Shaders - Development¶

Shaders add a powerful system of rendering light, the elements of the world, and more.

Overview¶

The Shaders mod makes use of a deferred rendering pipeline.

The gbuffer shaders come first in the pipeline. They render data to textures that will be sent to the composite shaders. Optional composite shaders can be added after the shadow map (shadowcomp), before terrain (prepare) and before water rendering (deferred). The composite shaders then render to textures that will be sent to the final shader.

The final shader renders directly to the screen.

Dimension shaders¶

Shaders can be separated by world dimension by placing them in folder /shaders/world<id>, where id is the world dimension. When the world folder is present, the shaders will be loaded only from there; they ignores the default folder. Creating an empty world folder effectively disables the shaders for that world dimension. Mod world dimensions should also work.

Only .vsh and .fsh files are loaded from the dimension folder.

Example:

• /shaders: default shaders

• /shaders/world-1: nether shaders

• /shaders/world1: end shaders

Dimension folders are also scanned for options. The options in dimension folders may be given different names to avoid conflict with default values.

The #include directive found in .vsh and .fsh files is replaced with the contents of the included file:

#include "const.inc"

#include "/world-55/lib.inc"

Included files may include other files.

To avoid code duplication on nested inclusions, the following can be used:

// File A

#ifndef INCLUDE_A
#define INCLUDE_A
...
#endif

Files¶

All shader files are placed in the folder shaders/ of the shader pack. The shader source files use the name of the program in which they are to be used with extension depending on their type.

Geometry shaders need either OpenGL 3.2 with layout qualifiers or the extension GL_ARB_geometry_shader4 (GL_EXT_geometry_shader4) with configuration "maxVerticesOut".

Compute shaders¶

A list of compute shaders can be attached to every program except gbuffers programs. They are named like the program with optional suffix, for example "composite.csh", "composite_a.csh" ... "composite_z.csh".

Compute shaders run before the program and can read from all buffers using texture samplers. They can read and write to colortex0-5 and shadowcolor0-1 buffers as images using the aliases colorimg0-5 and shadowcolorimg0-1, for example: layout (rgba8) uniform image2D colorimg0;.

Compute shaders need at least "#version 430" and local size definition, for example: layout (local_size_x = 16, local_size_y = 16) in;. Work groups are defined either fixed via const ivec3 workGroups = ivec3(50, 30, 1); or relative to render size via const vec2 workGroupsRender = vec2(0.5f, 0.5f);. The default configuration is const vec2 workGroupsRender = vec2(1.0f, 1.0f);, which executes the compute shader once per pixel.

Image access¶

All programs can read and write to colorimg0-5 and shadowcolorimg0-1 using imageLoad() and imageStore().

Attributes¶

Block render layers¶

See Block Render Layers.