shader_type spatial;
render_mode unshaded, fog_disabled;

// Noise textures for bubble field and haze effect
group_uniforms noise_textures;
uniform sampler2D displacement_noise_texture: source_color;
uniform sampler2D panning_noise_texture: source_color;
uniform sampler2D haze_noise_texture: source_color;
// For adding a distortion effect of everything inside of the bubble field (screen space)
uniform sampler2D SCREENTEXTURE: hint_screen_texture,repeat_disable,filter_linear_mipmap;

// Colours for the bubble field
group_uniforms colours;
uniform vec4 base_colour: source_color = vec4(0.14, 0.21, 0.57, 1.0);
uniform vec4 secondary_colour: source_color = vec4(0.53, 0.68, 1.0, 1.0);

// Adjustments for the distortion and displacement effects
group_uniforms adjustments;
// For adding wobble to field
uniform float displacement_amount: hint_range(0.0, 1.0, 0.05) = 0.15;
uniform float displacement_speed: hint_range(0.0, 1.0, 0.1) = 0.1;
uniform float distortion_speed: hint_range(0.0, 1.0, 0.1) = 0.1;


// Fresnel function to slightly highlight edges of the field
float fresnel(float amount, vec3 normal, vec3 view)
{
	return pow((1.0 - clamp(dot(normalize(normal), normalize(view)), 0.0, 1.0 )), amount);
}


void vertex() {
	// This adds a wobble to the bubble/forcefield
	float noise_val = texture(displacement_noise_texture, UV +  (TIME * displacement_speed)).r;
	vec3 displacement = NORMAL * noise_val * displacement_amount;
	VERTEX += displacement;
}

void fragment() {
	// Set up force field colour, using noise texture to mix the two
	vec2 noise_panning = vec2(-0.1, 0.0) * TIME + UV;  // Vec2 controls panning direction and speed
	float mix_value = texture(panning_noise_texture, noise_panning).r;  // Mix colours based on noise texture
	vec3 final_colour = mix(base_colour.rgb, secondary_colour.rgb, mix_value);

	// Adding haze
	// Create a distortion offset for the getting screen UV
	float noise = texture(haze_noise_texture, UV + TIME * distortion_speed).r * 2.0;
	vec3 distored_screen = texture(SCREENTEXTURE, SCREEN_UV + noise * 0.01).rgb;

	// Add fresnel
	float fresn = fresnel(5.0, NORMAL, VIEW);

	ALBEDO = final_colour + distored_screen + fresn;
	ALPHA = 0.3;
	EMISSION = final_colour + fresn;
}