// demonstrates how Lobster's event state can help program common operations without having to store state yourself

import vec

import color

import gl

fatal(gl.window("event animation and mouse drag test", 1024, 1024))

let lines = []

while gl.frame():

if gl.button("escape") == 1: return

gl.clear(color_black)

gl.color(color_white)

// allow user to drag a line, and store it when complete

// note how we can track a drag operation conveniently thanks to gl.last_pos

let start = float(gl.last_pos("mouse1", true))

let cur = float(gl.mouse_pos(0))

if magnitude(start - cur) > 1.0: // a click is not a drag

let down, up = gl.button("mouse1")

if down >= 1: // show feedback

gl.line(start, cur, 1.0)

if up == 1: // store line

lines.push([start, float(gl.last_pos("mouse1", false))])

// note how we use the mouse up position, which may be != cur

// draw previous lines

gl.color(color_light_grey)

for(lines) l:

gl.line(l[0], l[1], 1.0)

// just for demonstration purposes, gl.last_time makes it easy to animate clicks etc.

// we show little animated circles on each mouse down or up

for(2) down:

gl.color(if down: color_green else: color_blue)

let clicktime = gl.time() - gl.last_time("mouse1", down)

if clicktime < 1.0:

gl.translate gl.last_pos("mouse1", down):

gl.line_mode 1:

gl.circle(clicktime * 20.0, 10)