-- Define the code to calculate where the camera is, in world coordinates.
local eye = function(frame)
-- just rotate around the center of the scene on the XZ plane
- local center = {x = 0, y = 1, z = 0}
+ local center = vec_new(0, 1, 0)
local distance = 4
local start = math.pi
local t = start + 2 * math.pi * frame / frames
- local v = {
- x = math.cos(t),
- y = 0,
- z = math.sin(t),
- }
+ local v = vec_new(math.cos(t), 0, math.sin(t))
return vec_add(vec_scale(v, distance), center)
end
-- Define the code to calculate where the focal point of the scene is.
local look = function(frame)
- return {x = 2, y = 1, z = 2} -- keep focused on the buddha
+ -- keep the camera focused on the buddha
+ return vec_new(2, 1, 2)
end
-- Define the actual objects of the scene that will be rendered, in the
local fmt = string.format
local write = function(...) io.write(fmt(...)) end
+function vec_new(x, y, z)
+ return {x = x, y = y, z = z}
+end
+
function vec_add(a, b)
- return {x = a.x + b.x, y = a.y + b.y, z = a.z + b.z}
+ return vec_new(a.x + b.x, a.y + b.y, a.z + b.z)
end
function vec_scale(v, s)
- return {x = v.x * s, y = v.y * s, z = v.z * s}
+ return vec_new(v.x * s, v.y * s, v.z * s)
end
function render(i)