Love Remove Image command Request

[weilies]

i have drawn 3 images, code below

Code: Select all

function love.draw()

		
	-- draw image
	love.graphics.draw(arrow, 100, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
	love.graphics.draw(arrow, 200, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
	love.graphics.draw(arrow, 300, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)

end

input handler

Code: Select all

-- key press 'c' to clear my image
love.graphics.clear ( )

but i realized that next second it will redraw 3 images due to the draw always callback
My question is how can i click on "c" and only the second image above is remove and other remain unchange?
What is the proper remove-image command to use? love.graphics.clear ( ) doesnt look right for me coz it will always clear all my object on screen


Thanks again for all the help!

[bartbes]

Instead of removing it, you need to stop drawing it, so you probably want an if in your love.draw.

[weilies]

Instead of removing it, you need to stop drawing it, so you probably want an if in your love.draw.

any sample? isn't that better for every image object created, will be assign to a variable

Eg. logic

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myObjRef[1] =  love.graphics.draw(image, imgx, imgy)

love.graphics.stopDraw(myObjRef[1] )

Let say if i am creating a Space Invader game, how hard for me to create a "stop draw when shoot collide" logic
or any actual working sample out there for love engine?

[kikito]

You have not understood the fundamentals yet. Please read the next two points carefully:

• love.draw is a function that gets called once per frame
• Before calling it, LÖVE erases the screen completely

What bartbes says is that the only thing you have to do in order to 'stop drawing' your images is to literally stop calling love.graphics.draw inside love.draw. You need to do the equivalent to this:

Code: Select all

 function love.draw()
  if condition_for_drawing_arrow then   
     love.graphics.draw(arrow, 100, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
     love.graphics.draw(arrow, 200, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
     love.graphics.draw(arrow, 300, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
  end
end

On that sample, condition_for_drawing_arrow is an expression that you have to build. A good way to start would be to create some global variables, update them on love.update, and use them on love.draw for conditionally drawing stuff.

[weilies]

hi kikito,

Thanks for the reply and yes, i am still new bird who in love

i jz figure out this yday night

* love.draw is a function that gets called once per frame

i jz know this after reading this post

* Before calling it, L?VE erases the screen completely

regarding the function below

Code: Select all

    function love.draw()
      if condition_for_drawing_arrow then   
         love.graphics.draw(arrow, 100, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
         love.graphics.draw(arrow, 200, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
         love.graphics.draw(arrow, 300, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
      end
    end

i notice this is the way to draw/remove after i know the role below (and reason i open this thread is to ask for any friendly alternative solution)

* love.draw is a function that gets called once per frame

i actually come from other game programming background,
Question for the creator of love (no offence)
since we are using command below to create an object on screen

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	love.graphics.draw(arrow, 100, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
isn't that better to store the object to a variable (as an object), so that later can use object.scaleX, object.getPostX, object.RemoveMe
	fish = love.graphics.draw(fish_sprite, 100, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)
	fish_food = love.graphics.draw(food_sprite, 100, 200, math.rad(arrow_rotate_angle), 1, 1, 75, 200)

then when fish fish collide with fish_food

we jz write fish_food.RemoveMe

instead of saying, "if fishfood_not_yet_eaten" logic
i mean, if my idea doesn't work in love, i will follow kikito's approach

[nevon]

i mean, if my idea doesn't work in love, i will follow kikito's approach

You can most certainly do that. One common approach is using object orientation and give each object its own draw method.

[vrld]

You don't seem to understand correctly.
love.graphics.draw does exactly what the name suggests: It draw to the screen. It does not put an object there. It just draws.
If you don't want something on the screen, you must not draw it.

The other game engine you used probably used a some sort of scene management, where you actually have objects that get drawn for you. Love is more low-level than this.

[zac352]

o_O Why is it taking so long for you to understand?
Love works per frame.
If something is supposed to appear on screen, you draw it. If it isn't, you don't draw it....

[bartbes]

I'd like to note that you should totally ignore zac352.

[zac352]

I'd like to note that you should totally ignore zac352.

That's probably true.