-- MoonCCD example: hello.lua
local ccd = require("moonccd")

-- Support function for box objects:
local function support(obj, dir)
    -- Assume obj is a user defined table containing info about the object,
    -- in this case a box: obj = { pos, quat, x, y, z } where pos is the
    -- position, quat is the rotation, and x, y, z are the dimensions.
    -- Apply the rotation on direction vector:
    local qinv = ccd.qinvert(obj.quat)
    dir = ccd.vrotate(dir, qinv)
    -- Compute the support point in the specified direction:
    local v = {0.5 * ccd.sign(dir[1]) * obj.x, 0.5 * ccd.sign(dir[2]) * obj.y, 0.5 * ccd.sign(dir[3]) * obj.z}
    -- Transform support point according to the rotation of the object and return it
    v = ccd.vrotate(v, obj.quat)
    v = ccd.vadd(v, obj.pos)
    return v
end

-- Create two box objects:
local box1 = {
    pos = {-5, 0, 0},
    quat = {1, 0, 0, 0},
    x = 1,
    y = 2,
    z = 1,
}
local box2 = {
    pos = {0, 0, 0},
    quat = {1, 0, 0, 0},
    x = 2,
    y = 1,
    z = 2,
}

-- Create and initialize the ccd parameters:
local ccdpar = ccd.new({
    support1 = support, -- support function for first object
    support2 = support, -- support function for second object
    max_iterations = 100, -- maximum number of iterations
})

for i = 0, 99 do
    local intersect = ccd.gjk_intersect(ccdpar, box1, box2)
    -- now intersect is true if the two boxes intersect, false otherwise
    -- print(i, intersect, box1.pos[1], box2.pos[1])
    if i < 35 or i > 65 then
        assert(not intersect)
    elseif i ~= 35 and i ~= 65 then
        assert(intersect)
    end
    -- move first box along the x axis:
    box1.pos[1] = box1.pos[1] + 0.1
end