Shaders

Various Godot shader info

Also check the shader section of this manual!

Knowhow

Official reference

Tiling and offset

This can be easily archived:

uniform sampler2D texture_albedo:
        source_color,
        filter_linear_mipmap,
        repeat_disable; // repeat_enable for looping texture

uniform vec2 tiling = vec2(1.0, 1.0);
uniform vec2 offset;

void vertex() {
    UV = UV * tiling + offset * TIME; // Time for animated, remove for static
}

Masking

Simply multiply the alpha with another texture (one channel, for example red):

ALPHA *= texture(mask, UV).r;   // take red intensity as mask
ALPHA *= UV.r;                  // represents a horizontal gradient
ALPHA *= UV.g;                  // represents a vertical gradient

Distortion

Simply add a displacement texture to the UV

float noise_val = texture(noise_texture, UV).r;
vec2 distortion_uv = UV + noise_tex * distortion_intensity;

Particle shading

Particle age can be used in the shader via

varying float lifetime;

void vertex() {
    lifetime = INSTANCE_CUSTOM.y;
}

A fade in and out effect can be created via

varying float life_time; // the actual age
varying float life_alpha; // the age faded in and out

void vertex() {
    life_time = INSTANCE_CUSTOM.y;
    if (life_time<fade_in){
        life_alpha = 1.0 - abs( lifetime - fade_in ) / fade_in; 
    }
    else
    {
        life_alpha = 1.0 - ( lifetime - fade_in ) / (1.0 - fade_in);    
    }
}

Remap between two values (not pretty)

final_color.a = clamp((clamp(tex.a * life_alpha, .5-cutoff_range, .5+cutoff_range) - .5 + cutoff_range) / cutoff_range, 0.0, 1.0);

Time

Time is a global built-in. (No idea why those are located in the fog shader ref)

It repeats after every 3,600 seconds (which can be changed with the rollover setting). It's affected by time_scale but not by pausing.

COLOR.a = smoothstep(end_time, start_time, TIME);

Screen Space Render

from Reddit

There is simply no option for implementing a full screen shader or a shader that utilizes screen-space without doing some janky nonsense to make it work

You can follow this documentation page to setup a quad or just a triangle mesh and apply a screen space shader.

There's also a new CompositorEffect API is available in Godot 4.3 for screen-space shaders. You'll be able to hook to the different rendering passes Godot does.

If I want to apply a post-processing effect to a group of objects without applying it to other objects

If it's in 2D you can use a CanvasGroup In 3D you still need to use a SubViewport as far as I can see.

let's say I want to always render a player's gun in front of their view model.

You can use a shader for that no need to use viewports. More info here (Twitter) and here (Youtube).

Public available custom shaders

GodotShaders.com: Great resource for shaders!

Shader	Notes
Terrain Layered Shader	create large terrains on premade meshes using tiling textures. Youtube Tutorial
Additive Linear Volume	Simple method for volumetric lighting effects
Standard Lighting Shader Include	to simplify writing custom light functions.
Parallax Mapping	For portal effects

Addons

Acerola Compute by Acerola. Abstraction Layer for Godot shaders.

Tutorials / Knowhow

AcerolaFX by Acerola:

Simplifying Shaders by Acerola. Github Project