uniform mat4 u_Color;
varying vec2 v_TexCoord;
varying vec2 v_TexCoord2;
varying vec2 v_TexCoord3;
varying vec2 v_Position;
uniform sampler2D u_Tex0;
uniform float u_Time;
uniform vec2 u_Resolution;

vec3 outline_color = vec3(0.0, 1.0, 1.5);
float outline_alpha = 0.75;
float outline_color_threshold = 2.5;
float outline_thickness = 0.02;

void main()
{
    gl_FragColor = texture2D(u_Tex0, v_TexCoord);
    vec4 texcolor = texture2D(u_Tex0, v_TexCoord2);
    vec4 texcolor2 = texture2D(u_Tex0, v_TexCoord3);

    if (texcolor.r > outline_color_threshold) {
        if (texcolor.g > outline_color_threshold) {
            gl_FragColor *= u_Color[0];  // Apply outline_color if both R and G channels exceed the threshold
        } else {
            gl_FragColor *= u_Color[1];  // Apply outline_color if only R channel exceeds the threshold
        }
    } else if (texcolor.g > outline_color_threshold) {
        gl_FragColor *= u_Color[2];  // Apply outline_color if only G channel exceeds the threshold
    } else if (texcolor.b > outline_color_threshold) {
        gl_FragColor *= u_Color[3];  // Apply outline_color if only B channel exceeds the threshold
    }
    // Check alpha threshold and apply outline effect
    if (gl_FragColor.a < 0.01) {
        if (texcolor2.a > 0.01) {
            // Apply outline effect with specified parameters
            float outlineAnimation = abs(0.5 - mod(u_Time, 1.0));
            float outlineWidth = smoothstep(outline_thickness, outline_thickness + 0.01, length(v_Position));
            vec3 outlineColor = mix(gl_FragColor.rgb, outline_color, outlineWidth * outlineAnimation);
            gl_FragColor = vec4(outlineColor, 1.0);
            gl_FragColor.a *= outline_alpha;
        } else {
            discard;  // Discard fragments below the alpha threshold
        }
    }
}