Coloured Lights - Minecraft Iris shader library

Coloured Lights is a library to easily add coloured light blocks to your Minecraft Iris shader. SSBOs are a required feature. Can also be used standalone.

License

All the code in this repository is licensed under GNU GPLv3.

Usage

Using standalone

Download a ZIP file of this repository on GitHub, then extract the ZIP file over to your shaderpacks directory. Everything should work out of the box.

Including in your own shaderpack

All shaders using the library must be using GLSL 430 or above. Copy the lib folder in the shaders directory to your own shaders directory. In your gbuffers_terrain vertex shader, add the following lines at the top, below your #version statement:

#define VERTEX

#include /lib/cl/common.glsl

Your vertex shader must be using the compatibility profile of GLSL. In your main function, add the following line:

lightCheck(at_midBlock, mc_Entity);  

at_midBlock and mc_Entity being input attributes.

In every fragment shader where you will want to apply the coloured lights, add the following line below your #version statement:

#include /lib/cl/common.glsl  

Your fragment shader can use the core profile of modern GLSL versions. In the main function, add the following lines:

vec4 startLight = texture(lightmap, lightMapCoord);
colortex0 = applyColouredLight(colortex0, startLight, worldPos, localChunkPos);

colortex0 is your output colour. It's important that you don't multiply your output colour with the lightmap texture value, the applyColouredLight method will do that for you.

worldPos is a vec3 and localChunkPos is a flat ivec3, both passed from the vertex shader, and can be calculated like this:

worldPos = modelToWorldSpace(gl_Vertex.xyz);
localChunkPos = blockPosToChunkPos(blockPosToLocalPos(worldPosToBlockPos(worldPos, at_midBlock)));

at_midBlock being an input attribute.

Copy the begin.csh file in the shaders directory over to your shaders directory.

The library contains some default block light colours, but you'll have to include the block IDs. Merge the block.properties file in the shaders directory with your own block.properties file.

You'll also have to correctly set up your SSBOs. To do this, merge the shaders.properties file in the shaders directory with your own shaders.properties file. This will also include a nice option screen for the coloured lights. Copy the lang directory over to your shaders directory for English translation keys of the option screen.

Adding/changing the coloured light blocks

Open the /lib/cl/lights.glsl file in your shaders directory. This should contain the colouredLights array, which contains all the coloured light blocks. The syntax is as follows:

const ColouredLight[] colouredLights = ColouredLight[<array size>](
    ColouredLight(<block ID>, <light level>, <light colour>, <natural>),
    ...
);

• <array size> is the size of the colouredLights array.
• <block ID> is an unsigned integer, the ID of the coloured light block as defined in block.properties.
• <light level> is the light level the block gives (can be a float, but is recommended to be an integer).
• <light colour> is a vec3, the colour the block gives off.
• <natural> is a boolean. Only set it to false if the block in question doesn't give light in vanilla.

Known issues

• Light colours render through blocks due to occlusion culling issues.
• Light colours can glitch out in the Nether (and possibly End).