Translucent terminals. Works with any terminal emulator, as long as the background is black.

compositor.sh

#!/bin/sh

# Runs compton with a shader that only applies the opacity property to black
# backgrounds, with small soft shadows around non-black parts to inprove
# readability.

exec compton --backend glx --vsync --glx-fshader-win '
uniform float opacity;
uniform sampler2D tex;
void main() {
	float max_a = 0;
	vec4 pixel = texture2D(tex, gl_TexCoord[0]);
	if (opacity < 1) {
		vec2 ss = textureSize(tex, 0);
		for (float x = -3; x <= 3; x += 1)
		for (float y = -3; y <= 3; y += 1) {
			vec2 offset = vec2(x, y);
			vec4 c = texture2D(tex, gl_TexCoord[0] + offset / ss);
			float b = dot(vec3(0.299, 0.587, 0.114), c.rgb);
			float a = pow(b, 0.4);
			if (offset != vec2(0, 0)) a /= pow(length(offset) / 4, 3) * 10 + 1;
			max_a = max(max_a, a);
		}
		pixel.a *= mix(opacity, 1, max_a);
	}
	gl_FragColor = pixel;
}' \
	--opacity-rule="85:class_g='XTerm'" \
	--opacity-rule="85:class_g='URxvt'" \
	--opacity-rule="85:class_g='Gnome-terminal'"
# Add your own terminal emulators above. (You can use xprop to find the class.)
# Change the '85' for more/less background opacity. And/or configure your
# window manager with hotkeys to increase/decrease the opacity of windows.

thank you. now to get animated shaders!