#version 300 es
precision highp float;

uniform sampler2D u_texture;
uniform vec2 u_resolution;
uniform float u_time;
in vec2 v_texCoord;
out vec4 fragColor;

const float LEVELS = 15.0; // Number of color levels

void main() {
    vec2 uv = gl_FragCoord.xy/u_resolution.xy;

    // Sample the input texture
    vec4 color = texture(u_texture, uv);

    // Quantize colors to specified number of levels
    vec3 quantized = floor(color.rgb * LEVELS) / (LEVELS - 1.0);

    fragColor = vec4(quantized, color.a);
}