simple fresnel transparency

CountingClowns

A cut-down inverted fresnel function used to provide smoothly disappearing edges, to give a ghostly effect.

It has 2 controls;

edgefade controls the fading of the edges, ranging from 0 (no fading) to 1 (lots of fading)

globalfade is essentially just inverted ALPHA, ranging from 0 (fully visible) to 1 (fully invisible)

Example is unshaded and uses no texture, but you can uncomment the commented lines if your model should have one. ( and comment out / modify the render mode if you want lighting )

Shader code
shader_type spatial;
render_mode unshaded;

uniform lowp float edgefade : hint_range(0, 1) = 0.2;
uniform lowp float globalfade : hint_range(0, 1) = 0.5;
//uniform sampler2D texture: source_color, filter_linear, repeat_disable;

void fragment () {
	float sinvresnel = pow(dot(normalize(NORMAL), normalize(VIEW)), (edgefade*25.0))*(1.0-globalfade);
	ALPHA = sinvresnel;
//	ALBEDO = texture(texture, UV).rgb;
}
Tags
alpha, fade, fresnel, ghost, Transparency, Transparent
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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Kalamster
Kalamster
7 months ago

Good idea, thanks for sharing! I had to clamp the fresnel because of oversampling though.
By adding a noise texture to the alpha and fiddling with UV, this also makes for some nice-looking cheap volumetric fog/clouds:

shader_type spatial;
render_mode blend_mix,depth_draw_opaque,cull_back,diffuse_lambert,specular_schlick_ggx, shadows_disabled;

uniform bool animate_noise = true;
uniform vec2  uv_scroll_speed = vec2(0.01, 0.01);
uniform sampler2D noise;
uniform lowp float edgefade : hint_range(0, 1) = 0.2;
uniform lowp float globalfade : hint_range(0, 1) = 0.5;
varying vec2 uv_scrolled;


void vertex ()
{
uv_scrolled = ( UV + TIME * uv_scroll_speed );
}

void fragment () {
    float sinvresnel = pow(dot(normalize(NORMAL), normalize(VIEW)), (edgefade*25.0))*(1.0-globalfade);
    sinvresnel = clamp(sinvresnel, 0.0, 1.0);
    if(animate_noise){
    vec3 noise_tex = texture(noise, uv_scrolled).rgb;
    ALPHA = sinvresnel * noise_tex.r;
    ALBEDO += noise_tex.rgb;
    }
    else{
    vec3 noise_tex = texture(noise, UV).rgb;
    ALPHA = sinvresnel * noise_tex.r;
    ALBEDO += noise_tex.rgb;
    }
}
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