documentation updates, finished the disk shape

include/mitsuba/core/util.h

@@ -438,6 +438,9 @@ extern MTS_EXPORT_CORE Point2 squareToDisk(const Point2 &sample);
 /// Low-distortion concentric square to disk mapping by Peter Shirley (PDF: 1/(2 * PI))
 extern MTS_EXPORT_CORE Point2 squareToDiskConcentric(const Point2 &sample);
 
+/// Low-distortion concentric disk to square mapping 
+extern MTS_EXPORT_CORE Point2 diskToSquareConcentric(const Point2 &sample);
+
 /// Convert an uniformly distributed square sample into barycentric coordinates
 extern MTS_EXPORT_CORE Point2 squareToTriangle(const Point2 &sample);
 

src/libcore/util.cpp

@@ -690,6 +690,33 @@ Point2 squareToDiskConcentric(const Point2 &sample) {
 	return result*coords.x;
 }
 
+Point2 diskToSquareConcentric(const Point2 &p) {
+	Float r   = std::sqrt(p.x * p.x + p.y * p.y),
+		  phi = std::atan2(p.y, p.x),
+		  a, b;
+
+	if (phi < -M_PI/4) {
+  		/* in range [-pi/4,7pi/4] */
+		phi += 2*M_PI;
+	}
+
+	if (phi < M_PI/4) { /* region 1 */
+		a = r;
+		b = phi * a / (M_PI/4);
+	} else if (phi < 3*M_PI/4) { /* region 2 */
+		b = r;
+		a = -(phi - M_PI/2) * b / (M_PI/4);
+	} else if (phi < 5*M_PI/4) { /* region 3 */
+		a = -r;
+		b = (phi - M_PI) * a / (M_PI/4);
+	} else { /* region 4 */
+		b = -r;
+		a = -(phi - 3*M_PI/2) * b / (M_PI/4);
+	}
+
+	return Point2(0.5f * (a+1), 0.5f * (b+1));
+}
+
 Float squareToConePdf(Float cosCutoff) {
 	return 1 / (2 * M_PI * (1 - cosCutoff));
 }

src/librender/texture.cpp

@@ -45,9 +45,10 @@ Texture2D::Texture2D(const Properties &props) : Texture(props) {
 			props.getFloat("uoffset", 0.0f),
 			props.getFloat("voffset", 0.0f)
 		);
+		Float uvscale = props.getFloat("uvscale", 1.0f);
 		m_uvScale = Vector2(
-			props.getFloat("uscale", 1.0f),
-			props.getFloat("vscale", 1.0f)
+			props.getFloat("uscale", uvscale),
+			props.getFloat("vscale", uvscale)
 		);
 	} else {
 		Log(EError, "Only UV coordinates are supported at the moment!");

src/shapes/SConscript

@@ -1,8 +1,8 @@
 Import('env', 'plugins')
 
 plugins += env.SharedLibrary('obj', ['obj.cpp'])
-plugins += env.SharedLibrary('ply', ['ply/ply.cpp', 'ply/ply_parser.cpp'],
-	CPPPATH = env['CPPPATH'] + ['ply'])
+plugins += env.SharedLibrary('ply', ['ply.cpp', 'ply/ply_parser.cpp'],
+	CPPPATH = env['CPPPATH'] + ['#src/shapes'])
 plugins += env.SharedLibrary('serialized', ['serialized.cpp'])
 plugins += env.SharedLibrary('rectangle', ['rectangle.cpp'])
 plugins += env.SharedLibrary('disk', ['disk.cpp'])

src/shapes/animatedinstance.cpp

@@ -24,7 +24,7 @@
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{animatedinstance}{Animated geometry instance}
- * \order{6}
+ * \order{10}
  * \parameters{
  *     \parameter{filename}{\String}{Filename of an animated
  *     transformation}

src/shapes/disk.cpp

@@ -0,0 +1,255 @@
+/*
+    This file is part of Mitsuba, a physically based rendering system.
+
+    Copyright (c) 2007-2011 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/render/luminaire.h>
+#include <mitsuba/render/subsurface.h>
+#include <mitsuba/render/trimesh.h>
+#include <mitsuba/core/properties.h>
+
+MTS_NAMESPACE_BEGIN
+
+/*!\plugin{disk}{Disk intersection primitive}
+ * \order{4}
+ * \parameters{
+ *     \parameter{toWorld}{\Transform}{
+ *	      Specifies a linear object-to-world transformation.
+ *        Note that non-uniform scales are not permitted!
+ *        \default{none (i.e. object space $=$ world space)}
+ *     }
+ *     \parameter{flipNormals}{\Boolean}{
+ *	      Is the disk inverted, i.e. should the normal vectors
+ *		  be flipped? \default{\code{false}}
+ *	   }
+ *     \vspace{-8mm}
+ * }
+ * \renderings{
+ *     \rendering{Rendering with an disk emitter and a textured disk, showing
+ *     the default parameterization. (\lstref{disk})}{shape_disk}
+ * }
+ * 
+ * \vspace{-1mm}
+ * This shape plugin describes a simple disk intersection primitive. It is
+ * usually preferable over discrete approximations made from triangles.
+ *
+ * By default, the disk has unit radius and is located at the origin. Its
+ * surface normal points into the positive $Z$ direction.
+ * To change the disk scale, rotation, or translation, use the 
+ * \code{toWorld} parameter.
+ *
+ * \begin{xml}[caption={A simple example involving two disk instances}, label=lst:disk]
+ * <scene version="0.3.0">
+ *     <shape type="disk">
+ *         <bsdf type="diffuse">
+ *             <texture name="reflectance" type="checkerboard">
+ *                 <float name="uvscale" value="5"/>
+ *             </texture>
+ *         </bsdf>
+ *     </shape>
+ *     <shape type="disk">
+ *         <transform name="toWorld">
+ *             <rotate x="1" angle="90"/>
+ *             <scale value="0.3"/>
+ *             <translate y="1" z="0.3"/>
+ *         </transform>
+ *         <luminaire type="area">
+ *             <spectrum name="intensity" value="4"/>
+ *         </luminaire>
+ *     </shape>
+ * </scene>
+ * \end{xml}
+ */
+class Disk : public Shape {
+public:
+	Disk(const Properties &props) : Shape(props) {
+		m_objectToWorld = props.getTransform("toWorld", Transform());
+		if (props.getBoolean("flipNormals", false))
+			m_objectToWorld = m_objectToWorld * Transform::scale(Vector(1, 1, -1));
+		m_worldToObject = m_objectToWorld.inverse();
+	}
+
+	Disk(Stream *stream, InstanceManager *manager) 
+			: Shape(stream, manager) {
+		m_objectToWorld = Transform(stream);
+		m_worldToObject = m_objectToWorld.inverse();
+		configure();
+	}
+
+	void serialize(Stream *stream, InstanceManager *manager) const {
+		Shape::serialize(stream, manager);
+		m_objectToWorld.serialize(stream);
+	}
+
+	void configure() {
+		Shape::configure();
+
+		m_normal = normalize(m_objectToWorld(Normal(0, 0, 1)));
+
+		Vector dpdu = m_objectToWorld(Vector(1, 0, 0));
+		Vector dpdv = m_objectToWorld(Vector(0, 1, 0));
+
+		if (std::abs(dot(dpdu, dpdv)) > Epsilon)
+			Log(EError, "Error: 'toWorld' transformation contains shear!");
+
+		if (std::abs(dpdu.length() / dpdv.length() - 1) > Epsilon)
+			Log(EError, "Error: 'toWorld' transformation contains a non-uniform scale!");
+
+		m_surfaceArea = M_PI * dpdu.length() * dpdu.length();
+	}
+
+	AABB getAABB() const {
+		AABB aabb;
+		aabb.expandBy(m_objectToWorld(Point( 1,  0, 0)));
+		aabb.expandBy(m_objectToWorld(Point(-1,  0, 0)));
+		aabb.expandBy(m_objectToWorld(Point( 0,  1, 0)));
+		aabb.expandBy(m_objectToWorld(Point( 0, -1, 0)));
+		return aabb;
+	}
+
+	Float getSurfaceArea() const {
+		return m_surfaceArea;
+	}
+
+	inline bool rayIntersect(const Ray &_ray, Float mint, Float maxt, Float &t, void *temp) const {
+		Ray ray;
+		m_worldToObject.transformAffine(_ray, ray);
+		Float hit = -ray.o.z/ray.d.z;
+
+		if (hit < mint || hit > maxt)
+			return false;
+
+		Point local = ray(hit);
+
+		if (local.x * local.x + local.y * local.y > 1)
+			return false;
+
+		t = hit;
+
+		if (temp) {
+			Float *data = static_cast<Float *>(temp);
+			data[0] = local.x;
+			data[1] = local.y;
+		}
+
+		return true;
+	}
+
+	bool rayIntersect(const Ray &ray, Float mint, Float maxt) const {
+		Float t;
+		return Disk::rayIntersect(ray, mint, maxt, t, NULL);
+	}
+
+	void fillIntersectionRecord(const Ray &ray, 
+			const void *temp, Intersection &its) const {
+		const Float *data = static_cast<const Float *>(temp);
+
+		Float r = std::sqrt(data[0] * data[0] + data[1] * data[1]),
+			  invR = (r == 0) ? 0.0f : (1.0f / r);
+
+		Float phi = std::atan2(data[1], data[0]);
+		if (phi < 0)
+			phi += 2*M_PI;
+
+		Float cosPhi = data[0] * invR, sinPhi = data[1] * invR;
+
+		its.dpdu = m_objectToWorld(Vector(cosPhi, sinPhi, 0));
+		its.dpdv = m_objectToWorld(Vector(-sinPhi, cosPhi, 0));
+
+		its.shFrame = its.geoFrame = Frame(
+			normalize(its.dpdu), normalize(its.dpdv), m_normal);
+		its.uv = Point2(r, phi * INV_TWOPI);
+		its.p = ray(its.t);
+		its.wi = its.toLocal(-ray.d);
+		its.shape = this;
+ 		its.hasUVPartials = false;
+	}
+
+	ref<TriMesh> createTriMesh() {
+		const unsigned int phiSteps = 40;
+
+		ref<TriMesh> mesh = new TriMesh(getName(),
+			phiSteps-1, 2*phiSteps, true, true, false);
+
+		Point *vertices = mesh->getVertexPositions();
+		Normal *normals = mesh->getVertexNormals();
+		Point2 *texcoords = mesh->getVertexTexcoords();
+		Triangle *triangles = mesh->getTriangles();
+
+		Float dphi = (2 * M_PI) / (Float) (phiSteps-1);
+
+		Point center = m_objectToWorld(Point(0.0f));
+		for (size_t i=0; i<phiSteps; ++i) {
+			Float phi = i*dphi;
+			vertices[i] = center;
+			vertices[phiSteps+i] = m_objectToWorld(
+				Point(std::cos(phi), std::sin(phi), 0)
+			);
+
+			normals[i] = m_normal;
+			normals[phiSteps+i] = m_normal;
+			texcoords[i] = Point2(0.0f, phi * INV_TWOPI);
+			texcoords[phiSteps+i] = Point2(1.0f, phi * INV_TWOPI);
+		}
+
+		for (size_t i=0; i<phiSteps-1; ++i) {
+			triangles[i].idx[0] = i;
+			triangles[i].idx[1] = i+phiSteps;
+			triangles[i].idx[2] = i+phiSteps+1;
+		}
+
+		mesh->setBSDF(m_bsdf);
+		mesh->setLuminaire(m_luminaire);
+		mesh->configure();
+
+		return mesh.get();
+	}
+
+	std::string toString() const {
+		std::ostringstream oss;
+		oss << "Disk[" << endl
+			<< "  objectToWorld = " << indent(m_objectToWorld.toString()) << ", " << endl
+			<< "  bsdf = " << indent(m_bsdf.toString()) << "," << endl
+			<< "  luminaire = " << indent(m_luminaire.toString()) << "," << endl
+			<< "  subsurface = " << indent(m_subsurface.toString()) << endl
+			<< "]";
+		return oss.str();
+	}
+
+	Float sampleArea(ShapeSamplingRecord &sRec, const Point2 &sample) const {
+		sRec.n = m_normal;
+		Point2 p = squareToDiskConcentric(sample);
+		sRec.p = m_objectToWorld(Point3(p.x, p.y, 0));
+		return 1.0f / m_surfaceArea;
+	}
+
+	Float pdfArea(const ShapeSamplingRecord &sRec) const {
+		return 1.0f / m_surfaceArea;
+	}
+
+	MTS_DECLARE_CLASS()
+private:
+	Transform m_objectToWorld;
+	Transform m_worldToObject;
+	Normal m_normal;
+	Float m_surfaceArea;
+};
+
+MTS_IMPLEMENT_CLASS_S(Disk, false, Shape)
+MTS_EXPORT_PLUGIN(Disk, "Disk intersection primitive");
+MTS_NAMESPACE_END

src/shapes/hair.cpp

@@ -31,6 +31,7 @@
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{hair}{Hair intersection shape}
+ * \order{7}
  * \parameters{
  *     \parameter{filename}{\String}{
  *	     Filename of the hair data file that should be loaded

src/shapes/instance.cpp

@@ -21,7 +21,7 @@
 MTS_NAMESPACE_BEGIN
  
 /*!\plugin{instance}{Geometry instance}
- * \order{6}
+ * \order{9}
  * \parameters{
  *     \parameter{\Unnamed}{\ShapeGroup}{A reference to a 
  *     shape group that should be instantiated}

src/shapes/obj.cpp

@@ -29,7 +29,7 @@
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{obj}{Wavefront OBJ mesh loader}
- * \order{3}
+ * \order{5}
  * \parameters{
  *     \parameter{filename}{\String}{
  *	     Filename of the OBJ file that should be loaded

src/shapes/ply.cpp

@@ -38,7 +38,7 @@ using namespace std::tr1::placeholders;
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{ply}{PLY (Stanford Triangle Format) mesh loader}
- * \order{4}
+ * \order{6}
  * \parameters{
  *     \parameter{filename}{\String}{
  *	     Filename of the PLY file that should be loaded

src/shapes/rectangle.cpp

@@ -26,9 +26,11 @@
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{rectangle}{Rectangle intersection primitive}
+ * \order{3}
  * \parameters{
  *     \parameter{toWorld}{\Transform}{
  *	      Specifies a linear object-to-world transformation.
+ *        It is allowed to use non-uniform scaling, but no shear.
  *        \default{none (i.e. object space $=$ world space)}
  *     }
  *     \parameter{flipNormals}{\Boolean}{
@@ -57,7 +59,6 @@ MTS_NAMESPACE_BEGIN
  *     <shape type="rectangle">
  *         <bsdf type="diffuse"/>
  *     </shape>
- *
  *     <shape type="rectangle">
  *         <transform name="toWorld">
  *             <rotate x="1" angle="90"/>
@@ -152,6 +153,8 @@ public:
 			const void *temp, Intersection &its) const {
 		const Float *data = static_cast<const Float *>(temp);
 		its.shFrame = its.geoFrame = m_frame;
+		its.dpdu = m_dpdu;
+		its.dpdv = m_dpdv;
 		its.uv = Point2(0.5f * (data[0]+1), 0.5f * (data[1]+1));
 		its.p = ray(its.t);
 		its.wi = its.toLocal(-ray.d);

src/shapes/serialized.cpp

@@ -24,6 +24,7 @@
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{serialized}{Serialized mesh loader}
+ * \order{11}
  * \parameters{
  *     \parameter{filename}{\String}{
  *	     Filename of the gemoetry file that should be loaded
@@ -44,7 +45,7 @@ MTS_NAMESPACE_BEGIN
  * }
  * This plugin represents the most space and time-efficient way
  * of getting geometry into Mitsuba. It uses a highly efficient
- * lossless compressed format for geometry storage. Th format will
+ * lossless compressed format for geometry storage. The format will
  * be explained on this page in a subsequent revision of the
  * documentation.
  */

src/shapes/shapegroup.cpp

@@ -21,7 +21,7 @@
 MTS_NAMESPACE_BEGIN
 
 /*!\plugin{shapegroup}{Shape group for geometry instancing}
- * \order{5}
+ * \order{8}
  * \parameters{
  *     \parameter{\Unnamed}{\Shape}{One or more shapes that should be
  *         made available for geometry instancing}