bminit.lua

-- Libraries
local image = require("image")
local gl = require("gl")
local glu = require("glu")
local glut = require("glut")
local mesh = require("mesh")
local bm = require("bm")

local pairs = pairs
local string = string
local io = io
local math = math
local os = os

-- Functions
local abs = math.abs

local cos = math.cos

local exp = math.exp

local floor = math.floor

local glBegin = gl.glBegin
local glCallList = gl.glCallList
local glClear = gl.glClear
local glClearColor = gl.glClearColor
local glColord = gl.glColord
local glDepthMask = gl.glDepthMask
local glDisable = gl.glDisable
local glEnable = gl.glEnable
local glEnd = gl.glEnd
local glEndList = gl.glEndList
local glFlush = gl.glFlush
local glGenLists = gl.glGenLists
local glGetBooleanv = gl.glGetBooleanv
local glGetDoublev = gl.glGetDoublev
local glLoadIdentity = gl.glLoadIdentity
local glMaterial = gl.glMaterial
local glMatrixMode = gl.glMatrixMode
local glNewList = gl.glNewList
local glOrtho = gl.glOrtho
local glPixelZoom = gl.glPixelZoom
local glPointSize = gl.glPointSize
local glPopMatrix = gl.glPopMatrix
local glPushMatrix = gl.glPushMatrix
local glRasterPosd = gl.glRasterPosd
local glReadPixels = gl.glReadPixels
local glRotated = gl.glRotated
local glScaled = gl.glScaled
local glTranslated = gl.glTranslated
local glVertexd = gl.glVertexd
local glViewport = gl.glViewport

local gluPerspective = glu.gluPerspective
local gluUnProject = glu.gluUnProject

local glutBitmapCharacter = glut.glutBitmapCharacter
local glutFullScreen = glut.glutFullScreen
local glutGet = glut.glutGet
local glutGetModifiers = glut.glutGetModifiers
local glutPostRedisplay = glut.glutPostRedisplay
local glutReshapeWindow = glut.glutReshapeWindow
local glutSwapBuffers = glut.glutSwapBuffers
local glutWireCube = glut.glutWireCube

local max = math.max
local min = math.min

local pi = math.pi

local sin = math.sin
local sqrt = math.sqrt

local unpack = table.unpack

-- Boolean values
local GL_FALSE			= 0x0000
local GL_TRUE			= 0x0001

-- Data types
local GL_FLOAT			= 0x1406

-- Primitives
local GL_POINTS			= 0x0000
local GL_LINES			= 0x0001
local GL_QUADS			= 0x0007

-- Matrix Mode
local GL_MODELVIEW		= 0x1700
local GL_PROJECTION		= 0x1701

-- Lines
local GL_LINE_SMOOTH		= 0x0B20

-- Polygons
local GL_POINT			= 0x1B00
local GL_LINE			= 0x1B01
local GL_FILL			= 0x1B02

-- Depth buffer
local GL_DEPTH_TEST		= 0x0B71
local GL_DEPTH_COMPONENT	= 0x1902

-- Lighting
local GL_LIGHTING		= 0x0B50
local GL_DIFFUSE		= 0x1201
local GL_FRONT_AND_BACK		= 0x0408

-- Feedback
local GL_2D			= 0x0600

-- Fog
local GL_LINEAR			= 0x2601

-- Buffers, Pixel Drawing/Reading
local GL_LEFT			= 0x0406
local GL_RIGHT			= 0x0407
local GL_RGBA			= 0x1908

-- Pixel Mode / Transfer
local GL_UNPACK_ALIGNMENT	= 0x0CF5

-- Texture mapping
local GL_TEXTURE_ENV		= 0x2300
local GL_TEXTURE_ENV_MODE	= 0x2200
local GL_TEXTURE_1D		= 0x0DE0
local GL_TEXTURE_WRAP_S		= 0x2802
local GL_TEXTURE_MAG_FILTER	= 0x2800
local GL_TEXTURE_MIN_FILTER	= 0x2801
local GL_TEXTURE_GEN_S		= 0x0C60
local GL_TEXTURE_GEN_MODE	= 0x2500
local GL_TEXTURE_COMPONENTS	= 0x1003
local GL_LINEAR_MIPMAP_LINEAR	= 0x2703
local GL_OBJECT_LINEAR		= 0x2401
local GL_OBJECT_PLANE		= 0x2501
local GL_MODULATE		= 0x2100
local GL_REPEAT			= 0x2901
local GL_S			= 0x2000

-- glPush/PopAttrib bits
local GL_DEPTH_BUFFER_BIT	= 0x00000100
local GL_COLOR_BUFFER_BIT	= 0x00004000

-- Display Lists
local GL_COMPILE		= 0x1300

local GLUT_DOWN			= 0
local GLUT_UP			= 1
local GLUT_LEFT			= 0
local GLUT_WINDOW_X		= 100
local GLUT_WINDOW_Y		= 101
local GLUT_WINDOW_WIDTH		= 102
local GLUT_WINDOW_HEIGHT	= 103
local GLUT_SCREEN_WIDTH		= 200
local GLUT_SCREEN_HEIGHT	= 201
local GLUT_WINDOW_RGBA		= 116
local GLUT_WINDOW_CURSOR	= 122
local GLUT_ACTIVE_SHIFT		= 1
local GLUT_ACTIVE_CTRL		= 2
local GLUT_ACTIVE_ALT		= 4

local browser_path, pager_path
	= "firefox", "firefox"
local mesh_obj = mesh.load("data/cortex.mesh")
local labels = {}
local fovy_deg, camera_distance, znear, zfar, x_angle_deg, y_angle_deg, label_point_size
	= 45.0, 2.0, 1.0, 1e5, 0.0, 0.0, 5.0
local camera_pivot, camera_offset
	= {0, 0, 0}, {0, 0, 0}
local mouse_xi, mouse_yi
	= 0, 0
local axes_color, stripe_color, mesh_color, horizontal_plane_color, coronal_plane_color, sagittal_plane_color, label_color
	= {0, 0, 0, 1}, {1, 0, 0, 1}, {0.9, 0.9, 0.9, 1.0}, {0.0, 0.0, 0.8, 0.3}, {0.7, 0.0, 0.0, 0.3}, {0.7, 0.4, 0.0, 0.3}, {1.0, 6.0, 0.0, 1.0}
local draw_mode = GL_FILL
local locked_position = nil
local scene_box = {mesh_obj:get_bounds()}
local kb_cmd_mode = false

local command = ""				-- command being entered by the user
local candy_striping, doing_transparency, drawing_thumbnails, ctrl_is_pressed, shift_is_pressed
	= false, false, true, false, false

local warn = function(...)
	io.stderr:write(string.format(...) .. "\n")
end

local reverse = function(t)

	local len_t = #t

	for i = 1, len_t / 2  do
		t[i], t[len_t - i + 1] = t[len_t - i + 1], t[i]
	end
end

local load_thumbnails = function(orient)

	local bm_thumbnails, bm_names
		= {}, {}
	local bm_max_width, bm_max_height, i
		= 1, 1, 1
	local file = io.open("thumbnails/" .. orient .. "-labelled/names")

	for filename in file:lines() do
		bm_names[i] = filename:sub(1, -5)
		bm_thumbnails[i] = image.load("thumbnails/" .. orient .. "-labelled/" .. filename)

		local width, height = bm_thumbnails[i]:get_size()

		bm_max_width  = max(bm_max_width,  width)
		bm_max_height = max(bm_max_height, height)
		i = i + 1
	end

	bm[orient .. "_thumbnails"] = bm_thumbnails
	bm[orient .. "_names"] = bm_names
	bm[orient .. "_max_width"] = bm_max_width
	bm[orient .. "_max_height"] = bm_max_height
end

-- Load coronal thumbnails
load_thumbnails("coronal")
reverse(bm.coronal_names)
reverse(bm.coronal_thumbnails)

-- Load horizontal thumbnails
load_thumbnails("horizontal")

-- Load sagittal thumbnails
load_thumbnails("sagittal")

-- wx, wy, wz are the returned world coordinates
-- Reference: redbook/unproject.c & one of the NeHe demos
-- The name is a bit misleading, since the result can be
-- different if the position is locked.
local get_mouse_location = function()

	if locked_position ~= nil then
		return unpack(locked_position)
	end

	local real_x, real_y
		= mouse_xi, glutGet(GLUT_WINDOW_HEIGHT) - mouse_yi - 1

	return gluUnProject(real_x, real_y, glReadPixels(real_x, real_y, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT))
end

local center = { (scene_box[1] + scene_box[4]) / 2, (scene_box[2] + scene_box[5]) / 2, (scene_box[3] + scene_box[6]) / 2 }
local edges = { scene_box[4] - scene_box[1], scene_box[5] - scene_box[2], scene_box[6] - scene_box[3] }

local get_indexes_from_mouse = function()

	local x, y, z = get_mouse_location()

	return floor((#bm.coronal_names)    * (z - scene_box[3]) / edges[3]),
	       floor((#bm.horizontal_names) * (y - scene_box[2]) / edges[2]),
	       floor((#bm.sagittal_names)   * (x - scene_box[1]) / edges[1])
end

-------
-- Etc.
-------

local draw_bitmap_string = function(font, s, x, y, z)

	if x ~= nil then
		if z ~= nil then
			glRasterPosd(x, y, z)
		else
			glDepthMask(false)
			glRasterPosd(x, y)
			glDepthMask(true)
		end
	end

	for i = 1, s:len() do
		glutBitmapCharacter(font, s:byte(i))
	end
end

local show_pos = function(x, y, z)
	draw_bitmap_string("h12", ("(%3.1f, %3.1f, %3.1f) [mm]"):format(x, y, z), x, y, z)
end

local draw_box_list = glGenLists(1)

do
	glNewList(draw_box_list, GL_COMPILE)
	glPushMatrix()
	glTranslated(center[1], center[2], center[3], 1)
	glScaled(edges[1], edges[2], edges[3])
	glutWireCube(1.0)
	glPopMatrix()
	show_pos(scene_box[1], scene_box[2], scene_box[3])
	show_pos(scene_box[4], scene_box[5], scene_box[6])
	glEndList()
end

local set_up_3D_viewport_and_matrices = function()

	local w, h = max(1, glutGet(GLUT_WINDOW_WIDTH)), max(1, glutGet(GLUT_WINDOW_HEIGHT))
	local width_of_3d_area = ({ [true] = w - bm.coronal_max_width, [false] = w })[drawing_thumbnails]

	glViewport(0, 0, width_of_3d_area - 1, h - 1)

	-- Do transformations to implement the camera
	glMatrixMode(GL_PROJECTION)
	glLoadIdentity()
	gluPerspective(fovy_deg, width_of_3d_area / h, znear, zfar)
	glMatrixMode(GL_MODELVIEW)
	glLoadIdentity()

	local x, y, z
		= unpack(camera_offset)

	z = z - camera_distance
	glTranslated(x, y, z)
	glRotated(x_angle_deg, -1.0, 0.0, 0.0)
	glRotated(y_angle_deg,  0.0, 1.0, 0.0)
	x, y, z = unpack(camera_pivot)
	glTranslated(-x, -y, -z)
end

on_display = function()

	if doing_transparency == false then
		glEnable(GL_DEPTH_TEST)
	end

	glClearColor(1.0, 1.0, 1.0, 1.0)
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

	set_up_3D_viewport_and_matrices()

	glMaterial(GL_FRONT_AND_BACK, GL_DIFFUSE, unpack(mesh_color))
	glEnable(GL_LIGHTING)
	glPushMatrix()

	if candy_striping == true then
		glEnable(GL_TEXTURE_1D)
		glEnable(GL_TEXTURE_GEN_S)
	end

	mesh_obj:draw()

	if candy_striping == true then
		glDisable(GL_TEXTURE_1D)
		glDisable(GL_TEXTURE_GEN_S)
	end

	glPopMatrix()
	glDisable(GL_LIGHTING)

	glColord(unpack(axes_color))
	glCallList(draw_box_list)

	local x, y, z = get_mouse_location()

	if locked_position ~= nil then

		glDepthMask(false)

		glBegin(GL_QUADS)

		-- coronal
		glColord(unpack(coronal_plane_color))
		glVertexd(scene_box[1], scene_box[2], z)
		glVertexd(scene_box[1], scene_box[5], z)
		glVertexd(scene_box[4], scene_box[5], z)
		glVertexd(scene_box[4], scene_box[2], z)

		-- horizontal
		glColord(unpack(horizontal_plane_color))
		glVertexd(scene_box[1], y, scene_box[3])
		glVertexd(scene_box[1], y, scene_box[6])
		glVertexd(scene_box[4], y, scene_box[6])
		glVertexd(scene_box[4], y, scene_box[3])

		-- sagittal
		glColord(unpack(sagittal_plane_color))
		glVertexd(x, scene_box[2], scene_box[3])
		glVertexd(x, scene_box[2], scene_box[6])
		glVertexd(x, scene_box[5], scene_box[6])
		glVertexd(x, scene_box[5], scene_box[3])

		glEnd()

		-- Draw lines where the planes of section intersect
		glBegin(GL_LINES)
		glColord(0.0, 0.0, 0.0, 1.0)	-- back to black
		glVertexd(x, y, scene_box[3])
		glVertexd(x, y, scene_box[6])
		glVertexd(scene_box[1], y, z)
		glVertexd(scene_box[4], y, z)
		glVertexd(x, scene_box[2], z)
		glVertexd(x, scene_box[5], z)
		glEnd()

		glDepthMask(true)
	end

	glDisable(GL_DEPTH_TEST)
	glPushMatrix()
	glLoadIdentity()
	glMatrixMode(GL_PROJECTION)
	glPushMatrix()
	glLoadIdentity()

	local w, h
		= max(1, glutGet(GLUT_WINDOW_WIDTH)), max(1, glutGet(GLUT_WINDOW_HEIGHT))

	glOrtho(1, w, 1, h, -1, 1)

	local str = nil

	-- Only draw the 3D mouse coords if the mouse is probably over the
	-- surface.  This hack on the next line should be replaced with something
	-- smarter.
	if x ^ 2 + y ^ 2 + z ^ 2 < (0.75 * zfar) ^ 2 then
		str = ("Mouse location: (%4.3f, %4.3f, %4.3f)"):format(x, y, z)
		draw_bitmap_string("h12", str, 10, h - 20)
	end

	-- More here: print out other info of interest: frame rate, etc.
	if kb_cmd_mode == true then
		draw_bitmap_string("h12", "lua> " .. command .. "|", 10, 10)
	end

	glPopMatrix()
	glMatrixMode(GL_MODELVIEW)
	glPopMatrix()

	if glGetBooleanv(GL_DEPTH_TEST) == GL_TRUE then
		glEnable(GL_DEPTH_TEST)
	end

	if #labels > 0 then
		glColord(unpack(label_color))

		for _, L in pairs(labels) do
			x, y, z, s = unpack(L)
			draw_bitmap_string("h12", s, x, y, z)
		end

		glPointSize(label_point_size)

		glBegin(GL_POINTS)

		for _, L in pairs(labels) do
			x, y, z, s = unpack(L)
			glVertexd(x, y, z)
		end

		glEnd()

		glPointSize(1)
		glColord(0.0, 0.0, 0.0, 1.0)
	end

	if drawing_thumbnails == true then
		-- These have to be done while we still have the GL
		-- matrices and viewport set up from the 3D drawing.
		local icor, ihor, isag
			= get_indexes_from_mouse()

		local wt = bm.coronal_max_width

		glViewport(w - wt - 10, 0, wt + 10, h)
		glDisable(GL_DEPTH_TEST)

		glMatrixMode(GL_PROJECTION)
		glLoadIdentity()
		glOrtho(1, wt, 1, h, 0, 1)
		glMatrixMode(GL_MODELVIEW)
		glLoadIdentity()

		-- Figure out which section to draw, based on where the mouse is
		-- pointing in 3D.
		glPixelZoom(1.0, -1.0)	-- GL draws images upside down by default.

		-- Draw a white square behind all the images
		glColord(1, 1, 1)

		local x0, y0, x1, y1
			= 1, 1, bm.coronal_max_width, h

		glBegin(GL_QUADS)
		glVertexd(x0, y0)
		glVertexd(x1, y0)
		glVertexd(x1, y1)
		glVertexd(x0, y1)
		glEnd()

		glColord(0, 0, 0)

		local cor_img = bm.coronal_thumbnails[icor]

		h = h - 1

		if cor_img ~= nil then
			glRasterPosd(1, h)
			cor_img:draw_pixels()
		end

		h = h - bm.coronal_max_height - 1

		local sag_img = bm.sagittal_thumbnails[isag]

		if sag_img ~= nil then
			glRasterPosd(1, h)
			sag_img:draw_pixels()
		end

		h = h - bm.sagittal_max_height - 1

		local hor_img = bm.horizontal_thumbnails[ihor]

		if hor_img ~= nil then
			glRasterPosd(1, h)
			hor_img:draw_pixels()
		end

		set_up_3D_viewport_and_matrices()	-- put it back so we can calc mouse coords
	end

	glFlush()
	glutSwapBuffers()
end

-- It's not really zooming but moving the camera toward or away from the
-- object being viewed.

local zoom_to_fit = function()
	camera_distance = sqrt(edges[1] ^ 2 + edges[2] ^ 2 + edges[3] ^ 2) / sin(fovy_deg * pi / 360.0) / 2.0
	camera_pivot = center
end

bm.set_idle_callback(nil)
zoom_to_fit()

-- Run the given Lua file
local run = function(filename)

	local cmd = loadfile(filename)

	if cmd ~= nil then
		cmd()
	else
		warn("Could not run " .. filename)
	end
end

local restart = function()
	run("bminit.lua")
end

local run_user_selected_lua_script = function()
	run(bm.get_filename())
end

local browse_coronal = function()

	local icor, ihor, isag = get_indexes_from_mouse()
	local name = bm.coronal_names[icor]

	if name ~= nil then
		bm.run_process_in_background(browser_path .. " " .. "\"http://brainmaps.org/index.php?dirname=HBP/m.mulatta/RH04/RH04a/&file=HBP/m.mulatta/RH04/RH04a/" .. name .. "/&win=max\"")
	end
end

local browse_horizontal = function()

	local icor, ihor, isag = get_indexes_from_mouse()
	local name = bm.horizontal_names[ihor]

	if name ~= nil then
		bm.run_process_in_background(browser_path .. " " .. "\"http://brainmaps.org/index.php?dirname=HBP/m.mulatta/RH10/RH10a/&file=HBP/m.mulatta/RH10/RH10a/" .. name .. "/&win=max\"")
	end
end

local browse_sagittal = function()

	local icor, ihor, isag = get_indexes_from_mouse()
	local name = bm.sagittal_names[isag]

	if name ~= nil then
		bm.run_process_in_background(browser_path .. " " .. "\"http://brainmaps.org/index.php?dirname=HBP/m.mulatta/RH12/RH12a/&file=HBP/m.mulatta/RH12/RH12a/" .. name .. "/&win=max\"")
	end
end

-- Launch web browsers on brainmaps.org for the three sections specified by
-- the mouse cursor's projection onto the brain surface.
local browse_all_three = function()
	browse_coronal()
	browse_horizontal()
	browse_sagittal()
end

local toggle_transparency = function()
	doing_transparency = not(doing_transparency)
	mesh_color[4] = (doing_transparency and 0.5) or 1.0
end

-- This sets up a temporary idle callback that gradually changes the
-- camera focus to the point in 3D space pointed to by the mouse,
-- while reducing the distance between the camera and that point.
local zoom_in = function()

	local dist, src
		= camera_distance / 4.0, camera_distance
	local x1, y1, z1 = get_mouse_location()

	if max(abs(x1), abs(y1), abs(z1)) < 1e4 then

		local x0, y0, z0 = unpack(camera_pivot)
		local cam_off0 = camera_offset
		local cnt = 0

		bm.set_idle_callback(function()
		        cnt = cnt + 1

			if cnt > 60 then
				bm.set_idle_callback(nil)
			end

			local t = cnt / 60.0
			-- This polynomial u(t) satisfies u(0)=0, u(1)=1,
			-- u'(0)=0, u'(1)=0, so we get a smoother transition than
			-- we would get by using a linear ramp.
			local u = (3.0 - 2.0 * t) * (t ^ 2)
			local v = 1.0 - u

			for i = 1, #camera_offset do
				camera_offset[i] = v * cam_off0[i]
			end

			camera_pivot = {v * x0 + u * x1, v * y0 + u * y1, v * z0 + u * z1}
			camera_distance = v * src + u * dist
		end)
	else
		print("Mouse location is suspiciously large.  Is it off the surface?")
	end
end

local toggle_thumbnails = function()
	drawing_thumbnails = not(drawing_thumbnails)
end

local toggle_position_lock = function()
	locked_position = ((locked_position == nil) and {get_mouse_location()}) or nil
end

-- Parts of this function were borrowed from the OpenGL texgen demo.
local make_stripe_fun = function(x, y, z, a)
	return function()

		local stripe_texture = {}

		for i = 0, 3 do
			for j = 1, 4 do
				stripe_texture[i * 2 + j] = stripe_color[j]
			end
		end
		for i = 4, 127 do
			for j = 1, 3 do
				stripe_texture[i * 4 + j] = mesh_color[j]
			end
			stripe_texture[i * 4 + 4] = 1.0		-- opaque
		end

		gl.glBindTexture(GL_TEXTURE_1D, gl.glGenTextures(1))
		gl.glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT)
		gl.glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
		gl.glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR)

		gl.glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
		gl.gluBuild1DMipmaps(GL_TEXTURE_1D, GL_RGBA, 128, GL_RGBA, GL_FLOAT, stripe_texture)
		gl.glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE)
		gl.glTexGen(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR)
		gl.glTexGen(GL_S, GL_OBJECT_PLANE, x, y, z, a)
		candy_striping = true
	end
end

local cycle_through_draw_styles = (function()

	local draw_mode_switch = {
		[GL_FILL] = GL_LINE,
		[GL_LINE] = GL_POINT,
		[GL_POINT] = GL_FILL,
	}

	return function()
		draw_mode = draw_mode_switch[draw_mode]

		if draw_mode == GL_LINE then
			glDisable(GL_LINE_SMOOTH)
		else
			glEnable(GL_LINE_SMOOTH)
		end

		gl.glPolygonMode(GL_FRONT_AND_BACK, draw_mode)
	end
end)()

local help = function()
	bm.run_process_in_background(pager_path .. " help.txt")
end

local toggle_full_screen =  (function()

	local fullscreen = false
	local last_width, last_height

	return function()
		fullscreen = not(fullscreen)

		if fullscreen == true then
			last_width, last_height = max(1, glutGet(GLUT_WINDOW_WIDTH)), max(1, glutGet(GLUT_WINDOW_HEIGHT))
			glutFullScreen()
		else
			glutReshapeWindow(last_width, last_height)
		end
	end
end)()

local quit = function()
	os.exit(true)
end

local no_stripes = function()
	candy_striping = false
end

-- Global function add_label() for executing labels.txt
add_label = function(x, y, z, text)
	print(("adding label: %3.3f %3.3f %3.3f %s"):format(x, y, z, text))
	table.insert(labels, {x, y, z, text})
end

local begin_command_mode = function()
	kb_cmd_mode = true
end

local load_labels = function()
	print("load_labels")

	local file = io.open("labels.txt")

	if file == nil then
		print("== Result of wget request ==")
		os.execute("wget http://brainmaps.org/labels.txt")
	else
		file:close()
	end

	dofile("labels.txt")
end

local calc_camera_coords = function()

	local theta, phi
		= -y_angle_deg / 180.0 * pi, -x_angle_deg / 180.0 * pi
	local cx, cy, cz = unpack(camera_pivot)

	return cx + camera_distance * cos(phi) * sin(theta), cy + camera_distance * sin(phi), cz + camera_distance * cos(phi) * cos(theta)
end

local add_mouse_label = function()
	local x, y, z = get_mouse_location()
	add_label(x, y, z, "*")
end

---------------
-- Menu
---------------

do
	local menu_items = {
		{ text="Zoom in (i)", func=zoom_in },
		{ text="Zoom to fit (f)", func=zoom_to_fit },
		{ text="Toggle full screen (F)", func=toggle_full_screen },
		{ text="Toggle transparency (T)", func=toggle_transparency },
		{ text="Toggle thumbnails (t)", func=toggle_thumbnails },
		{ text="Toggle position lock (l)", func=toggle_position_lock },
		{ text="Browse coronal (c)", func=browse_coronal },
		{ text="Browse horizontal (h)", func=browse_horizontal },
		{ text="Browse sagittal (s)", func=browse_sagittal },
		{ text="Browse all three (b)", func=browse_all_three },
		{ text="X stripes (x)", func=make_stripe_fun(2, 0, 0, 0) },
		{ text="Y stripes (y)", func=make_stripe_fun(0, 2, 0, 0) },
		{ text="Z stripes (z)", func=make_stripe_fun(0, 0, 2, 0) },
		{ text="Cycle through draw styles (m)", func=cycle_through_draw_styles },
		{ text="No stripes (n)", func=no_stripes },
		{ text="Load labels (L)", func=load_labels },
		{ text="Add label (p)", func=add_mouse_label },
		{ text="Lua prompt (:)", func=begin_command_mode },
		{ text="Run Lua script", func=run_user_selected_lua_script },
		{ text="Help (?)", func=help },
		{ text="Restart (r)", func=restart },
		{ text="Quit (q)", func=quit },
	}

	bm.reset_menu()

	for _, v in pairs(menu_items) do
		bm.add_menu_item(v.text, v.func)
	end
end

on_mouse = function(button, state, xi, yi)
	shift_is_pressed = (glutGetModifiers() & GLUT_ACTIVE_SHIFT) ~= 0
	ctrl_is_pressed  = (glutGetModifiers() & GLUT_ACTIVE_CTRL ) ~= 0

	if state == GLUT_DOWN then
		if button == GLUT_LEFT then
			mouse_xi, mouse_yi = xi, yi
		end
	end
end

on_motion = function(xi, yi)

	if shift_is_pressed == true then
		-- move camera closer in or further out
		camera_distance = camera_distance / exp(0.01 * (yi - mouse_yi))
	elseif ctrl_is_pressed == true then

		local h = max(1, glutGet(GLUT_WINDOW_HEIGHT))
		-- z=0 at near clipping plane (http://www.opengl.org/resources/faq/technical/glu.htm)
		local z = camera_distance / (zfar - znear)

		glPushMatrix()
		glLoadIdentity()

		local pprev = {gluUnProject(mouse_xi, h - mouse_yi - 1, z)}
		local p	= {gluUnProject(xi, h - yi - 1, z)}

		glPopMatrix()

		for i = 1, #camera_offset do
			camera_offset[i] = camera_offset[i] + edges[i] * (p[i] - pprev[i])
		end
	else
		y_angle_deg = y_angle_deg + 0.5 * (xi - mouse_xi)
		x_angle_deg = x_angle_deg - 0.5 * (yi - mouse_yi)
	end

	mouse_xi, mouse_yi = xi, yi

	glutPostRedisplay()
end

on_passive_motion = function(xi, yi)
	mouse_xi, mouse_yi = xi, yi;
	glutPostRedisplay()
end

---------------
-- Key bindings
---------------
local key_bindings = {
	['C'] = function()
			print(("camera: %.3f %.3f %.3f"):format(calc_camera_coords()))
		end,
	['L'] = load_labels,
	['m'] = cycle_through_draw_styles,
	['P'] =	function()
			print(("%4.3f %4.3f %4.3f"):format(get_mouse_location()))
		end,
	['p'] = add_mouse_label,
	['?'] = help,
	['r'] = restart,
	['h'] = browse_horizontal,
	['s'] = browse_sagittal,
	['c'] = browse_coronal,
	['b'] = browse_all_three,
	['f'] = zoom_to_fit,
	['i'] = zoom_in,
	['t'] = toggle_thumbnails,
	['F'] = toggle_full_screen,
	['T'] = toggle_transparency,
	['x'] = make_stripe_fun(2, 0, 0, 0),
	['y'] = make_stripe_fun(0, 2, 0, 0),
	['z'] = make_stripe_fun(0, 0, 2, 0),
	['n'] = no_stripes,
	['l'] = toggle_position_lock,
	['q'] = quit,
	-- Bring up a lua command prompt, for power users
	[':'] = begin_command_mode,
}

on_keyboard = function(key, xi, yi)
	if kb_cmd_mode == true then
		-- If it's Enter, then try to execute the command.
		if key == 13 then

			local loaded_cmd = loadstring(command)

			if loaded_cmd ~= nil then

				local status, result = pcall(loaded_cmd)

				if status ~= false then
					if result ~= nil then
						print(result)
					end
				else
					warn("Lua error. ", result)
				end
			else
				warn("Lua syntax error.")
			end
			km_cmd_mode = 0
			command = ""

		-- If it's backspace or delete, then try to delete the last
		-- character in the command.
		elseif key == 8 or key == 127 then
			command = command:sub(1, -2)

		-- If it's Esc or ctrl-c, then abort the command
		elseif key == 27 or key == 3 then
			kb_cmd_mode = false
			command = ""
		else
			-- Otherwise, add the character to the command.
			command = command .. string.char(key)
		end
	else

		local f = key_bindings[string.char(key)]

		if f ~= nil then
			f(xi, yi)
		end
	end

	glutPostRedisplay()
end