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Asked By
pronax
Hi, I want my program to generate random numbers and draw a graph (chart) on them, but I ran into such a problem that when redrawing a frame through the update() method, my old line is deleted.
How can I draw new lines without deleting the old ones?
My current code:
var pre_y = 0
var y = 0
var pre_x = 0
var x = 0
func _on_Timer_timeout():
rng.randomize()
y = int(rng.randi_range(-500,500))
x+=20
update()
func _draw():
draw_line(Vector2(pre_x,-pre_y), Vector2(x, -y/20), Color(255, 0, 0), 0)
pre_y = y/20
pre_x = x
You could store each vector pair in a new array and store them all in an other array. Then, call the draw_line method by looping throught this array.
Here an exemple:
var lines_array= [
[Vector2(0, 0), Vector2(50, 0)], #array for the line 1
[Vector2(0, 50), Vector2(50, 50)], #array for the line 2
[Vector2(0, 100), Vector2(50, 100)], #array for the line 3
] #main array
func _draw():
for line in lines_array:
draw_line(line[0], line[1], Color(255, 0, 0), 0)
In your case, you have to add the new vectors pair in the main array from your update method.
Thanks, but how can I do this dynamically?
So that every second a new line is drawn (up or down, depending on the value) and the player sees a change in the graph in real time.
