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package com.sun.scenario.effect.light;

import com.sun.scenario.effect.Color4f;

Represents a spot light source at a given position in 3D space, with
configurable direction and focus.
/**
 * Represents a spot light source at a given position in 3D space, with
 * configurable direction and focus.
 */
public class SpotLight extends PointLight {

    private float pointsAtX;
    private float pointsAtY;
    private float pointsAtZ;
    private float specularExponent;
    //private float limitingConeAngle;

    
Constructs a new PointLight with default position (0,0,0), direction (pointing at (0,0,0)) and specular exponent (1.0). /**
     * Constructs a new {@code PointLight} with default position (0,0,0),
     * direction (pointing at (0,0,0)) and specular exponent (1.0).
     */
    public SpotLight() {
        this(0f, 0f, 0f, Color4f.WHITE);
    }

    
Constructs a new SpotLight with the given position and color, with the default direction (pointing at (0,0,0)) and specular exponent (1.0). 
Params:
x – the x coordinate of the light position
y – the y coordinate of the light position
z – the z coordinate of the light position
color – the color of the light
Throws:
IllegalArgumentException – if color is null/**
     * Constructs a new {@code SpotLight} with the given position and color,
     * with the default direction (pointing at (0,0,0)) and specular exponent
     * (1.0).
     *
     * @param x the x coordinate of the light position
     * @param y the y coordinate of the light position
     * @param z the z coordinate of the light position
     * @param color the color of the light
     * @throws IllegalArgumentException if {@code color} is null
     */
    public SpotLight(float x, float y, float z, Color4f color) {
        super(Type.SPOT, x, y, z, color);
        this.pointsAtX = 0f;
        this.pointsAtY = 0f;
        this.pointsAtZ = 0f;
        this.specularExponent = 1f;
    }

    
Returns the x coordinate of the direction vector for this light.
Returns:
the x coordinate of the direction vector for this light/**
     * Returns the x coordinate of the direction vector for this light.
     *
     * @return the x coordinate of the direction vector for this light
     */
    public float getPointsAtX() {
        return pointsAtX;
    }

    
Sets the x coordinate of the direction vector for this light.
      Min: n/a
      Max: n/a
  Default: 0.0
 Identity: n/a

Params:
pointsAtX – the x coordinate of the direction vector for this light/**
     * Sets the x coordinate of the direction vector for this light.
     * <pre>
     *       Min: n/a
     *       Max: n/a
     *   Default: 0.0
     *  Identity: n/a
     * </pre>
     *
     * @param pointsAtX the x coordinate of the direction vector for this light
     */
    public void setPointsAtX(float pointsAtX) {
        this.pointsAtX = pointsAtX;
    }

    
Returns the y coordinate of the direction vector for this light.
Returns:
the y coordinate of the direction vector for this light/**
     * Returns the y coordinate of the direction vector for this light.
     *
     * @return the y coordinate of the direction vector for this light
     */
    public float getPointsAtY() {
        return pointsAtY;
    }

    
Sets the y coordinate of the direction vector for this light.
      Min: n/a
      Max: n/a
  Default: 0.0
 Identity: n/a

Params:
pointsAtY – the y coordinate of the direction vector for this light/**
     * Sets the y coordinate of the direction vector for this light.
     * <pre>
     *       Min: n/a
     *       Max: n/a
     *   Default: 0.0
     *  Identity: n/a
     * </pre>
     *
     * @param pointsAtY the y coordinate of the direction vector for this light
     */
    public void setPointsAtY(float pointsAtY) {
        float old = this.pointsAtY;
        this.pointsAtY = pointsAtY;
    }

    
Returns the z coordinate of the direction vector for this light.
Returns:
the z coordinate of the direction vector for this light/**
     * Returns the z coordinate of the direction vector for this light.
     *
     * @return the z coordinate of the direction vector for this light
     */
    public float getPointsAtZ() {
        return pointsAtZ;
    }

    
Sets the z coordinate of the direction vector for this light.
      Min: n/a
      Max: n/a
  Default: 0.0
 Identity: n/a

Params:
pointsAtZ – the z coordinate of the direction vector for this light/**
     * Sets the z coordinate of the direction vector for this light.
     * <pre>
     *       Min: n/a
     *       Max: n/a
     *   Default: 0.0
     *  Identity: n/a
     * </pre>
     *
     * @param pointsAtZ the z coordinate of the direction vector for this light
     */
    public void setPointsAtZ(float pointsAtZ) {
        this.pointsAtZ = pointsAtZ;
    }

    
Returns the specular exponent, which controls the focus of this
light source.
Returns:
the specular exponent of this light/**
     * Returns the specular exponent, which controls the focus of this
     * light source.
     *
     * @return the specular exponent of this light
     */
    public float getSpecularExponent() {
        return specularExponent;
    }

    
Sets the specular exponent, which controls the focus of this
light source.
      Min: 0.0
      Max: 4.0
  Default: 1.0
 Identity: 1.0

Params:
specularExponent – the specular exponent of this light/**
     * Sets the specular exponent, which controls the focus of this
     * light source.
     * <pre>
     *       Min: 0.0
     *       Max: 4.0
     *   Default: 1.0
     *  Identity: 1.0
     * </pre>
     *
     * @param specularExponent the specular exponent of this light
     */
    public void setSpecularExponent(float specularExponent) {
        if (specularExponent < 0f || specularExponent > 4f) {
            throw new IllegalArgumentException("Specular exponent must be in the range [0,4]");
        }
        this.specularExponent = specularExponent;
    }

    @Override
    public float[] getNormalizedLightPosition() {
        // normalize
        float x = getX();
        float y = getY();
        float z = getZ();
        float len = (float)Math.sqrt(x*x + y*y + z*z);
        if (len == 0f) len = 1f;
        float[] pos = new float[] {x/len, y/len, z/len};
        return pos;
    }

    
Returns a float array containing the normalized (x,y,z) direction vector of this light source. 
Returns:
the normalized direction vector of this light source/**
     * Returns a float array containing the normalized {@code (x,y,z)}
     * direction vector of this light source.
     *
     * @return the normalized direction vector of this light source
     */
    public float[] getNormalizedLightDirection() {
        float sx = pointsAtX - getX();
        float sy = pointsAtY - getY();
        float sz = pointsAtZ - getZ();
        // normalize
        float len = (float)Math.sqrt(sx*sx + sy*sy + sz*sz);
        if (len == 0f) len = 1f;
        float[] vec = new float[] {sx/len, sy/len, sz/len};
        return vec;
    }
}