Dynamic Glow

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Here’s how you can set up the shader:

  1. Create Sprite:

    • Add a Sprite2D node and assign a texture to it.
  2. Create Inverted Sprite:

    • Add another Sprite2D node.
    • Assign the inverted texture to this sprite.
    • Apply the shader material to this inverted sprite.
  3. Ensure Both Sprites are Aligned:

    • Position the inverted sprite exactly on top of the original sprite.
  4. Configure the Shader Parameters:

    • Adjust the glow_position, glow_size, glow_strength, glow_intensity, and other parameters to fit your new sprite.
    • If you want the glow to pulsate, set the pulsate parameter to true and configure the pulsation_speed, glow_intensity_start, and glow_intensity_stop parameters
Shader code
shader_type canvas_item; 
render_mode blend_add;

uniform float fireball_scale_y = 1.0;
uniform float glow_scale_y = 1.0;
uniform float glow_strength = 1.0;
uniform float glow_intensity = 0.0; // Default value for glow_intensity
uniform sampler2D noise : repeat_enable, filter_nearest_mipmap_anisotropic;
uniform sampler2D noise2 : repeat_enable, filter_nearest_mipmap_anisotropic;
uniform sampler2D colo_curve; 
uniform int pixel_size : hint_range(1, 100) = 1;

// Parameters for position and size
uniform vec2 glow_position = vec2(0.5, 0.5);
uniform vec2 glow_size = vec2(0.2, 0.2);

// Parameters for pulsating effect
uniform bool pulsate = false;
uniform float pulsation_speed = 1.0;
uniform float glow_intensity_start = 0.75;
uniform float glow_intensity_stop = 1.0;

vec4 f1(vec2 uv, float time){
	vec4 nv2 = texture(noise, uv + vec2(time, 0.0));
	vec4 n2v2 = texture(noise2, uv + vec2(time*.8, 0.0));
	nv2.r = max(0., nv2.r + uv.x - 1.0);
	n2v2.r = max(0., n2v2.r + uv.x - 1.0); 
	return nv2 * n2v2;
}
	
void fragment()
{ 	
	vec2 mUV = (UV - glow_position) / glow_size;
	vec2 uv = (mUV - 0.5) * 2.0 * vec2(1.0, fireball_scale_y); 
	float time = TIME;
    vec2 cuv = mUV - vec2(0.5); 
	float d2c = length(cuv);
	vec4 color = COLOR;
	// 
	color *= (f1(uv, time) + f1(uv + vec2(0.1, 0.0), time + 11.514) + f1(uv + vec2(0.05, 0.0), time + 14.14));
	
	color.r -= 1.0;
	color.r = -pow(color.r, 2.0) + 1.0;
	//
	color.rgb = texture(colo_curve, vec2(color.r, 0.0)).rgb;
	float randmoo = texture(noise2, mUV + vec2(time, -time)).r;
	randmoo = mix(randmoo, 0.0, mUV.x);
    color.r *= smoothstep(0.5, 0.48 - (0.2 - min(mUV.x, 1.0) * 0.2), d2c + randmoo * 0.4);
    COLOR = color;
	COLOR.rgb = mix(COLOR.rgb, vec3(0.0), smoothstep(0.00001, 0.0, color.r));
	// light
	vec2 glowUV = (UV - glow_position) / glow_size;
	float d2c_l = length(glowUV * vec2(1.0, glow_scale_y) - vec2(0.58, 0.5 * glow_scale_y));
	
	// Oscillating glow_intensity if pulsate is true, otherwise use the default glow_intensity
	float glow_intensity_value = pulsate ? mix(glow_intensity_start, glow_intensity_stop, 0.5 + 0.5 * sin(time * pulsation_speed * 3.14159 * 2.0)) : glow_intensity;
	
	float l = -log(d2c_l + glow_intensity_value) * glow_strength;
	float randmoo2 = texture(noise2, vec2(time, -time)).r;
	
	COLOR += texture(colo_curve, vec2(1.0 - d2c_l - 0.1 * randmoo2, 0.0)) * l;
	//COLOR += vec4(0.8, 0.8, 0.6, 1.0) * l;
	//
	color.r *= smoothstep(0.5, 0.1, length(UV - vec2(0.5)));
	
	vec2 pos = UV / TEXTURE_PIXEL_SIZE;
	vec2 square = vec2(float(pixel_size), float(pixel_size));
	vec2 top_left = floor(pos / square) * square;
	vec4 total = vec4(0.0, 0.0, 0.0, 0.0);
	for (int x = int(top_left.x); x < int(top_left.x) + pixel_size; x++){
		for (int y = int(top_left.y); y < int(top_left.y) + pixel_size; y++){
			total += texture(TEXTURE, vec2(float(x), float(y)) * TEXTURE_PIXEL_SIZE);
		}
	}
	COLOR -= total / float(pixel_size * pixel_size);
}
Tags
glow, lighting, pulsate
The shader code and all code snippets in this post are under CC0 license and can be used freely without the author's permission. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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