setscreen ("offscreenonly")

type points :
    record
        x, y : real
    end record

var p : array 0 .. 9 of points
var newp : array 0 .. 100 of points
var mx, my, mb : int
var key : array char of boolean

for i : 0 .. upper (p)
    loop
        Mouse.Where (mx, my, mb)
        var valid := false
        if mb = 1 then
            loop
                Mouse.Where (mx, my, mb)
                if mb = 0 then
                    valid := true
                    p (i).x := mx
                    p (i).y := my
                    Draw.FillOval (mx, my, 3, 3, black)
                    View.Update
                    exit
                end if
            end loop
        end if
        if valid = true then
            exit
        end if
    end loop
end for

proc bezier_calc (pts : array 0 .. * of points, state, n : real)
    var pt : array 0 .. upper (pts) - 1 of points
    if upper (pts) > 1 then
        for i : 0 .. upper (pt)
            pt (i).x := (pts (i + 1).x - pts (i).x) * state + pts (i).x
            pt (i).y := (pts (i + 1).y - pts (i).y) * state + pts (i).y
            if i > 0 then
                Draw.Line (round (pt (i - 1).x), round (pt (i - 1).y), round (pt (i).x), round (pt (i).y), RGB.AddColour (1 - n, 0, n))
            end if
        end for
        bezier_calc (pt, state, n - 1 / upper (p))
    elsif upper (pts) = 1 then
        newp (round (state * 100)).x := (pts (1).x - pts (0).x) * state + pts (0).x
        newp (round (state * 100)).y := (pts (1).y - pts (0).y) * state + pts (0).y
        if state > 0.01 then
            for i : 1 .. round (state * 100)
                Draw.ThickLine (round (newp (i - 1).x), round (newp (i - 1).y), round (newp (i).x), round (newp (i).y), 3, brightred)
            end for
        end if
    end if
end bezier_calc

var num : int := 0
loop
    cls
    Input.KeyDown (key)
    if key (KEY_LEFT_ARROW) and num > 0 then
        num -= 1
    elsif key (KEY_RIGHT_ARROW) and num < 100 then
        num += 1
    end if
    for j : 0 .. upper (p) - 1
        Draw.Line (round (p (j).x), round (p (j).y), round (p (j + 1).x), round (p (j + 1).y), grey)
    end for
    bezier_calc (p, num / 100, 1)
    View.Update
end loop

%import Stuff
View.Set ("graphics:max;max, offscreenonly")

var X, Y : array 0 .. 100 of int
var mdx, mdy : array 0 .. 9 of real
var num : int := 0

fcn rv (a, b, r : real) : real
    result (b - a) * r + a
end rv

proc DrawLines (x, y : array 0 .. * of real, thicknes : int, clr : int, intesity : real)
    for a : 0 .. upper (x) - 1
        Draw.ThickLine (x (a) div 1, y (a) div 1, x (a + 1) div 1, y (a + 1) div 1, thicknes, clr)
    end for
end DrawLines

proc CalcCurveDot (x, y : array 0 .. * of real, r : real)
    var lx, ly : flexible array 0 .. 0 of real
    for a : 0 .. upper (x) - 1
        new lx, a
        new ly, a
        lx (a) := rv (x (a), x (a + 1), r)
        ly (a) := rv (y (a), y (a + 1), r)
    end for
    DrawLines (lx, ly, 1, 12, 1 - (upper (lx) / upper (mdx)))
    if upper (lx) = 1 then
        var dx, dy, id : int := round (r * 100)
        dx := rv (lx (0), lx (1), r) div 1
        dy := rv (ly (0), ly (1), r) div 1
        X (id) := dx
        Y (id) := dy
    else
        CalcCurveDot (lx, ly, r)
    end if
end CalcCurveDot


var mx, my, bnum, freeze : int := 0
loop
    Mouse.Where (mx, my, bnum)
    freeze -= 1
    if bnum > 0 and freeze <= 0 then
        mdx (num) := mx
        mdy (num) := my
        Draw.FillOval (mdx (num) div 1, mdy (num) div 1, 3, 3, 255)
        View.Update
        num += 1
        if num > upper (mdx) then
            exit
        else
            freeze := 5
        end if
    end if
    delay (20)
end loop
/*
 for a : 0 .. upper (mdx)
 mdx (a) := Rand.Int (0, maxx)
 mdy (a) := Rand.Int (0, maxy)
 end for
 */

var seq : int := 2
var keys : array char of boolean
CalcCurveDot (mdx, mdy, 0.00)
CalcCurveDot (mdx, mdy, 0.01)
CalcCurveDot (mdx, mdy, 0.02)
loop
    Input.KeyDown (keys)
    if keys (KEY_RIGHT_ARROW) or keys ('d') then
        seq += 1
        if seq > 100 then
            seq := 100
        end if
    elsif keys (KEY_LEFT_ARROW) or keys ('a') then
        seq -= 1
        if seq < 0 then
            seq := 0
        end if
    end if
    CalcCurveDot (mdx, mdy, seq / 100)
    DrawLines (mdx, mdy, 1, grey, 0.8)
    if seq > 0 then
        DrawLines (mdx, mdy, 1, grey, 0.8)
    end if
    if seq >= 1 then
        for b : 0 .. seq - 1
            Draw.ThickLine (X (b), Y (b), X (b + 1), Y (b + 1), 3, 48)
        end for
    end if
    Draw.FillOval (X (seq), Y (seq), 2, 2, 255)
    View.Update
    delay (20)
    cls
end loop