Going forward and backward with a caracter

[Solitaire]

Hello, muchachos;

I've got a problem. I'm xant to make a 2D scrolling game, but I can't figure out how to change the sprite when going in an opposite direction. Here's the code :

Code: Select all

require("AnAL")


function love.keypressed(key)
	if (key == "right") then
		anim:seek(1)
	end
end

function love.keypressed(key)
	if (key == "left") then
		anim:seek(14)
	end
end

function love.load()
	img = love.graphics.newImage("perso.png")
	bg = love.graphics.newImage("bg.png")
	anim = newAnimation(img, 170, 400, 0.1, 13)
	x = 0
end

function love.update(dt)
	if love.keyboard.isDown ("right") then
		anim:update(dt)
		x = x + 2
	
	elseif love.keyboard.isDown("left") then
		anim:update(dt)
		x = x - 2
	end
	
end

function love.draw()
	love.graphics.draw(bg)
	anim:draw(x, 100)
end

I've got a sprite sheet named "perso" containing 13 sprites of the character moving right, and 13 sprites of him moving left, so how do I do to switch sprites when changing the pressed button ?

[raidho36]

You can have another sprite flipped horizontally. Or you can flip it in such way during rendering.

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love.graphics.draw ( sprite, x, y, -1, 1 ) --latter two are X and Y scale, negative X scale does horizontal flipping. Play around with it to see how it works

[Kingdaro]

The fourth parameter for love.graphics.draw is rotation, so it'd be:

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love.graphics.draw ( sprite, x, y, 0, -1, 1 )

[Selenaut]

I don't think rotation would help, as that would make the sprite appear upside-down. Solitaire wants the image to be flipped horizontally.

[raidho36]

That's what he said. I simply forgot about third argument being rotation.

[Kingdaro]

Yeah, why is the third argument rotation? That would imply that more people use just rotation than they use scaling and offsets, and I think this is far from the truth...

[mickeyjm]

Yeah, why is the third argument rotation? That would imply that more people use just rotation than they use scaling and offsets, and I think this is far from the truth...

I often use rotation and seldom use scaling actually

[Jasoco]

Yeah. I'm more likely to scale using love.graphics.scale. But when I do scale from within the image I just set the rotation to 0. Easy peasy.

[raidho36]

According to what slime said, arguments order in drawing function is exactly the order specified transformations are applied before rendering. In following example, both snippets yield same result:

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love.graphics.draw ( sprite, x, y, r, sx, sy, ox, oy, kx, ky )

--====--

love.graphics.translate ( x, y )
love.graphics.rotate ( r )
love.graphics.scale ( sx, sy )
love.graphics.translate ( ox, oy )
love.graphics.shear ( kx, ky )
love.graphics.draw ( sprite ) --implying you can omit X and Y

If you don't certain arguments, you can just pass nil for them.

[Solitaire]

Well, now it's helpful for a rotation and stuff, but now, if I want it to jump, i'll have to "hide" the current sprite and replace it by another one. How do I achieve this ?