LibGDX and Getting Pixels From Sprite

Newbie & Debugging Questions
#1

I want to implement the ability for people to change the way players characters look, and by that I mean that I want to give the players the ability to change the colors of their given hero. Which is an png. The only problem is that I need the image as a sprite to make use of LibGDX’s flip and scale functions to the nearest pixel, so I retain that awesome pixel-y look. No methods, not even Pixmap, are giving me what I need. I thought about taking a BufferedImage, saving the data, writing the data as a new player png (Which I may have to do so I dont keep loading in the same stupid thing and messing up) and then just assigning that to the player. But what if the player makes 10’s or hundreds of characters? I would have 10’s of hundreds of .pngs of different heroes my player would probably not use. I also noticed that when Notch made Minicraft for LD22 a long time ago, he performed exactly what I would like to do!

My question is, with LibGDX’s given library, is there a way I could copy Notch’s Minicraft attempt at saving the images as grayscale, and just applying colors at runtime?

#2

Not really.

Not with libgdx… At least performance wise. The way he did it is he took 4 gray colors (0, 85, 170, 255) and when rendering he would assign each of these colors a color he wanted with code.

Have you watched vanzeben’s tutorials? I’m pretty sure he explains just that method.

#3

Are you using a SpriteBatch to render your characters? If you simply to batch.setColor(color) the texture you render after that will be tinted in the color you specify. Thats what I use for these kinds of customizations, works like a charm.

One trick (that I never used, but it should work) is to render your characters to the screen (without swapping the buffers so nothing is shown) and then copying the rendered character to a Texture e.g. using the ScreenUtils methods.

#4

You can get the pixels from the texture, unless I’m thinking a pixmap. You can then store them in a 2D array but like you I have no idea if you manipulate them from there.

Just have all your images shades of grey, then apply a tint.

#5

@grunt and gibbo

You don’t seem to understand what he wants.

He doesn’t want tinting. He wants to replace certain gray colors with custom colors in code.

#6

I understand what he wants, I told him you can get the pixels of a texture but if there is a way to manipulate them with libgdx, no idea.

I then suggested an alternative, is all.

#7

Could you do something along the lines of:
• Load an image as a BufferedImage (RGBA)
• Loop through its pixel data
• Each Integer value that has an RGBA can be replaced with an RGBA of the custom colour.
• Store this image as the player sprite.

Scratch that, googled and found out its a bad idea.
Source: http://www.java-gaming.org/index.php?topic=29243.0

That said, could you render the sprites in layers? Tint only the bits that need to be tinted?

#8

[quote=“trollwarrior1,post:5,topic:48065”]
Where precisely do you read that he “does not want tinting”? I’m curious.

I dont see how my solution does not give him what he wants. You can flip and scale a tinted texture to your heart’s content.

#9

[quote=“Grunnt,post:8,topic:48065”]

It’s because he wants to do it like notch did it in minicraft. And notch didn’t tint the textures in minicraft :wink:

#10

Use a fragment shader.

#11

[quote=“matheus23,post:9,topic:48065”]
In case the OP wants to know how Notch did it, here’s the code:

Its in Java2D, and its also 100% officially silly to try to do this in OpenGL and LibGDX. It is extremely slow, error-prone, terribly overcomplicated and pretty much worst practice (unless you enjoy making life difficult for yourself). Much better do someting like:

batch.setColor(bodyColor);
batch.draw(bodyTexture, ...
batch.setColor(pantsColor);
batch.draw(pantsTexture, ...
...

Easy peasy.

#12

Thanks Grunnt, but I wasnt saying I wanted to use Java2D with my current LibGDX setup, I was simply asking if there was a possible way to get it going. I would use a tint, but the tint does not give me the same look I was going for. Tint gives me some crazy dark colors, and I can only go so far with some things.

I’ll take a look at it again, and If I run into more trouble, I’ll post my code after work.