The Synchronous Blog

A blog about reactive programming languages.

Some graphical examples

with 3 comments

The following are two graphical applications written in LuaGravity with respective videos and source codes.

The first example shows some flying rectangles whose size and speed increase as they get closer to the screen base.

Follows the source code:

for i=1, 15
    local r = screen:add(
        Rect {
            _fill = {r=255,g=200,b=100},
            x = screen.dx()/2 + S(math.random(-15,15)),

    local v = 1 + r.y^1.3/(screen.y()+screen.dy())
    r.y = S(math.random(1,15)*v)

    local dim = 1 + r.y/5
    r.dx = dim
    r.dy = dim

The second example shows the mouse cursor surrounded by orbiting rectangles.
The orbit radius may be changed explicitly.
It’s based on an example found in the FrTime distribution.

Follows the source code:

local secs = S(1)
local sin  = L(math.sin)
local cos  = L(math.cos)
local C    = 2/3 * math.pi

radius = 50
size   = 20

for i=1, 3
        Rect {
            _fill = {r=255,g=0,b=0},
            x  = (mouse.x + radius * sin(secs+C*i)) - size/2,
            dx = size,
                y  = (mouse.y + radius * cos(secs+C*i)) - size/2,
                dy = size,

Written by francisco

August 21, 2008 at 4:54 pm

Posted in Examples

Tagged with , ,

3 Responses

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  1. Parece até fácil fazer, do jeito que vc esta escrevendo..:)


    Anxious Girl

    September 10, 2008 at 2:34 pm

  2. […] language. LuaGravity provides constructs based on them, which I consider even more useful than the functional […]

  3. […] all made implicitly. Much less verbosity. The reactive variables of LuaGravity (shown here and here) override Lua’s default behavior for […]

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