Pixel Mapping Shader for Gamemaker

Have you ever wanted to just change a couple of pixels on a character but didnt want to then make the change in every single frame of animation? With some preperation, this asset allows you to have you character fully editable at runtime. The idea is that the sprite is now rendered similarly to how 3d models are with UV maps and textures. 

This shader is largely inspired by Jacob @aarthificial. He has a made the same thing in Unity with a very well explained video that you can find here:

The process to use this is the following. 

1. You take the character you have and create an unwraped texture of that character. Have to think a bit 3 dimensionally when doing this since this texture will have everything you can see on the character from any angle.

2. You the take that texture and color code it, meaning you assign a unique color to every single pixel of the character. I have included a handy image with unique palletes that you can use.

3. Then you go to the sprite sheet of your character and replace every single pixel of every frame of the character according to the colors you chose in the previous step.

4. You run the texture and sprite sheet you have created through my exporter. It will give you a version of the spritesheet where each pixels RED and GREEN values are the x/y coordinates of the appropriate pixel on the texture image.

5. You are done. you can now use the shader to draw your character. You only need to provide the texture you want to use and it will be applied. That texture can be changed however at ANY moment, you can even make it so the player can draw on it if you want. You can use this to show the player getting more and more wet,dirty or bloody. You can very easily add or remove accessories from your character. Youve never seen pixelart so dynamic!

Limitations

- The texture image size needs to be a power of 2 and have the "seperate texture page" flag checked

- The texture image can be a maximum of 256 x 256 pixels since the RGB values dont go higher. The blue value can be used though to increase that limit. Will add this in the future if theres demand.