Colored Tunnel Shader
A shader to produce the effect of objects disapearing into a solid color/ portal.
Shader code
shader_type spatial;
render_mode unshaded;
uniform sampler2D depth_texture : hint_depth_texture;
uniform vec3 color : source_color;
uniform float hole_depth : hint_range(0.1, 10.0, 0.1) = 1.0;
void fragment() {
// sample our depth buffer
float depth = texture(depth_texture, SCREEN_UV).r;
float linear_depth = 1.0 / (depth * INV_PROJECTION_MATRIX[2].w + INV_PROJECTION_MATRIX[3].w);
linear_depth = linear_depth + VERTEX.z;
ALBEDO = color;
ALPHA = 1.-clamp(1.-(linear_depth / hole_depth), 0., 1.);
}