LuaJIT-FFI ShivaVG Proof of Concept Test

package.preload['extern.sdl'] = function()
  local ffi = require 'ffi'

  ffi.cdef [[
    enum {
      SDL_INIT_VIDEO = 0x00000020,
      SDL_OPENGL = 0x00000002,
      SDL_RESIZABLE = 0x00000010,
      SDL_TIMESLICE = 10
    };
    typedef enum {
      SDL_GL_RED_SIZE, SDL_GL_GREEN_SIZE, SDL_GL_BLUE_SIZE, SDL_GL_ALPHA_SIZE,
      SDL_GL_BUFFER_SIZE,
      SDL_GL_DOUBLEBUFFER,
      SDL_GL_DEPTH_SIZE,
      SDL_GL_STENCIL_SIZE,
      SDL_GL_ACCUM_RED_SIZE,
      SDL_GL_ACCUM_GREEN_SIZE,
      SDL_GL_ACCUM_BLUE_SIZE,
      SDL_GL_ACCUM_ALPHA_SIZE,
      SDL_GL_STEREO,
      SDL_GL_MULTISAMPLEBUFFERS,
      SDL_GL_MULTISAMPLESAMPLES,
      SDL_GL_ACCELERATED_VISUAL,
      SDL_GL_SWAP_CONTROL
    } SDL_GLattr;
    typedef enum {
       SDL_NOEVENT = 0,
       SDL_ACTIVEEVENT = 1,
       SDL_KEYDOWN = 2,
       SDL_KEYUP = 3,
       SDL_MOUSEMOTION = 4,
       SDL_MOUSEBUTTONDOWN = 5,
       SDL_MOUSEBUTTONUP = 6,
       SDL_QUIT = 12,
       SDL_SYSWMEVENT = 13,
       SDL_VIDEORESIZE = 16,
       SDL_VIDEOEXPOSE = 17
    } SDL_EventType;
    typedef enum {
      SDLK_ESCAPE = 27,
      SDLK__FORCESIZE = 323
    } SDLKey;
    typedef enum {
      KMOD__FORCESIZE = 0x8000
    } SDLMod;
    typedef union SDL_Event {
      uint8_t type;
      struct { uint8_t type, gain, state; } active;
      struct {
        uint8_t type, which, state;
        struct { uint8_t scancode; SDLKey sym; SDLMod mod; uint16_t unicode; } keysym;
      } key;
      struct {
        uint8_t type, which, state;
        uint16_t x, y; int16_t xrel, yrel;
      } motion;
      struct {
        uint8_t type, which, button, state;
        uint16_t x, y;
      } button;
      struct { uint8_t type; int w, h; } resize;
      struct { uint8_t type; } expose;
      struct { uint8_t type; } quit;
      struct { uint8_t type; int code; void* data1; void* data2; } user;
      struct { uint8_t type; void* msg; } syswm;
    } SDL_Event;
    int SDL_Init(uint32_t flags);
    void* SDL_SetVideoMode(int width, int height, int bpp, uint32_t flags);
    int SDL_GL_SetAttribute(SDL_GLattr, int value);
    void SDL_Delay(uint32_t ms);
    int SDL_PollEvent(SDL_Event*);
    void SDL_GL_SwapBuffers();
  ]]

  return ffi.load 'SDL'

end

package.preload['extern.shivavg'] = function()

  local ffi = require 'ffi'

  ffi.cdef [[
    typedef int VGint;
    typedef float VGfloat;
    typedef enum {
      VG_FALSE = 0,
      VG_TRUE  = 1
    } VGboolean;

    VGboolean vgCreateContextSH(VGint width, VGint height);
    void vgResizeSurfaceSH(VGint width, VGint height);
    void vgDestroyContextSH();

    typedef enum VGParamType {
      VG_CLEAR_COLOR = 0x1121,
      VGPARAMTYPE__FORCESIZE = 0x116A
    } VGParamType;

    void vgSetfv(VGParamType, VGint count, const VGfloat* values);
    void vgClear(VGint x, VGint y, VGint width, VGint height);
  ]]

  return ffi.load 'libOpenVG'

end

local bit = require 'bit'
local ffi = require 'ffi'
local sdl = require 'extern.sdl'
local vg = require 'extern.shivavg'

local screenWidth = 640;
local screenHeight = 480;
local screen;
local blue = ffi.new('VGfloat[4]', 0, 0, 1, 1);

function main()
  local e = ffi.new 'SDL_Event'
  local finished = false

  sdl.SDL_Init(sdl.SDL_INIT_VIDEO);
  sdl.SDL_GL_SetAttribute(sdl.SDL_GL_DOUBLEBUFFER, 1);
  sdl.SDL_GL_SetAttribute(sdl.SDL_GL_STENCIL_SIZE, 1);
  screen = sdl.SDL_SetVideoMode(screenWidth, screenHeight, 0, bit.bor(sdl.SDL_OPENGL, sdl.SDL_RESIZABLE));

  vg.vgCreateContextSH(screenWidth, screenHeight);
  vg.vgSetfv(vg.VG_CLEAR_COLOR, 4, blue);

  while not finished do
    while (sdl.SDL_PollEvent(e) ~= 0) do
      if (e.type == sdl.SDL_QUIT) then
        finished = true;
      elseif (e.type == sdl.SDL_KEYDOWN) then
        if (e.key.keysym.sym == sdl.SDLK_ESCAPE) then
          finished = true;
        end
      elseif (e.type == sdl.SDL_VIDEORESIZE) then
        screenWidth = e.resize.w;
        screenHeight = e.resize.h;
        screen = sdl.SDL_SetVideoMode(screenWidth, screenHeight, 0, bit.bor(sdl.SDL_OPENGL, sdl.SDL_RESIZABLE));
        vg.vgResizeSurfaceSH(screenWidth, screenHeight);
      end
    end
    vg.vgClear(0, 0, screenWidth, screenHeight);
    sdl.SDL_GL_SwapBuffers();
      sdl.SDL_Delay(sdl.SDL_TIMESLICE);
  end
  vg.vgDestroyContextSH();
end

main()