Running triangle_rpi4.c does not require HDMI connection

[hulloanson]

I'm running Buster on RPI4

Some info:

$ uname -a
Linux raspberrypi 5.4.51-v7l+ #1333 SMP Mon Aug 10 16:51:40 BST 2020 armv7l GNU/Linux
$ cat /proc/cpuinfo
...
Hardware	: BCM2711
Revision	: c03112
Model		: Raspberry Pi 4 Model B Rev 1.2

Steps followed:

1. sudo apt-get install libegl1-mesa-dev libgbm-dev libgles2-mesa-dev libdrm-dev -y
2. git clone https://github.com/matusnovak/rpi-opengl-without-x && cd rpi-opengl-without-x
3. gcc -o triangle_rpi4 triangle_rpi4.c -ldrm -lgbm -lEGL -lGLESv2 -I/usr/include/libdrm -I/usr/include/GLES2
4. Execute, no X server, no HDMI output connected.

$./triangle_rpi4 
resolution: 1680x720
Initialized EGL version: 1.4
GL Viewport size: 1680x720

[matusnovak]

Hi @hulloanson

Thank you for this information. I must have done something wrong in my setup that required a hdmi output. I am glad I was wrong.

I will update the Readme.