copy from thegates-jam repo

player/model/materials/face_mat.gdshader

@@ -0,0 +1,40 @@
+shader_type spatial;
+
+uniform sampler2D face_texture : filter_nearest, repeat_disable;
+uniform float intensity = 1.5;
+uniform vec4 screen_color : source_color = vec4(1.0);
+
+uniform vec2 screen_red_offset = vec2(0.0);
+uniform vec2 screen_green_offset = vec2(0.0);
+uniform vec2 screen_blue_offset = vec2(0.0);
+
+uniform float pixel_size = 20.0;
+
+void fragment() {
+	
+	vec2 scaled_uv = round(UV * pixel_size) / pixel_size;
+	
+	float face_red = 1.0 - texture(face_texture, screen_red_offset + scaled_uv).x;
+	float face_green = 1.0 - texture(face_texture, screen_green_offset +  scaled_uv).x;
+	float face_blue = 1.0 - texture(face_texture, screen_blue_offset + scaled_uv).x;
+	
+	vec2 grid_2d = sin(fract(UV * pixel_size + 0.5) * 3.14);
+	float grid = grid_2d.x * grid_2d.y;
+	grid = grid * 0.6 + 0.4;
+	
+	ALBEDO = vec3(0.0);
+	SPECULAR = 0.25;
+	ROUGHNESS = 0.45;
+	
+	vec3 iris = vec3(0.0);
+	
+	iris.r = ((screen_color.r * face_red) / 3.0);
+	iris.g = ((screen_color.g * face_green)  / 3.0);
+	iris.b = ((screen_color.b * face_blue)  / 3.0);
+	iris.rgb *= 1.0 - screen_color.a;
+	
+	vec3 fill = screen_color.rgb * screen_color.a;
+	
+	EMISSION = (iris + fill) * grid * intensity;
+	
+}