some diffuse added for funzies

shaders/dissolve.gdshader

@@ -5,7 +5,16 @@ uniform sampler2D sim_texture;
 uniform float decay_factor;
 
 void fragment() {
-	float c = texture(sim_texture, UV).r;
-	c = c * decay_factor;
-	COLOR = vec4(c, c, c, 1.0);
+	vec3 orig = texture(sim_texture, UV).rgb;
+	float trail = texture(sim_texture, UV).g;
+
+	float sum = 0.0;
+	for(int i=-1;i<=1;i++) {
+		for(int j=-1;j<=1;j++) {
+			sum += texture(sim_texture, UV).g;
+		}
+	}
+	trail = sum / 9.0;
+	trail = trail * decay_factor;
+	COLOR = vec4(orig.r, trail, orig.b, 1.0);
 }