problems with making very simple drawing love app

[alex_]

Hi again!

So I got the idea of trying to create a very simple drawing program where you can left click anywhere on the love window and draw a point there.

So I'm using the love.mousepressed and love.mousereleased functions to get the mouse position and draw a point there, but the point doesn't stay. As
soon as the mouse button is released the point disappears. I'm not sure what to do to make the point stay. Here is what I have:

function love.load()
love.graphics.setColor(255,255,255)
love.graphics.setPointSize(10)
end

function love.update(dt)
end

function love.draw()
end

function love.mousepressed()
mouseX=love.mouse.getX()
mouseY=love.mouse.getY()
end

function love.mousereleased()
love.graphics.point(mouseX,mouseY)
end

[Geti]

you aren't saving the points anywhere. at absolute least you'd want to have it so on mousereleased you do a table.insert(sometable, {MouseX, MouseY}), and then draw with a for loop.
so :

Code: Select all

function love.load()
love.graphics.setColor(255,255,255)
love.graphics.setPointSize(10)
points = {}
end

function love.update(dt)
 --nothing
end

function love.draw()
for k,v in ipairs(points) do
 love.graphics.point(v[1],v[2])
end
end

function love.mousepressed()
mouseX=love.mouse.getX()
mouseY=love.mouse.getY()
end

function love.mousereleased()
table.insert(points, {mouseX,mouseY})
end

you could have a timer function to remove points over time, or fade their transparency or something, but that's for you to implement. you shouldn't be using drawing functions (love.graphics) anywhere but in love.draw really..

[alex_]

Thanks for your post.

Because of it, I read a short tutorial on lua tables to try and understand your solution to my problem, and I figured out how to create a simple undo function for my drawing app by using table.remove()

I also changed the program to draw 1 by 1 pixel sized rectangles, so that the program would be more like an actual pixel art drawing app. (as opposed to using the point function which draws circular points)

Again, thanks for the help!

[Geti]

no worries, pleased to help.

[alex_]

Well, if you could help with one other thing...

How could I make the program so that it would let the user draw freely instead of pixel by pixel? I thought of having a loop going in the love.mousepressed function but I'm not exactly sure how to implement it, or if that's even the way to do it.

[TechnoCat]

try using something like

Code: Select all

if love.mouse.isDown("lb") then
//draw pixel at x,y
end

in your love.update(dt) callback.

[alex_]

1st edit: on second thought, maybe I should just try it out!

2nd edit: btw I did it, was actually quite easy!