Dart + SDL2 crash example

app.dart

import 'dart:ffi';
import 'dart:convert';

void main() {  
  var sdl = DynamicLibrary.open('SDL2.dll');
  loadSDL(sdl);
  
  sdlInit(SDL_INIT_VIDEO);

  var title = CString.fromUtf8('Dart FFI + SDL');
  var window = sdlCreateWindow(title, 100, 100, 600, 400, SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL);
      
  var renderer = sdlCreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
  sdlSetRenderDrawColor(renderer, 0, 179, 252, 0); 
  
  var event = SDL_Event(0); 
  var exit = false;
  while (!exit) {
    while (sdlPollEvent(event) != 0) {

    }

    if (event.type == SDL_QUIT) { exit = true; }

    sdlRenderClear(renderer);
    sdlRenderPresent(renderer);
  }    
}

const int SDL_INIT_VIDEO = 0x00000020;
const int SDL_WINDOW_RESIZABLE = 0x00000020;
const int SDL_WINDOW_OPENGL = 0x00000002;
const int SDL_QUIT           = 0x100;
const int SDL_RENDERER_ACCELERATED = 0x00000002;

typedef SDL_Init_Native = Int32 Function(Uint32);
typedef SDL_Init = int Function(int);

typedef SDL_CreateWindow_Native = Int64 Function(CString, Int32, Int32, Int32, Int32, Uint32); 
typedef SDL_CreateWindow = int Function(CString, int, int, int, int, int); 

typedef SDL_PollEvent_Native = Int32 Function(SDL_Event);
typedef SDL_PollEvent = int Function(SDL_Event); 

typedef SDL_CreateRenderer_Native = IntPtr Function(IntPtr window, Int32 index, Int32 flags);
typedef SDL_CreateRenderer = int Function(int window, int index, int flags);

typedef SDL_SetRenderDrawColor_Native = Int32 Function(IntPtr renderer, Int8 r, Int8 g, Int8 b, Int8 a);
typedef SDL_SetRenderDrawColor = int Function(int renderer, int r, int g, int b, int a);

typedef SDL_RenderClear_Native = Int32 Function(IntPtr renderer);
typedef SDL_RenderClear = int Function(int renderer);

typedef SDL_RenderPresent_Native = Void Function(IntPtr renderer);
typedef SDL_RenderPresent = void Function(int renderer);

@struct
class SDL_Event extends Pointer<Void> {
  @Uint32()
  int type;
  @Uint32()
  int timestamp;
  @Uint32()
  int windowID;
  @Uint8()
  int event;
  @Uint8()
  int p1;
  @Uint8()
  int p2;
  @Uint8()
  int p3;
  @Int32()
  int data1;
  @Int32()
  int data2;

  @Uint32()
  int p4;
  @Uint32()
  int p5;
  @Uint32()
  int p6;
  @Uint32()
  int p7;
  @Uint32()
  int p8;
  @Uint32()
  int p9;
  @Uint32()
  int p10;
  @Uint32()
  int p11;

  external static int sizeOf();
 
  factory SDL_Event(int type) {
    SDL_Event result = allocate<Uint8>(count: 1 * sizeOf()).cast()
      ..type = type;
    return result;
  }
}

SDL_Init sdlInit;
SDL_CreateWindow sdlCreateWindow;
SDL_CreateRenderer sdlCreateRenderer;
SDL_SetRenderDrawColor sdlSetRenderDrawColor;
SDL_RenderClear sdlRenderClear;
SDL_RenderPresent sdlRenderPresent;
SDL_PollEvent sdlPollEvent;

void loadSDL(DynamicLibrary sdl) {
  sdlInit = sdl.lookupFunction<SDL_Init_Native, SDL_Init>('SDL_Init');
  sdlCreateWindow = sdl.lookupFunction<SDL_CreateWindow_Native, SDL_CreateWindow>('SDL_CreateWindow');
  sdlCreateRenderer = sdl.lookupFunction<SDL_CreateRenderer_Native, SDL_CreateRenderer>('SDL_CreateRenderer');
  sdlSetRenderDrawColor = sdl.lookupFunction<SDL_SetRenderDrawColor_Native, SDL_SetRenderDrawColor>('SDL_SetRenderDrawColor');
  sdlRenderClear = sdl.lookupFunction<SDL_RenderClear_Native, SDL_RenderClear>('SDL_RenderClear');
  sdlRenderPresent = sdl.lookupFunction<SDL_RenderPresent_Native, SDL_RenderPresent>('SDL_RenderPresent');
  sdlPollEvent = sdl.lookupFunction<SDL_PollEvent_Native, SDL_PollEvent>('SDL_PollEvent');
}

class CString extends Pointer<Uint8> {
  CString elementAt(int index) => super.elementAt(index).cast();
  
  factory CString.fromUtf8(String s) {
    CString result = allocate<Uint8>(count: s.length + 1).cast();
    List<int> units = Utf8Encoder().convert(s);
    for (int i = 0; i < s.length; i++) result.elementAt(i).store(units[i]);
    result.elementAt(s.length).store(0);
    return result;
  }
}