/**
* Prepare the light for rendering.
*
* @param width the output image width
* @param height the output image height
*/
public void prepare(int width, int height) {
float lx = (float) (Math.cos(azimuth) * Math.cos(elevation));
float ly = (float) (Math.sin(azimuth) * Math.cos(elevation));
float lz = (float) Math.sin(elevation);
direction = new Vector3f(lx, ly, lz);
direction.normalize();
if (type != DISTANT) {
lx *= distance;
ly *= distance;
lz *= distance;
lx += width * centreX;
ly += height * centreY;
}
position = new Vector3f(lx, ly, lz);
realColor.set(new Color(color));
realColor.scale(intensity);
cosConeAngle = (float) Math.cos(coneAngle);
}
protected Color4f phongShade(
Vector3f position,
Vector3f viewpoint,
Vector3f normal,
Color4f diffuseColor,
Color4f specularColor,
Material material,
Light[] lightsArray) {
shadedColor.set(diffuseColor);
shadedColor.scale(material.ambientIntensity);
for (int i = 0; i < lightsArray.length; i++) {
Light light = lightsArray[i];
n.set(normal);
l.set(light.position);
if (light.type != DISTANT) l.sub(position);
l.normalize();
float nDotL = n.dot(l);
if (nDotL >= 0.0) {
float dDotL = 0;
v.set(viewpoint);
v.sub(position);
v.normalize();
// Spotlight
if (light.type == SPOT) {
dDotL = light.direction.dot(l);
if (dDotL < light.cosConeAngle) continue;
}
n.scale(2.0f * nDotL);
n.sub(l);
float rDotV = n.dot(v);
float rv;
if (rDotV < 0.0) rv = 0.0f;
else
// rv = (float)Math.pow(rDotV, material.highlight);
rv =
rDotV
/ (material.highlight
- material.highlight * rDotV
+ rDotV); // Fast approximation to pow
// Spotlight
if (light.type == SPOT) {
dDotL = light.cosConeAngle / dDotL;
float e = dDotL;
e *= e;
e *= e;
e *= e;
e = (float) Math.pow(dDotL, light.focus * 10) * (1 - e);
rv *= e;
nDotL *= e;
}
diffuse_color.set(diffuseColor);
diffuse_color.scale(material.diffuseReflectivity);
diffuse_color.x *= light.realColor.x * nDotL;
diffuse_color.y *= light.realColor.y * nDotL;
diffuse_color.z *= light.realColor.z * nDotL;
specular_color.set(specularColor);
specular_color.scale(material.specularReflectivity);
specular_color.x *= light.realColor.x * rv;
specular_color.y *= light.realColor.y * rv;
specular_color.z *= light.realColor.z * rv;
diffuse_color.add(specular_color);
diffuse_color.clamp(0, 1);
shadedColor.add(diffuse_color);
}
}
shadedColor.clamp(0, 1);
return shadedColor;
}
