From aede861fb31bf60ceebd50d830b531672c180636 Mon Sep 17 00:00:00 2001
From: Wenzel Jakob <wenzel@cs.cornell.edu>
Date: Fri, 22 Oct 2010 21:42:16 +0200
Subject: [PATCH] work on hair primitive

---
 SConstruct              |   3 +-
 src/shapes/cylinder.cpp |   1 -
 src/shapes/hair.cpp     | 207 +++++++++++++++++++++++++---------------
 src/shapes/hair_old.cpp | 103 ++++++++++++++++++++
 4 files changed, 232 insertions(+), 82 deletions(-)
 create mode 100644 src/shapes/hair_old.cpp

diff --git a/SConstruct b/SConstruct
index 6211c66b..62d3c92c 100644
--- a/SConstruct
+++ b/SConstruct
@@ -511,7 +511,6 @@ plugins += env.SharedLibrary('plugins/roughglass', ['src/bsdfs/roughglass.cpp'])
 plugins += env.SharedLibrary('plugins/roughmetal', ['src/bsdfs/roughmetal.cpp'])
 plugins += env.SharedLibrary('plugins/composite', ['src/bsdfs/composite.cpp'])
 
-
 # Phase functions
 plugins += env.SharedLibrary('plugins/isotropic', ['src/phase/isotropic.cpp'])
 plugins += env.SharedLibrary('plugins/hg', ['src/phase/hg.cpp'])
@@ -524,7 +523,7 @@ plugins += env.SharedLibrary('plugins/ply', ['src/shapes/ply/ply.cpp', 'src/shap
 plugins += env.SharedLibrary('plugins/serialized', ['src/shapes/serialized.cpp'])
 plugins += env.SharedLibrary('plugins/sphere', ['src/shapes/sphere.cpp'])
 plugins += env.SharedLibrary('plugins/cylinder', ['src/shapes/cylinder.cpp'])
-#plugins += env.SharedLibrary('plugins/hair', ['src/shapes/hair.cpp', 'src/shapes/miterseg.cpp'])
+#plugins += env.SharedLibrary('plugins/hair', ['src/shapes/hair.cpp'])
 #plugins += env.SharedLibrary('plugins/group', ['src/shapes/group.cpp'])
 
 # Samplers
diff --git a/src/shapes/cylinder.cpp b/src/shapes/cylinder.cpp
index 07a1aa8a..b93ebc71 100644
--- a/src/shapes/cylinder.cpp
+++ b/src/shapes/cylinder.cpp
@@ -21,7 +21,6 @@
 #include <mitsuba/render/subsurface.h>
 #include <mitsuba/render/luminaire.h>
 #include <mitsuba/core/properties.h>
-#include <mitsuba/core/random.h>
 
 MTS_NAMESPACE_BEGIN
 
diff --git a/src/shapes/hair.cpp b/src/shapes/hair.cpp
index b75137e7..426b6bcf 100644
--- a/src/shapes/hair.cpp
+++ b/src/shapes/hair.cpp
@@ -1,103 +1,152 @@
-#include <fstream>
+/*
+    This file is part of Mitsuba, a physically based rendering system.
+
+    Copyright (c) 2007-2010 by Wenzel Jakob and others.
+
+    Mitsuba is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License Version 3
+    as published by the Free Software Foundation.
+
+    Mitsuba is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
 
 #include <mitsuba/render/shape.h>
 #include <mitsuba/render/bsdf.h>
-#include <mitsuba/core/plugin.h>
+#include <mitsuba/render/subsurface.h>
+#include <mitsuba/render/luminaire.h>
+#include <mitsuba/core/properties.h>
+#include <mitsuba/core/fstream.h>
 #include <mitsuba/core/fresolver.h>
 
-#include "hair.h"
-#include "miterseg.h"
-
 MTS_NAMESPACE_BEGIN
 
-Hair::Hair(const Properties &props) : Shape(props) {
-	std::string filename = props.getString("filename");
+class Hair : public Shape {
+public:
+	Hair(const Properties &props) : Shape(props) {
+		fs::path path = Thread::getThread()->getFileResolver()->resolve(
 			props.getString("filename"));
-	m_radius = (Float) props.getFloat("radius", 0.05f);
-	m_name = FileResolver::getInstance()->resolve(filename);
+		m_radius = (Float) props.getFloat("radius", 0.05f);
 
-	Log(EInfo, "Loading hair geometry from \"%s\" ..", m_name.c_str());
+		Log(EInfo, "Loading hair geometry from \"%s\" ..", path.leaf().c_str());
 
-	std::ifstream is(m_name.c_str());
-	if (is.fail())
-		Log(EError, "Could not open \"%s\"!", m_name.c_str());
+		fs::ifstream is(path);
+		if (is.fail())
+			Log(EError, "Could not open \"%s\"!", path.file_string().c_str());
 
-	std::string line;
-	bool newFiber = true;
-	Point p;
-	while (is.good()) {
-		std::getline(is, line);
-		if (line.length() > 0 && line[0] == '#')
-			continue;
-		if (line.length() == 0) {
-			newFiber = true;
-		} else {
-			std::istringstream iss(line);
-			iss >> p.x >> p.y >> p.z;
-			if (!iss.fail()) {
-				m_vertices.push_back(p);
-				m_startFiber.push_back(newFiber);
-				newFiber = false;
+		std::string line;
+		bool newFiber = true;
+		Point p;
+		size_t segmentCount = 0;
+
+		while (is.good()) {
+			std::getline(is, line);
+			if (line.length() > 0 && line[0] == '#')
+				continue;
+			if (line.length() == 0) {
+				newFiber = true;
+			} else {
+				std::istringstream iss(line);
+				iss >> p.x >> p.y >> p.z;
+				if (!iss.fail()) {
+					if (newFiber)
+						segmentCount++;
+					m_vertices.push_back(p);
+					m_startFiber.push_back(newFiber);
+					newFiber = false;
+				}
 			}
 		}
+		m_startFiber.push_back(true);
+
+		for (size_t i=0; i<m_vertices.size()-1; ++i) {
+			const Point a = firstVertex();
+			const Point b = secondVertex();
+
+			// cosine of steepest miter angle
+			const Float cos0 = dot(firstMiterNormal(), tangent());
+			const Float cos1 = dot(secondMiterNormal(), tangent());
+			const Float maxInvCos = 1.0 / std::min(cos0, cos1);
+			const Vector expandVec(m_radius * maxIvCos);
+
+			result.expandBy(a - expandVec);
+			result.expandBy(a + expandVec);
+			result.expandBy(b - expandVec);
+			result.expandBy(b + expandVec);
+
+		}
+
+		Log(EDebug, "Read " SIZE_T_FMT " hair vertices, " SIZE_T_FMT " segments,", 
+			m_vertices.size(), segmentCount);
 	}
-	m_startFiber.push_back(true);
 
-	buildSegIndex();
+	Hair(Stream *stream, InstanceManager *manager) 
+		: Shape(stream, manager) {
+	}
+	
+	inline Vector tangent(int iv) const {
+		return normalize(m_vertices[iv+1] - m_vertices[iv]);
+	}
 
-	Log(EDebug, "Read %i hair vertices, %i segments,", m_vertices.size(), m_segIndex.size());
-}
+	inline Vector firstMiterNormal(int iv) const {
+		if (!m_startFiber[iv])
+			return normalize(tangent(iv - 1) + tangent(iv));
+		else
+			return tangent(iv);
+	}
 
-Hair::Hair(Stream *stream, InstanceManager *manager) : Shape(stream, manager) {
-	m_radius = stream->readFloat();
-	size_t segmentCount = stream->readUInt();
-
-	m_vertices.reserve(segmentCount);
-	for (size_t i=0; i<segmentCount; ++i)
-		m_vertices.push_back(Point(stream));
-
-	m_startFiber.reserve(segmentCount+1);
-	for (size_t i=0; i<segmentCount+1; ++i)
-		m_startFiber.push_back(stream->readBool());
-
-	buildSegIndex();
-}
-
-void Hair::serialize(Stream *stream, InstanceManager *manager) const {
-	Shape::serialize(stream, manager);
-
-	stream->writeFloat(m_radius);
-	size_t segmentCount = m_vertices.size();
-	stream->writeUInt(segmentCount);
-
-	for (size_t i=0; i<segmentCount; ++i)
-		m_vertices[i].serialize(stream);
-
-	for (size_t i=0; i<segmentCount; ++i)
-		stream->writeBool(m_startFiber[i]);
-}
-
-Shape *Hair::getElement(int index) {
-	if ((size_t) index >= m_segIndex.size())
-		return NULL;
-
-	MiterHairSegment *segment = new MiterHairSegment(this, m_segIndex[index]);
-	segment->addChild("bsdf", m_bsdf);
-	segment->configure();
-	return segment;
-}
+	inline Vector secondMiterNormal(int iv) const {
+		if (!m_startFiber[iv+2])
+			return normalize(tangent(iv) + tangent(iv+1));
+		else
+			return tangent();
+	}
 
 
-void Hair::buildSegIndex() {
-	// Compute the index of the first vertex in each segment.
-	m_segIndex.clear();
-	for (size_t i=0; i<m_vertices.size(); i++)
-		if (!m_startFiber[i+1])
-			m_segIndex.push_back(i);
-}
+	void serialize(Stream *stream, InstanceManager *manager) const {
+		Shape::serialize(stream, manager);
+	}
+
+	bool rayIntersect(const Ray &_ray, Float mint, Float maxt, Float &t, void *temp) const {
+		return false;
+	}
 
 
+	void fillIntersectionRecord(const Ray &ray, Float t, 
+			const void *temp, Intersection &its) const {
+	}
+
+	inline AABB getAABB() const {
+		return m_aabb;
+	}
+
+	Float getSurfaceArea() const {
+		Log(EError, "Hair::getSurfaceArea(): Not implemented.");
+		return -1;
+	}
+
+	std::string toString() const {
+		std::ostringstream oss;
+		oss << "Hair[" << endl
+			<< "  radius = " << m_radius << endl
+			<< "]";
+		return oss.str();
+	}
+
+	MTS_DECLARE_CLASS()
+private:
+	std::vector<bool> m_startFiber;
+	std::vector<int> m_segIndex;
+	std::vector<Point> m_vertices;
+	AABB m_aabb;
+	Float m_radius;
+};
 
 MTS_IMPLEMENT_CLASS_S(Hair, false, Shape)
-MTS_EXPORT_PLUGIN(Hair, "Hair geometry");
+MTS_EXPORT_PLUGIN(Hair, "Hair intersection primitive");
 MTS_NAMESPACE_END
diff --git a/src/shapes/hair_old.cpp b/src/shapes/hair_old.cpp
new file mode 100644
index 00000000..b75137e7
--- /dev/null
+++ b/src/shapes/hair_old.cpp
@@ -0,0 +1,103 @@
+#include <fstream>
+
+#include <mitsuba/render/shape.h>
+#include <mitsuba/render/bsdf.h>
+#include <mitsuba/core/plugin.h>
+#include <mitsuba/core/fresolver.h>
+
+#include "hair.h"
+#include "miterseg.h"
+
+MTS_NAMESPACE_BEGIN
+
+Hair::Hair(const Properties &props) : Shape(props) {
+	std::string filename = props.getString("filename");
+			props.getString("filename"));
+	m_radius = (Float) props.getFloat("radius", 0.05f);
+	m_name = FileResolver::getInstance()->resolve(filename);
+
+	Log(EInfo, "Loading hair geometry from \"%s\" ..", m_name.c_str());
+
+	std::ifstream is(m_name.c_str());
+	if (is.fail())
+		Log(EError, "Could not open \"%s\"!", m_name.c_str());
+
+	std::string line;
+	bool newFiber = true;
+	Point p;
+	while (is.good()) {
+		std::getline(is, line);
+		if (line.length() > 0 && line[0] == '#')
+			continue;
+		if (line.length() == 0) {
+			newFiber = true;
+		} else {
+			std::istringstream iss(line);
+			iss >> p.x >> p.y >> p.z;
+			if (!iss.fail()) {
+				m_vertices.push_back(p);
+				m_startFiber.push_back(newFiber);
+				newFiber = false;
+			}
+		}
+	}
+	m_startFiber.push_back(true);
+
+	buildSegIndex();
+
+	Log(EDebug, "Read %i hair vertices, %i segments,", m_vertices.size(), m_segIndex.size());
+}
+
+Hair::Hair(Stream *stream, InstanceManager *manager) : Shape(stream, manager) {
+	m_radius = stream->readFloat();
+	size_t segmentCount = stream->readUInt();
+
+	m_vertices.reserve(segmentCount);
+	for (size_t i=0; i<segmentCount; ++i)
+		m_vertices.push_back(Point(stream));
+
+	m_startFiber.reserve(segmentCount+1);
+	for (size_t i=0; i<segmentCount+1; ++i)
+		m_startFiber.push_back(stream->readBool());
+
+	buildSegIndex();
+}
+
+void Hair::serialize(Stream *stream, InstanceManager *manager) const {
+	Shape::serialize(stream, manager);
+
+	stream->writeFloat(m_radius);
+	size_t segmentCount = m_vertices.size();
+	stream->writeUInt(segmentCount);
+
+	for (size_t i=0; i<segmentCount; ++i)
+		m_vertices[i].serialize(stream);
+
+	for (size_t i=0; i<segmentCount; ++i)
+		stream->writeBool(m_startFiber[i]);
+}
+
+Shape *Hair::getElement(int index) {
+	if ((size_t) index >= m_segIndex.size())
+		return NULL;
+
+	MiterHairSegment *segment = new MiterHairSegment(this, m_segIndex[index]);
+	segment->addChild("bsdf", m_bsdf);
+	segment->configure();
+	return segment;
+}
+
+
+void Hair::buildSegIndex() {
+	// Compute the index of the first vertex in each segment.
+	m_segIndex.clear();
+	for (size_t i=0; i<m_vertices.size(); i++)
+		if (!m_startFiber[i+1])
+			m_segIndex.push_back(i);
+}
+
+
+
+MTS_IMPLEMENT_CLASS_S(Hair, false, Shape)
+MTS_EXPORT_PLUGIN(Hair, "Hair geometry");
+MTS_NAMESPACE_END