Texture based alpha hash

Tired of messy, noisy alpha hash? Try using this ordered alternative!

how to use:

– Create any shader that uses transparency (ALPHA)

– Add the part below the comments to the bottom of your shader.

– Make sure you have a scale and img parameter. Import an appropriate png for the img parameter. You may use one of the ones I put here but do not they are a bit rushed, and a better alternative is possible.

– Adjust the scale to your wishes. 

– For a spatial shader, instead use this to calculate screenpos

vec2 screenpos = SCREEN_UV/SCREEN_PIXEL_SIZE * SCREEN_PIXEL_SIZE.y /(scale);

Shader code

shader_type spatial;

uniform float scale = .01;
uniform sampler2D img; //import a pattern png. You can actually replace this with a white noise texture for the usual alpha hash

void fragment() {
    ALPHA = UV.g*2.-0.3; // sample UV code

// The part below this is the part that actually matters. Make sure you have the scale and img parameters (or replace the scale parameter with a number) then add the script below.

// You can also remove the ALPHA=1. part and replace ALPHA with a variable for honestly slightly cleaner code.

    vec2 screenpos = SCREEN_UV*VIEWPORT_SIZE / VIEWPORT_SIZE.y /(scale);
    float alphatexture = texture(img, (screenpos)).r;
    if (ALPHA < alphatexture) {
         discard;
    }
    ALPHA = 1.;
}

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