-- vim: set ts=3 et:

print('_VERSION = ' .. _VERSION)

require 'luagl'
require 'luaglut'
require 'memarray'

print('luagl.VERSION = '   .. luagl.VERSION)
print('luaglut.VERSION = ' .. luaglut.VERSION)

local quit = false
local fps = 15
local fps_str = ''
local msec = 1000 / fps
local frames = 0
local start_time
local elapsed_time
local ppm, width, height

local draw_mode = 'solid'
local fps_mode  = 'fixed'

local function glutBitmapString(font, str)
   for i = 1, string.len(str) do
      glutBitmapCharacter(font, string.byte(str, i))
   end
end

function load_texture(fname)
   local f, width, height, depth, data

   f = assert(io.open(fname, 'rb'))
   assert(f:read('*l') == 'P6')
   width = f:read('*n')
   height = f:read('*n')
   depth = f:read('*l')
   depth = f:read('*l')
   data = f:read('*a')
   f:close()

   local ppm = memarray('uchar', width * height * 3)
   for y = 1, height do
      local dst_idx = (height - y) * width * 3
      local src_idx = (y - 1) * width * 3
      for x = 0, width - 1 do
         ppm[dst_idx + 3*x + 0] = string.byte(data, src_idx + 3*x + 1)
         ppm[dst_idx + 3*x + 1] = string.byte(data, src_idx + 3*x + 2)
         ppm[dst_idx + 3*x + 2] = string.byte(data, src_idx + 3*x + 3)
      end
   end

   return ppm, width, height
end

local function set_material_clay()
   glMaterialfv(GL_FRONT, GL_AMBIENT,  {0.2125, 0.1275, 0.054, 1.0})
   glMaterialfv(GL_FRONT, GL_DIFFUSE,  {0.514, 0.4284, 0.18144, 1.0})
   glMaterialfv(GL_FRONT, GL_SPECULAR, {0.393548, 0.271906, 0.166721, 1.0})
   glMaterialf(GL_FRONT, GL_SHININESS, 0.2 * 128.0)

   glMaterialfv(GL_BACK, GL_AMBIENT,  {0.1, 0.18725, 0.1745, 1.0})
   glMaterialfv(GL_BACK, GL_DIFFUSE,  {0.396, 0.74151, 0.69102, 1.0})
   glMaterialfv(GL_BACK, GL_SPECULAR, {0.297254, 0.30829, 0.306678, 1.0})
   glMaterialf(GL_BACK, GL_SHININESS, 0.1 * 128.0)

   glEnable(GL_LIGHT0)
   glLightfv(GL_LIGHT0, GL_AMBIENT, {0.2, 0.2, 0.2, 1})
   glLightfv(GL_LIGHT0, GL_DIFFUSE, {1, 1, 1, 1})
   glLightfv(GL_LIGHT0, GL_POSITION, {0.0, 1.0, 0.0, 0.0})

   glEnable(GL_LIGHT1)
   glLightfv(GL_LIGHT1, GL_AMBIENT, {0.2, 0.2, 0.2, 1})
   glLightfv(GL_LIGHT1, GL_DIFFUSE, {1, 1, 1, 1})
   glLightfv(GL_LIGHT1, GL_POSITION, {1.0, 0.0, 1.0, 0.0})

   glLightModelf(GL_LIGHT_MODEL_TWO_SIDE, GL_FALSE)
   glFrontFace(GL_CW)
end

function resize_func(w, h)
   local ratio = w / h
   glMatrixMode(GL_PROJECTION)
   glLoadIdentity()
   glViewport(0,0,w,h)
   gluPerspective(45,ratio,1,1000)
   glMatrixMode(GL_MODELVIEW)
   glLoadIdentity()
   set_material_clay()
   glEnable(GL_DEPTH_TEST)
   glEnable(GL_NORMALIZE)
   glTexImage2D(GL_TEXTURE_2D, 0, 3, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, ppm:ptr())
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP)
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP)
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_DECAL)
   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL)
   glEnable(GL_TEXTURE_2D)
end

function timer_func()
   if quit then return end
   if fps_mode == 'fixed' then
      glutSetWindow(window)
      glutTimerFunc(msec, timer_func, 0)
      glutPostRedisplay()
   end
end

local angle = 0
local angle2 = 0

function display_func()
   if quit then return end

   local elapsed_time = glutGet(GLUT_ELAPSED_TIME) - start_time

   angle = angle + 200 / (msec)
   angle2 = angle2 + 170 / (msec)

   glClear(GL_COLOR_BUFFER_BIT + GL_DEPTH_BUFFER_BIT)

   glMatrixMode(GL_MODELVIEW)
   glPushMatrix()
   glTranslated(0,0,-5)
   glRotated(angle, 0, 1, 0)
   glRotated(angle2, 0, 0, 1)
   glColor3d(1,0,0)
   if draw_mode == 'wireframe' then
      glutWireTeapot(0.75)
   else
      glEnable(GL_LIGHTING)
      glutSolidTeapot(0.75)
      glDisable(GL_LIGHTING)
   end
   glPopMatrix()

   glDisable(GL_TEXTURE_2D)
   glMatrixMode(GL_PROJECTION)
   glPushMatrix()
   glLoadIdentity()
   glOrtho(0, glutGet(GLUT_WINDOW_WIDTH), 0, glutGet(GLUT_WINDOW_HEIGHT), -1, 1)
   glColor3d(1,1,1)
   glRasterPos2d(10,10)
   glutBitmapString(GLUT_BITMAP_HELVETICA_12, fps_str)
   glPopMatrix()
   glEnable(GL_TEXTURE_2D)

   glutSwapBuffers()

   if fps_mode == 'fastest' then glutPostRedisplay() end

   frames = frames + 1

   if elapsed_time > 1000 then
      fps_str = 'measured fps: ' .. frames * 1000 / elapsed_time
      print(fps_str)
      start_time = start_time + elapsed_time
      frames = 0
   end
end

function keyboard_func(key,x,y)
   if key == 27 then
      quit = true
      glutDestroyWindow(window)
      os.exit(0)
   end
end

ppm, width, height = load_texture('lua.ppm')

glutInit(arg)
glutInitDisplayMode(GLUT_RGB + GLUT_DOUBLE + GLUT_DEPTH)
if arg then title = arg[0] else title = "glut" end
window = glutCreateWindow(title)
glutDisplayFunc(display_func)
glutKeyboardFunc(keyboard_func)
glutReshapeFunc(resize_func)
glutTimerFunc(msec, timer_func, 0)

--[[
glutTimerFunc(2000,
   function(value)
      io.write('another timer called with value = ',value,'\n')
   end,
   2)
--]]

local menu1 = glutCreateMenu(function(value) print('submenu callback ' .. value) end)
glutAddMenuEntry('one', 1)
glutAddMenuEntry('two', 2)

local mainmenu = glutCreateMenu(function(value) print('mainmenu callback ' .. value) end)
glutAddMenuEntry('wireframe', function() draw_mode = 'wireframe' end)
glutAddMenuEntry('solid', function() draw_mode = 'solid' end)

glutAddMenuEntry('fastest FPS',
   function()
      fps_mode = 'fastest'
      glutSetWindow(window)
      glutPostRedisplay()
   end)

glutAddMenuEntry('fixed FPS(' .. fps .. ')',
   function()
      fps_mode = 'fixed'
      glutTimerFunc(msec, timer_func, 0)
   end)

glutAddSubMenu('submenu test', menu1)

glutAddMenuEntry('quit',
   function()
      quit = true
      glutDestroyWindow(window)
      os.exit(0)
    end)

glutAttachMenu(GLUT_LEFT_BUTTON)
start_time = glutGet(GLUT_ELAPSED_TIME)
glutMainLoop()