First Commit

For Azeroth!

dep/g3dlite/source/Capsule.cpp

@@ -0,0 +1,179 @@
+/**
+ @file Capsule.cpp
+  
+ @maintainer Morgan McGuire, http://graphics.cs.williams.edu
+
+ @created 2003-02-07
+ @edited  2005-08-18
+
+ Copyright 2000-2009, Morgan McGuire.
+ All rights reserved.
+ */
+
+#include "G3D/Capsule.h"
+#include "G3D/BinaryInput.h"
+#include "G3D/BinaryOutput.h"
+#include "G3D/LineSegment.h"
+#include "G3D/Sphere.h"
+#include "G3D/CoordinateFrame.h"
+#include "G3D/Line.h"
+#include "G3D/AABox.h"
+
+namespace G3D {
+
+Capsule::Capsule(class BinaryInput& b) {
+	deserialize(b);
+}
+
+
+Capsule::Capsule() {
+}
+
+
+Capsule::Capsule(const Vector3& _p1, const Vector3& _p2, float _r) 
+	: p1(_p1), p2(_p2), _radius(_r) {
+}
+
+
+void Capsule::serialize(class BinaryOutput& b) const {
+	p1.serialize(b);
+	p2.serialize(b);
+	b.writeFloat64(_radius);
+}
+
+
+void Capsule::deserialize(class BinaryInput& b) {
+	p1.deserialize(b);
+	p2.deserialize(b);
+	_radius = b.readFloat64();
+}
+
+
+Line Capsule::axis() const {
+	return Line::fromTwoPoints(p1, p2);
+}
+
+
+float Capsule::volume() const {
+	return 
+		// Sphere volume
+		pow(_radius, 3) * pi() * 4 / 3 +
+
+		// Cylinder volume
+		pow(_radius, 2) * (p1 - p2).magnitude();
+}
+
+
+float Capsule::area() const {
+
+	return
+		// Sphere area
+		pow(_radius, 2) * 4 * pi() +
+
+		// Cylinder area
+		twoPi() * _radius * (p1 - p2).magnitude();
+}
+
+
+void Capsule::getBounds(AABox& out) const {
+    Vector3 min = p1.min(p2) - (Vector3(1, 1, 1) * _radius);
+    Vector3 max = p1.max(p2) + (Vector3(1, 1, 1) * _radius);
+
+    out = AABox(min, max);
+}
+
+
+bool Capsule::contains(const Vector3& p) const { 
+    return LineSegment::fromTwoPoints(p1, p2).distanceSquared(p) <= square(radius());
+}
+
+
+void Capsule::getRandomSurfacePoint(Vector3& p, Vector3& N) const {
+    float h = height();
+    float r = radius();
+
+    // Create a random point on a standard capsule and then rotate to the global frame.
+
+    // Relative areas
+    float capRelArea  = sqrt(r) / 2.0f;
+    float sideRelArea = r * h;
+
+    float r1 = uniformRandom(0, capRelArea * 2 + sideRelArea);
+
+    if (r1 < capRelArea * 2) {
+
+        // Select a point uniformly at random on a sphere
+        N = Sphere(Vector3::zero(), 1).randomSurfacePoint();
+        p = N * r;
+        p.y += sign(p.y) * h / 2.0f;
+    } else {
+        // Side
+        float a = uniformRandom(0, (float)twoPi());
+        N.x = cos(a);
+        N.y = 0;
+        N.z = sin(a);
+        p.x = N.x * r;
+        p.z = N.y * r;
+        p.y = uniformRandom(-h / 2.0f, h / 2.0f);
+    }
+
+    // Transform to world space
+    CoordinateFrame cframe;
+    getReferenceFrame(cframe);
+    
+    p = cframe.pointToWorldSpace(p);
+    N = cframe.normalToWorldSpace(N);
+}
+
+
+void Capsule::getReferenceFrame(CoordinateFrame& cframe) const {
+    cframe.translation = center();
+
+    Vector3 Y = (p1 - p2).direction();
+    Vector3 X = (abs(Y.dot(Vector3::unitX())) > 0.9) ? Vector3::unitY() : Vector3::unitX();
+    Vector3 Z = X.cross(Y).direction();
+    X = Y.cross(Z);        
+    cframe.rotation.setColumn(0, X);
+    cframe.rotation.setColumn(1, Y);
+    cframe.rotation.setColumn(2, Z);
+}
+
+
+Vector3 Capsule::randomInteriorPoint() const {
+    float h = height();
+    float r = radius();
+
+    // Create a random point in a standard capsule and then rotate to the global frame.
+
+    Vector3 p;
+
+    float hemiVolume = pi() * (r*r*r) * 4 / 6.0;
+    float cylVolume = pi() * square(r) * h;
+    
+    float r1 = uniformRandom(0, 2.0 * hemiVolume + cylVolume);
+
+    if (r1 < 2.0 * hemiVolume) {
+
+        p = Sphere(Vector3::zero(), r).randomInteriorPoint();
+
+        p.y += sign(p.y) * h / 2.0f;
+
+    } else {
+
+        // Select a point uniformly at random on a disk
+        float a = uniformRandom(0, (float)twoPi());
+        float r2 = sqrt(uniformRandom(0, 1)) * r;
+
+        p = Vector3(cos(a) * r2,
+                    uniformRandom(-h / 2.0f, h / 2.0f),
+                    sin(a) * r2);
+    }
+
+    // Transform to world space
+    CoordinateFrame cframe;
+    getReferenceFrame(cframe);
+    
+    return cframe.pointToWorldSpace(p);
+}
+
+} // namespace