Add buff/debuff/heal/rust shaders for enemies and throwing glue jar immobilization

Zennysoft.Game.Ma/src/vfx/shaders/EnemyRust.gdshader

@@ -0,0 +1,29 @@
+shader_type canvas_item;
+
+/**
+Color to use for the shock.
+*/
+uniform vec3 shock_color : source_color = vec3(0.6, 0.3, 0.0);
+/**
+Initial amplitude of the shock. This will start at this amplitude and
+gradually attenuate.
+*/
+uniform float amplitude = 30.0;
+
+uniform float progress: hint_range(0.0, 1.0) = -1.0;
+/**
+How fast shold it move side to side, more frequency means it'll move more quickly
+side to side.
+*/
+uniform float frequecy = 10.0;
+
+void vertex() {
+	float exponent = mod(progress, 3.0);
+	VERTEX.x += amplitude * exp(-3.0*exponent) * sin(frequecy*exponent);
+}
+
+void fragment() {
+	float exponent = mod(progress, 3.0);
+	vec3 normal_color = texture(TEXTURE, UV).rgb;
+	COLOR.rgb = normal_color + shock_color * exp(-3.0*exponent);
+}