/**
* Example Fragment Shader
* Sets the color and alpha of the pixel by setting gl_FragColor
*/

// Set the precision for data types used in this shader
precision highp float;
precision highp int;

// Default THREE.js uniforms available to both fragment and vertex shader
uniform mat4 modelMatrix;
uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform mat3 normalMatrix;

// Default uniforms provided by ShaderFrog.
uniform vec3 cameraPosition;
uniform float time;
uniform sampler2D noise;

// A uniform unique to this shader. You can modify it to the using the form
// below the shader preview. Any uniform you add is automatically given a form
uniform vec3 color;

// Example varyings passed from the vertex shader
varying vec3 vPosition;
varying vec3 vNormal;
varying vec2 vUv;
varying vec2 vUv2;

void main() {

    // Fragment shaders set the gl_FragColor, which is a vector4 of
    // ( red, green, lue, alpha ).
    float steps = 24.0;
    float step = 1.0 / steps;
    float scale = 0.3;
    float minv = 0.4;
    float maxv = 0.8;
    vec3 top = vec3(1.0, 0.0, 0.0);
    vec3 side = vec3(0.5, 0.5, 0.5);


    float h;
    vec3 col;
    vec2 base = vUv * scale;
    for (int i = -3; i < 3; i++) {
        vec2 ccoord = ((vUv + vec2(0, float(i) * step)) * steps) / steps * scale;
        vec2 coord = floor((vUv + vec2(0, float(i) * step)) * steps) / steps * scale;

        gl_FragColor = vec4(texture2D(noise, coord));
        //return;
        int th = 6 - (i + 3);
        h = texture2D(noise, ccoord).r;
        h = (h - minv) / (maxv - minv);
        int hi = int(floor(h * 6.0));

        gl_FragColor = vec4(vec3(h), 1.0);
        //return;
        float shadow = 1.0 * float(6 - (i + 3)) / 6.0;
        shadow *= (base.y - ccoord.y)*steps*6.0;

        gl_FragColor = vec4(vec3(shadow), 1.0);
        //return;
        if (hi == th) {
            col = top * shadow;
            break;
        } else if (hi > th) {
            //float shadow = (h - th) * (ccoord.y - coord.y) / scale * steps;
            col = side * shadow;
            break;
        }
    }

    gl_FragColor = vec4(col, 1.0);

}