/**
 * Shader specialized in wave like senses (tremorsenses)
 */
class WaveBackgroundVisionShader extends BackgroundVisionShader {

  /** @inheritdoc */
  static fragmentShader = `
  ${this.SHADER_HEADER}
  ${this.WAVE()}
  ${this.PERCEIVED_BRIGHTNESS}
  
  void main() {
    ${this.FRAGMENT_BEGIN}    
    // Normalize vUvs and compute base time
    vec2 uvs = (2.0 * vUvs) - 1.0;
    float t = time * -8.0;
    
    // Rotate uvs
    float sinX = sin(t * 0.02);
    float cosX = cos(t * 0.02);
    mat2 rotationMatrix = mat2( cosX, -sinX, sinX, cosX);
    vec2 ruv = ((vUvs - 0.5) * rotationMatrix) + 0.5;
    
    // Produce 4 arms smoothed to the edges
    float angle = atan(ruv.x * 2.0 - 1.0, ruv.y * 2.0 - 1.0) * INVTWOPI;
    float beam = fract(angle * 4.0);
    beam = smoothstep(0.3, 1.0, max(beam, 1.0 - beam));
    
    // Construct final color
    vec3 grey = vec3(perceivedBrightness(baseColor.rgb));
    finalColor = mix(baseColor.rgb, grey * 0.5, sqrt(beam)) * mix(vec3(1.0), colorTint, 0.3);
    ${this.ADJUSTMENTS}
    ${this.BACKGROUND_TECHNIQUES}
    ${this.FALLOFF}
    ${this.FRAGMENT_END}
  }`;

  /** @inheritdoc */
  static defaultUniforms = ({...super.defaultUniforms, colorTint: [0.8, 0.1, 0.8]});

  /** @inheritdoc */
  get isRequired() {
    return true;
  }
}

/* -------------------------------------------- */

/**
 * The wave vision shader, used to create waves emanations (ex: tremorsense)
 */
class WaveColorationVisionShader extends ColorationVisionShader {

  /** @inheritdoc */
  static fragmentShader = `
  ${this.SHADER_HEADER}
  ${this.WAVE()}
  ${this.PERCEIVED_BRIGHTNESS}
    
  void main() {
    ${this.FRAGMENT_BEGIN}
    // Normalize vUvs and compute base time
    vec2 uvs = (2.0 * vUvs) - 1.0;
    float t = time * -8.0;
    
    // Rotate uvs
    float sinX = sin(t * 0.02);
    float cosX = cos(t * 0.02);
    mat2 rotationMatrix = mat2( cosX, -sinX, sinX, cosX);
    vec2 ruv = ((vUvs - 0.5) * rotationMatrix) + 0.5;
    
    // Prepare distance from 4 corners
    float dst[4];
    dst[0] = distance(vec2(0.0), ruv);
    dst[1] = distance(vec2(1.0), ruv);
    dst[2] = distance(vec2(1.0,0.0), ruv);
    dst[3] = distance(vec2(0.0,1.0), ruv);
    
    // Produce 4 arms smoothed to the edges
    float angle = atan(ruv.x * 2.0 - 1.0, ruv.y * 2.0 - 1.0) * INVTWOPI;
    float beam = fract(angle * 4.0);
    beam = smoothstep(0.3, 1.0, max(beam, 1.0 - beam));
    
    // Computing the 4 corner waves
    float multiWaves = 0.0;
    for ( int i = 0; i <= 3 ; i++) {
      multiWaves += smoothstep(0.6, 1.0, max(multiWaves, wcos(-10.0, 1.30 - dst[i], dst[i] * 120.0, t)));
    }
    // Computing the central wave
    multiWaves += smoothstep(0.6, 1.0, max(multiWaves, wcos(-10.0, 1.35 - dist, dist * 120.0, -t)));
        
    // Construct final color
    finalColor = vec3(mix(multiWaves, 0.0, sqrt(beam))) * colorEffect;
    ${this.COLORATION_TECHNIQUES}
    ${this.ADJUSTMENTS}
    ${this.FALLOFF}
    ${this.FRAGMENT_END}
  }`;

  /** @inheritdoc */
  static defaultUniforms = ({...super.defaultUniforms, colorEffect: [0.8, 0.1, 0.8]});

  /** @inheritdoc */
  get isRequired() {
    return true;
  }
}
