lava.gdshader

shader_type canvas_item;
uniform sampler2D noise_texture: repeat_enable, filter_nearest;
uniform sampler2D screen_texture: hint_screen_texture, repeat_disable, filter_nearest;
uniform vec2 position = vec2(0,0);
uniform float move_x = 1.0;
uniform float move_y = 1.0;

void vertex() {
    // Called for every vertex the material is visible on.
}

void fragment() {
    // Called for every pixel the material is visible on.
    vec4 red_color = vec4(1.,0.2,0.,1.);
    vec4 yellow_color = vec4(1.,0.4,0.,1.);
    float effect_strength = 1.;
	vec2 offset = position;
	offset.x *= move_x;
	offset.y *= move_y;
    vec2 uv = UV + (offset * 0.0025) * 0.5;
    float noise_texture_val = texture(noise_texture,uv + vec2(0.,1.)*TIME/20.).r;
    float sample_distance = 8.;

    bool foundSample = false;
    float sampleNum = 0.0;
    while(sampleNum < sample_distance && !foundSample){
        if(texture(screen_texture,SCREEN_UV + vec2(0.,0.007)*sampleNum).r > 0.55){
            foundSample = true;
        }
        sampleNum = sampleNum + sample_distance/10.;
    }

    vec4 color = texture(screen_texture,SCREEN_UV);
    if(foundSample){
		effect_strength -= smoothstep(0.9,1.,SCREEN_UV.y);
		effect_strength = clamp(effect_strength,0.,10);
        color += noise_texture_val*red_color*((sample_distance-sampleNum)/sample_distance)*effect_strength;
        color += noise_texture_val*yellow_color*((sample_distance/2.-clamp(sampleNum,0.,5.))/sample_distance/2.)*effect_strength;
    }
    if(texture(screen_texture,vec2(SCREEN_UV)).r > 0.55){
        float noise_texture_val_2 = texture(noise_texture,uv + vec2(0.5,0.5)*TIME/20.).r;
        color += smoothstep(0.6,1.,noise_texture_val_2/2. + noise_texture_val/2.)*1.2;
    }
	color.a = 0.45;
    COLOR = color;
}

//void light() {
    // Called for every pixel for every light affecting the CanvasItem.
    // Uncomment to replace the default light processing function with this one.
//}