107 lines
3.4 KiB
Java
107 lines
3.4 KiB
Java
import java.lang.*;
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import java.util.*;
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import algebra.*;
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/* * The Lighting class describes a scene lighting environment
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* @author: gmorin, smondet */
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public class Lighting {
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static final int NONE = 0;
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static final int AMBIENT = 1;
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static final int POINT = 2;
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List<Light> lights;
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/* Internal Class describing a light source */
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private class Light {
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public int type = NONE;
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public double[] params;
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public Light(int type, double[] params) {
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this.type = type;
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this.params = params;
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}
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}
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public Lighting() {
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lights = new LinkedList<Light>();
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}
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/* Adds a new ambient light source of intensity @ia to the environment. */
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public void addAmbientLight(double ia) {
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double[] v = new double[1];
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v[0] = ia;
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lights.add(new Light(AMBIENT, v));
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}
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/** Addsa */
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public void addPointLight(double x, double y, double z, double id) {
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double[] v = new double[5];
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v[0] = x;
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v[1] = y;
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v[2] = z;
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v[3] = id;
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lights.add(new Light(POINT, v));
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}
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/*
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* Computes the illuminated color of a 3D points of given position, normal and
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* color,
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* and given the camera position and material parameters.
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* Returns an array of size 3.
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*/
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public double[] applyLights(Vector3 position, Vector3 normal, double[] color,
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Vector3 cameraPosition,
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double ka, double kd, double ks, double s) {
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double[] litColor = new double[3];
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/* total light intensity */
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double I = 0.0;
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Iterator<Light> it = lights.iterator();
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while (it.hasNext()) {
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Light light = (Light) it.next();
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switch (light.type) {
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case AMBIENT:
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/* Ambient light */
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double Ia = light.params[0];
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I += Ia * ka;
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break;
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case POINT:
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try {
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/* vector from point to camera center */
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Vector3 e = new Vector3(cameraPosition);
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e.subtract(position);
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e.normalize();
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/* vector from point to light */
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Vector3 l = new Vector3(light.params[0], light.params[1], light.params[2]);
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l.subtract(position);
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l.normalize();
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/* half-vector between e and l */
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Vector3 h = new Vector3(e);
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h.add(l);
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h.normalize();
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double Id = light.params[3];
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/* diffuse contribution */
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double I_diff = Id * kd * Math.cos(normal.dot(l));
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/* specular contribution */
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double I_spec = Id * ks * Math.pow(Math.cos(h.dot(normal)), s);
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I += I_diff + I_spec;
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} catch (InstantiationException ex) {
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/* should not reach */ } catch (SizeMismatchException ex) {
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/* should not reach */ }
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break;
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default:
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/* ignore unknow lights */
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break;
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}
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}
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litColor[0] = I * color[0];
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litColor[1] = I * color[1];
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litColor[2] = I * color[2];
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return litColor;
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}
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}
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