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package org.sunflow.core.light;
import org.sunflow.SunflowAPI;
import org.sunflow.core.Instance;
import org.sunflow.core.IntersectionState;
import org.sunflow.core.LightSample;
import org.sunflow.core.LightSource;
import org.sunflow.core.ParameterList;
import org.sunflow.core.PrimitiveList;
import org.sunflow.core.Ray;
import org.sunflow.core.Shader;
import org.sunflow.core.ShadingState;
import org.sunflow.core.Texture;
import org.sunflow.image.Bitmap;
import org.sunflow.image.Color;
import org.sunflow.math.BoundingBox;
import org.sunflow.math.Matrix4;
import org.sunflow.math.OrthoNormalBasis;
import org.sunflow.math.Point3;
import org.sunflow.math.QMC;
import org.sunflow.math.Vector3;
public class ImageBasedLight implements PrimitiveList, LightSource, Shader {
private Texture texture;
private OrthoNormalBasis basis;
private int numSamples;
private int numLowSamples;
private float jacobian;
private float[] colHistogram;
private float[][] imageHistogram;
private Vector3[] samples;
private Vector3[] lowSamples;
private Color[] colors;
private Color[] lowColors;
public ImageBasedLight() {
texture = null;
updateBasis(new Vector3(0, 0, -1), new Vector3(0, 1, 0));
numSamples = 64;
numLowSamples = 8;
}
private void updateBasis(Vector3 center, Vector3 up) {
if (center != null && up != null) {
basis = OrthoNormalBasis.makeFromWV(center, up);
basis.swapWU();
basis.flipV();
}
}
public boolean update(ParameterList pl, SunflowAPI api) {
updateBasis(pl.getVector("center", null), pl.getVector("up", null));
numSamples = pl.getInt("samples", numSamples);
numLowSamples = pl.getInt("lowsamples", numLowSamples);
String filename = pl.getString("texture", null);
if (filename != null)
// EP : Made texture cache local to a SunFlow API instance
texture = api.getTextureCache().getTexture(api.resolveTextureFilename(filename), false);
// no texture provided
if (texture == null)
return false;
Bitmap b = texture.getBitmap();
if (b == null)
return false;
// rebuild histograms if this is a new texture
if (filename != null) {
imageHistogram = new float[b.getWidth()][b.getHeight()];
colHistogram = new float[b.getWidth()];
float du = 1.0f / b.getWidth();
float dv = 1.0f / b.getHeight();
for (int x = 0; x < b.getWidth(); x++) {
for (int y = 0; y < b.getHeight(); y++) {
float u = (x + 0.5f) * du;
float v = (y + 0.5f) * dv;
Color c = texture.getPixel(u, v);
imageHistogram[x][y] = c.getLuminance() * (float) Math.sin(Math.PI * v);
if (y > 0)
imageHistogram[x][y] += imageHistogram[x][y - 1];
}
colHistogram[x] = imageHistogram[x][b.getHeight() - 1];
if (x > 0)
colHistogram[x] += colHistogram[x - 1];
for (int y = 0; y < b.getHeight(); y++)
imageHistogram[x][y] /= imageHistogram[x][b.getHeight() - 1];
}
for (int x = 0; x < b.getWidth(); x++)
colHistogram[x] /= colHistogram[b.getWidth() - 1];
jacobian = (float) (2 * Math.PI * Math.PI) / (b.getWidth() * b.getHeight());
}
// take fixed samples
if (pl.getBoolean("fixed", samples != null)) {
// high density samples
samples = new Vector3[numSamples];
colors = new Color[numSamples];
generateFixedSamples(samples, colors);
// low density samples
lowSamples = new Vector3[numLowSamples];
lowColors = new Color[numLowSamples];
generateFixedSamples(lowSamples, lowColors);
} else {
// turn off
samples = lowSamples = null;
colors = lowColors = null;
}
return true;
}
private void generateFixedSamples(Vector3[] samples, Color[] colors) {
for (int i = 0; i < samples.length; i++) {
double randX = (double) i / (double) samples.length;
double randY = QMC.halton(0, i);
int x = 0;
while (randX >= colHistogram[x] && x < colHistogram.length - 1)
x++;
float[] rowHistogram = imageHistogram[x];
int y = 0;
while (randY >= rowHistogram[y] && y < rowHistogram.length - 1)
y++;
// sample from (x, y)
float u = (float) ((x == 0) ? (randX / colHistogram[0]) : ((randX - colHistogram[x - 1]) / (colHistogram[x] - colHistogram[x - 1])));
float v = (float) ((y == 0) ? (randY / rowHistogram[0]) : ((randY - rowHistogram[y - 1]) / (rowHistogram[y] - rowHistogram[y - 1])));
float px = ((x == 0) ? colHistogram[0] : (colHistogram[x] - colHistogram[x - 1]));
float py = ((y == 0) ? rowHistogram[0] : (rowHistogram[y] - rowHistogram[y - 1]));
float su = (x + u) / colHistogram.length;
float sv = (y + v) / rowHistogram.length;
float invP = (float) Math.sin(sv * Math.PI) * jacobian / (numSamples * px * py);
samples[i] = getDirection(su, sv);
basis.transform(samples[i]);
colors[i] = texture.getPixel(su, sv).mul(invP);
}
}
public void prepareShadingState(ShadingState state) {
if (state.includeLights())
state.setShader(this);
}
public void intersectPrimitive(Ray r, int primID, IntersectionState state) {
if (r.getMax() == Float.POSITIVE_INFINITY)
state.setIntersection(0);
}
public int getNumPrimitives() {
return 1;
}
public float getPrimitiveBound(int primID, int i) {
return 0;
}
public BoundingBox getWorldBounds(Matrix4 o2w) {
return null;
}
public PrimitiveList getBakingPrimitives() {
return null;
}
public int getNumSamples() {
return numSamples;
}
public void getSamples(ShadingState state) {
if (samples == null) {
int n = state.getDiffuseDepth() > 0 ? 1 : numSamples;
for (int i = 0; i < n; i++) {
// random offset on unit square, we use the infinite version of
// getRandom because the light sampling is adaptive
double randX = state.getRandom(i, 0, n);
double randY = state.getRandom(i, 1, n);
int x = 0;
while (randX >= colHistogram[x] && x < colHistogram.length - 1)
x++;
float[] rowHistogram = imageHistogram[x];
int y = 0;
while (randY >= rowHistogram[y] && y < rowHistogram.length - 1)
y++;
// sample from (x, y)
float u = (float) ((x == 0) ? (randX / colHistogram[0]) : ((randX - colHistogram[x - 1]) / (colHistogram[x] - colHistogram[x - 1])));
float v = (float) ((y == 0) ? (randY / rowHistogram[0]) : ((randY - rowHistogram[y - 1]) / (rowHistogram[y] - rowHistogram[y - 1])));
float px = ((x == 0) ? colHistogram[0] : (colHistogram[x] - colHistogram[x - 1]));
float py = ((y == 0) ? rowHistogram[0] : (rowHistogram[y] - rowHistogram[y - 1]));
float su = (x + u) / colHistogram.length;
float sv = (y + v) / rowHistogram.length;
float invP = (float) Math.sin(sv * Math.PI) * jacobian / (n * px * py);
Vector3 dir = getDirection(su, sv);
basis.transform(dir);
if (Vector3.dot(dir, state.getGeoNormal()) > 0) {
LightSample dest = new LightSample();
dest.setShadowRay(new Ray(state.getPoint(), dir));
dest.getShadowRay().setMax(Float.MAX_VALUE);
Color radiance = texture.getPixel(su, sv);
dest.setRadiance(radiance, radiance);
dest.getDiffuseRadiance().mul(invP);
dest.getSpecularRadiance().mul(invP);
dest.traceShadow(state);
state.addSample(dest);
}
}
} else {
if (state.getDiffuseDepth() > 0) {
for (int i = 0; i < numLowSamples; i++) {
if (Vector3.dot(lowSamples[i], state.getGeoNormal()) > 0 && Vector3.dot(lowSamples[i], state.getNormal()) > 0) {
LightSample dest = new LightSample();
dest.setShadowRay(new Ray(state.getPoint(), lowSamples[i]));
dest.getShadowRay().setMax(Float.MAX_VALUE);
dest.setRadiance(lowColors[i], lowColors[i]);
dest.traceShadow(state);
state.addSample(dest);
}
}
} else {
for (int i = 0; i < numSamples; i++) {
if (Vector3.dot(samples[i], state.getGeoNormal()) > 0 && Vector3.dot(samples[i], state.getNormal()) > 0) {
LightSample dest = new LightSample();
dest.setShadowRay(new Ray(state.getPoint(), samples[i]));
dest.getShadowRay().setMax(Float.MAX_VALUE);
dest.setRadiance(colors[i], colors[i]);
dest.traceShadow(state);
state.addSample(dest);
}
}
}
}
}
public void getPhoton(double randX1, double randY1, double randX2, double randY2, Point3 p, Vector3 dir, Color power) {
}
public Color getRadiance(ShadingState state) {
// lookup texture based on ray direction
return state.includeLights() ? getColor(basis.untransform(state.getRay().getDirection(), new Vector3())) : Color.BLACK;
}
private Color getColor(Vector3 dir) {
float u, v;
// assume lon/lat format
double phi = 0, theta = 0;
phi = Math.acos(dir.y);
theta = Math.atan2(dir.z, dir.x);
u = (float) (0.5 - 0.5 * theta / Math.PI);
v = (float) (phi / Math.PI);
return texture.getPixel(u, v);
}
private Vector3 getDirection(float u, float v) {
Vector3 dest = new Vector3();
double phi = 0, theta = 0;
theta = u * 2 * Math.PI;
phi = v * Math.PI;
double sin_phi = Math.sin(phi);
dest.x = (float) (-sin_phi * Math.cos(theta));
dest.y = (float) Math.cos(phi);
dest.z = (float) (sin_phi * Math.sin(theta));
return dest;
}
public void scatterPhoton(ShadingState state, Color power) {
}
public float getPower() {
return 0;
}
public Instance createInstance() {
return Instance.createTemporary(this, null, this);
}
// EP : Added transparency management
public boolean isOpaque() {
return true;
}
public Color getOpacity(ShadingState state) {
return null;
}
// EP : End of modification
}
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