PS1/PSX PostProcessing

Usage:

  1.  Set up the scene as follows:
    SubViewportContainer -> SubViewport -> Spatial
    where Spatial is your 3D scene.
  2. In the SubViewportContainer  add a new ShaderMaterial
  3. In the ShaderMaterial add a new Shader
  4. Copy the script below into the Shader-Editor.

Documentation

  • enabled: Easy option to switch off the shader.
  • dither_size: Defines the pixel size that is used for dithering
  • dithering: Use the dithering pattern.
  • colors: Amount of colors that will be used.

Hint

This shader is written for Godot 4.

 

Shader code
shader_type canvas_item;

render_mode unshaded;

#define MAXCOLORS 16

uniform bool enabled = true;
uniform bool dithering = true;
uniform int colors : hint_range(1, MAXCOLORS) = 12;
uniform int dither_size: hint_range(1, 8) = 1;

float dithering_pattern(ivec2 fragcoord) {
	const float pattern[] = {
		0.00, 0.50, 0.10, 0.65, 
		0.75, 0.25, 0.90, 0.35, 
		0.20, 0.70, 0.05, 0.50, 
		0.95, 0.40, 0.80, 0.30
	};
	
	int x = fragcoord.x % 4;
	int y = fragcoord.y % 4;
	
	return pattern[y * 4 + x];
}

float reduce_color(float raw, float dither, int depth) {
	float div = 1.0 / float(depth);
	float val = 0.0;
	int i = 0;

	while (i <= MAXCOLORS)
	{
		if (raw > div * (float(i + 1))) {
			i = i + 1;
			continue;
		}

		if (raw * float(depth) - float(i) <= dither * 0.999)
		{
			val = div * float(i);
		} 
		else
		{
			val = div * float(i + 1);
		}
		return val;

		i = i+1;
	}

	return val;
}

void fragment() {
	vec4 raw = texture(TEXTURE, SCREEN_UV);
	ivec2 uv = ivec2(FRAGCOORD.xy / float(dither_size));

	if (enabled == true){
		float dithering_value = 1.0;
		if (dithering)
		{
			dithering_value = dithering_pattern(uv);
		}
		
		COLOR.r = reduce_color(raw.r, (dithering_value - 0.5) * dithering_value + 0.5, colors - 1);
		COLOR.g = reduce_color(raw.g, (dithering_value - 0.5) * dithering_value + 0.5, colors - 1);
		COLOR.b = reduce_color(raw.b, (dithering_value - 0.5) * dithering_value + 0.5, colors - 1);

	} else {
		COLOR.rgb = raw.rgb;
	}
}
Tags
godot4, lowpoly, ps1, psx, retro
The shader code and all code snippets in this post are under CC0 license and can be used freely without the author's permission. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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davidrodmad
1 year ago

This rules, thank you!

dancovich
1 year ago

The only dithering shader I ever got to work. Thank you very much for this great work.

Norko
Norko
1 year ago

is there a way to use this in 4;3 aspect ratio?

Chipik
Chipik
1 year ago

How to set spatial?

skyth
skyth
1 year ago
Reply to  Chipik

see usage

skyth
skyth
1 year ago
Reply to  Chipik

if you think most canvas item shaders dont work in 3d.. they do. just add colorrect select anchor preset and check top level in visible
it’ll work
btw feel free to ask me questions if you want
tis my discord username “skyth_.”

Orrte
Orrte
1 year ago
Reply to  Chipik

Hola perdona que lo escriba en español, pero con spatial se refiere a un nodo3D osea el nivel debe estar dentro del subviewport

cortrano
cortrano
1 year ago

Is that possible to use this shader with ColorRect/TextureRect Instead?

ocelotbuck
ocelotbuck
7 days ago
Reply to  cortrano

shader_type canvas_item;

render_mode unshaded;

#define MAXCOLORS 16

uniform bool enabled = true;

// add a line
uniform sampler2D SCREEN_TEXTURE: hint_screen_texture, filter_linear_mipmap, repeat_disable;

void fragment() {
// replace ‘TEXTURE’ with ‘SCREEN_TEXTURE
vec4 raw = texture(SCREEN_TEXTURE, SCREEN_UV);
ivec2 uv = ivec2(FRAGCOORD.xy / float(dither_size));


}

SCRATXH
1 year ago

its just grey

iwin
iwin
1 month ago

How do i make a canvaslayer not to show pixelated, ive got a paper with writing on it that gets pixelated too, but i need it in it’s original form.

Ashhh
1 month ago

You can fix the gray/white issue by:
Adding this line near the top of the file: uniform sampler2D screen_texture: hint_screen_texture;Replacing “TEXTURE” with “screen_texture” in the line vec4 raw = texture(TEXTURE, SCREEN_UV);

Last edited 1 month ago by Ashhh