docker-extract.sh

#!/bin/bash
id=$(docker create $1)
mkdir -p build
docker cp $id:$2 build/
docker rm -v $id

Dockerfile

FROM debian:11-slim

RUN apt-get update && apt-get -y install debootstrap
RUN /usr/sbin/debootstrap --no-check-gpg --arch armel --foreign jessie /tmp/deb8arm http://archive.debian.org/debian/
RUN chroot /tmp/deb8arm /debootstrap/debootstrap --second-stage
RUN echo 'deb http://archive.debian.org/debian jessie-backports main' >> /tmp/deb8arm/etc/apt/sources.list
RUN chroot /tmp/deb8arm apt-get update
RUN chroot /tmp/deb8arm apt-get -y --force-yes install build-essential libdirectfb-dev

# may need pkg-config here?
RUN chroot /tmp/deb8arm apt-get -y --force-yes install -t jessie-backports cmake pkg-config

RUN wget https://github.com/libsdl-org/SDL/releases/download/release-2.26.4/SDL2-2.26.4.tar.gz
RUN tar xf SDL2-2.26.4.tar.gz

# next up: remove version check for libdirectfb. Then, see if compiling an actual 1.2.8 helps
RUN mv SDL2-2.26.4 /tmp/deb8arm/root

# maybe we can set other things to OFF to reduce library size
RUN chroot /tmp/deb8arm sh -c 'cd /root/SDL2-2.26.4 && mkdir build && cd build && cmake -DSDL_DIRECTFB=ON .. && make install'

COPY sdl-example.c /tmp/deb8arm/root/
RUN chroot /tmp/deb8arm sh -c 'cd /root && CFLAGS=`sdl2-config --cflags` LDFLAGS=`sdl2-config --libs` make sdl-example'

# now try LVGL
#RUN chroot /tmp/deb8arm sh -c 'apt-get -y --force-yes install git'
#RUN chroot /tmp/deb8arm sh -c 'git clone --depth 5 https://github.com/lvgl/lvgl'
#RUN chroot /tmp/deb8arm sh -c 'git clone --depth 5 https://github.com/lvgl/lv_drivers'
#RUN chroot /tmp/deb8arm sh -c 'git clone --depth 5 https://github.com/lvgl/lv_examples'
#
#RUN chroot /tmp/deb8arm sh -c 'mkdir lvgl-helloworld'
#RUN chroot /tmp/deb8arm sh -c 'mv lvgl lv_drivers lv_examples lvgl-helloworld/'
#RUN chroot /tmp/deb8arm sh -c 'cd lvgl-helloworld && cp lvgl/lv_conf_template.h lv_conf.h'
#RUN chroot /tmp/deb8arm sh -c 'cd lvgl-helloworld && cp lv_drivers/lv_drv_conf_template.h lv_drv_conf.h'
##RUN chroot /tmp/deb8arm sh -c 'cat lvgl-helloworld/lv_conf.h'
##RUN chroot /tmp/deb8arm sh -c 'cat lvgl-helloworld/lv_drv_conf.h'
#RUN chroot /tmp/deb8arm sh -c 'sed -i "s/#if 0/#if 1/" lvgl-helloworld/*.h'
#RUN chroot /tmp/deb8arm sh -c 'sed -i "s/LV_COLOR_DEPTH 16/LV_COLOR_DEPTH 32/" lvgl-helloworld/lv_conf.h'
#RUN chroot /tmp/deb8arm sh -c 'sed -i "s/#  define USE_FBDEV           0/#define USE_FBDEV 1/" lvgl-helloworld/lv_drv_conf.h'
#RUN chroot /tmp/deb8arm sh -c 'pwd'
#
#COPY lvgl-helloworld/main.c /tmp/deb8arm/lvgl-helloworld/
#
#RUN chroot /tmp/deb8arm sh -c 'cd /lvgl-helloworld && make CPPFLAGS=-I. main'


# now try the LVGL fb example
RUN chroot /tmp/deb8arm sh -c 'apt-get -y --force-yes install git'
RUN chroot /tmp/deb8arm sh -c 'git clone https://github.com/Habbie/lv_port_linux_frame_buffer.git # 3'
RUN chroot /tmp/deb8arm sh -c 'cd lv_port_linux_frame_buffer/ && git submodule update --init --recursive'
RUN chroot /tmp/deb8arm sh -c 'cd lv_port_linux_frame_buffer && make -j12'
RUN chroot /tmp/deb8arm sh -c 'cd lv_port_linux_frame_buffer && find . -name demo'

sdl-example.c

#include <SDL2/SDL.h>
//#include <SDL2/SDL_image.h>
#include <SDL2/SDL_timer.h>

int main(int argc, char *argv[])
{

	// returns zero on success else non-zero
	if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
		printf("error initializing SDL: %s\n", SDL_GetError());
		exit(1);
	}
	printf("x");
	SDL_Window* win = SDL_CreateWindow("GAME", // creates a window
									SDL_WINDOWPOS_CENTERED,
									SDL_WINDOWPOS_CENTERED,
									1000, 1000, 0);
	printf("win=%x\n", win);
	if(win == NULL) {
		printf("error initializing SDL: %s\n", SDL_GetError());
		exit(1);
	}


	printf("y");
	// triggers the program that controls
	// your graphics hardware and sets flags
	Uint32 render_flags = 0; // SDL_RENDERER_ACCELERATED;

	printf("z");
	// creates a renderer to render our images
	SDL_Renderer* rend = SDL_CreateRenderer(win, -1, render_flags);
	printf("q");

	// creates a surface to load an image into the main memory
//	SDL_Surface* surface;

	// please provide a path for your image
//	surface = IMG_Load("path");

	// loads image to our graphics hardware memory.
//	SDL_Texture* tex = SDL_CreateTextureFromSurface(rend, surface);

	// clears main-memory
	//SDL_FreeSurface(surface);

	printf("r");
	// let us control our image position
	// so that we can move it with our keyboard.
	SDL_Rect dest;

	// connects our texture with dest to control position
	//SDL_QueryTexture(tex, NULL, NULL, &dest.w, &dest.h);

	// adjust height and width of our image box.
	dest.w /= 6;
	dest.h /= 6;

	// sets initial x-position of object
	dest.x = (1000 - dest.w) / 2;

	// sets initial y-position of object
	dest.y = (1000 - dest.h) / 2;

	// controls animation loop
	int close = 0;

	// speed of box
	int speed = 300;

	printf("a");
	// animation loop
	while (!close) {
	printf("b");
		SDL_Event event;

		// Events management
		while (SDL_PollEvent(&event)) {
	printf("c");
			switch (event.type) {

			case SDL_QUIT:
				// handling of close button
				close = 1;
				break;

			case SDL_KEYDOWN:
				// keyboard API for key pressed
				switch (event.key.keysym.scancode) {
				case SDL_SCANCODE_W:
				case SDL_SCANCODE_UP:
					dest.y -= speed / 30;
					break;
				case SDL_SCANCODE_A:
				case SDL_SCANCODE_LEFT:
					dest.x -= speed / 30;
					break;
				case SDL_SCANCODE_S:
				case SDL_SCANCODE_DOWN:
					dest.y += speed / 30;
					break;
				case SDL_SCANCODE_D:
				case SDL_SCANCODE_RIGHT:
					dest.x += speed / 30;
					break;
				default:
					break;
				}
			}
		}

		// right boundary
		if (dest.x + dest.w > 1000)
			dest.x = 1000 - dest.w;

		// left boundary
		if (dest.x < 0)
			dest.x = 0;

		// bottom boundary
		if (dest.y + dest.h > 1000)
			dest.y = 1000 - dest.h;

		// upper boundary
		if (dest.y < 0)
			dest.y = 0;

		// clears the screen
	printf("e");
		SDL_RenderClear(rend);
	printf("f");
		//SDL_RenderCopy(rend, tex, NULL, &dest);

		// triggers the double buffers
		// for multiple rendering
		SDL_RenderPresent(rend);
	printf("g");

		// calculates to 60 fps
		SDL_Delay(1000 / 60);
	}

	
	printf("h");
	// destroy texture
	//SDL_DestroyTexture(tex);

	// destroy renderer
	SDL_DestroyRenderer(rend);

	// destroy window
	SDL_DestroyWindow(win);
	
	// close SDL
	SDL_Quit();

	return 0;
}