

[ishotjr]

Hello!  First of all, let me start by saying thank you for creating this wonderful product - the Gameduino2 is just a delight to use - it's easy to get started, and then as you start to attempt more advanced things, it feels like everything you need has already been anticipated - I love it!  I am working on a project where I hope to grab a bitmap from another device's frame buffer, transmit it to the Gameduino2, and re-assemble and reproduce it there - an external display of sorts...  I started out w/ a quick PoC based on a static image that I ran through gd2asset (after converting that to use Pillow, since the code as downloaded wouldn't work on my system), but what I'd like to do now is basically have a similar 1d array (the frame buffer data is also a 1d array of uint8_t!), but that I can populate myself from the transferred data; I believe that the asset file data is gzipped - I'm hoping I can use something like LOAD_ASSETS() / GD.copy to recreate my source bitmap - am I on the right track, or should I be pursuing a completely different approach?  Thanks in advance for any and all help!!

PS, I did find this:

gameduino2.proboards.com/thread/23/screenshots

which seems almost exactly what I want to do, but in reverse (I want to transmit another device's frame buffer via serial for display on the Gameduino2) - and it actually made me a little wary, since it said it takes about a minute to transmit a full screen at 115K; I w/b sending a much smaller screen to the Gameduino2, but...I'm guessing I should start getting used to the idea that it won't be anything like real-time replication of the device's display, huh...?

[jamesbowman]

This project does something similar, loading an image from an IR sensor into a bitmap:

www.theresistornetwork.com/2014/11/flir-lepton-thermal-imaging-sensor.html

Here is a short program that shows how to set up a bitmap image and set its pixel data. It is using GD.random() to set the pixel data, instead of a real source:



#include <EEPROM.h>
#include <SPI.h>
#include <GD2.h>

void setup() {
 GD.begin();

 // Set up a 320x240 L8 bitmap starting at 0
 GD.BitmapSource(0);
 GD.BitmapLayout(L8, 320, 240);
 GD.BitmapSize(NEAREST, BORDER, BORDER, 320, 240);

 GD.Clear();
 GD.Begin(BITMAPS);
 GD.Vertex2ii((480 - 320) / 2, (272 - 240) / 2);
 GD.swap();
}

void loop() {
 for (long i = 0; i < 76800L; i++)
   GD.wr(i, GD.random());
}


This works fine but GD.wr() for each byte is quite inefficient. This version of loop() uses GD.cmd_memwrite() to do a block write

void loop() {
 union {
   uint8_t  b[4];    // as four bytes
   uint16_t s[2];    // as two shorts
   uint32_t l;       // as a single long
 } u;

 GD.cmd_memwrite(0, 76800L);
 for (int i = 0; i < 19200; i++) {
   u.s[0] = GD.random();
   u.s[1] = GD.random();
   GD.cmd32(u.l);
 }
}



[Renaud]

Hello,

Do you have a sample code for a color bitmap?

Thx,

[jamesbowman]

Sure... if the input data is already RGB565 format (many camera emit RGB565) you can do:



#include <EEPROM.h>
#include <SPI.h>
#include <GD2.h>

void setup() {
 GD.begin();

 // Set up a 320x240 L8 bitmap starting at 0
 GD.BitmapSource(0);
 GD.BitmapLayout(RGB565, 320, 240);
 GD.BitmapSize(NEAREST, BORDER, BORDER, 320, 240);

 GD.Clear();
 GD.Begin(BITMAPS);
 GD.Vertex2ii((480 - 320) / 2, (272 - 240) / 2);
 GD.swap();
}

void loop() {
 union {
   uint8_t  b[4];    // as four bytes
   uint16_t s[2];    // as two shorts
   uint32_t l;       // as a single long
 } u;

 GD.cmd_memwrite(0, 320L * 240 * 2);
 for (int i = 0; i < 240; i++) {
   for (int j = 0; j < 320; j += 2) {
     u.s[0] = GD.random();
     u.s[1] = GD.random();
     GD.cmd32(u.l);
   }
 }
}
If your source data is 8-bit RGB then it needs to be converted to RGB565. This is one way:

unsigned char r, g, b;
uint16_t rgb565 = ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3);