improved Track view

3 files changed, 38 insertions, 68 deletions

diff --git a/src/math/axis.cc b/src/math/axis.cc
index 4d752bf..aa35d92 100644
--- a/src/math/axis.cc
+++ b/src/math/axis.cc
@@ -74,6 +74,23 @@ void Axis::change_roll(const float angle) {
 	axis_vector[1].assign(up);
 }
 
+// perform a rotation about an arbitrary axis
+/* notes:
+	http://mathworld.wolfram.com/RotationFormula.html
+*/
+void Axis::rotate(Vector3f const &normal, float angle)
+{
+	float cosa = cosf(angle);
+	float sina = sinf(angle);
+
+	for (size_t i =0; i < 3; i++) {
+		axis_vector[i] = 
+			axis_vector[i]*cosa + 
+			normal * dotproduct(normal, axis_vector[i]) * (1 - cosa) + 
+			crossproduct(axis_vector[i], normal)*sina;
+	}
+}
+
 /*
 Axis const Axis::transpose()
 {
diff --git a/src/math/axis.h b/src/math/axis.h
index d011675..1422564 100644
--- a/src/math/axis.h
+++ b/src/math/axis.h
@@ -48,6 +48,9 @@ public:
 	/// change roll, rotate around forward vector (positive is left)
 	void change_roll(const float angle);
 
+	/// rotation about an arbitrary axis
+	void rotate(Vector3f const &normal, float angle);
+
 private:
 	Vector3f		axis_vector[3];
 };
diff --git a/src/render/camera.cc b/src/render/camera.cc
index e37fd0d..c35cb3c 100644
--- a/src/render/camera.cc
+++ b/src/render/camera.cc
@@ -186,79 +186,29 @@ void Camera::frame(float seconds)
 		distance = core::localcontrol()->radius();
 
 		if (mode() == Track) {
-			float cosangle;
-			float angle;
-			float side;
-			float u;
-			//const float camspeed = 90.0f * seconds; // 180 degrees per second
-
-			math::Vector3f n;
-			math::Vector3f p;
-
-			// camera axis: pitch
-
-			// project target_axis.up() into the plane with axis->left() normal
-			n = camera_axis.left();
-			p = target_axis.up();
-			u = p[0]*n[0] + p[1]*n[1] + p[2]*n[2] / (-n[0]*n[0] - n[1]*n[1] - n[2] * n[2]);
-			p = target_axis.up() + u * n;
-	
-			side = camera_axis.forward().x * p.x + 
-				camera_axis.forward().y * p.y +
-				camera_axis.forward().z * p.z;
-
-			if ((fabs(side) - MIN_DELTA > 0)) {
-				
-				cosangle = math::dotproduct(p, camera_axis.up());
-				if (fabs(cosangle) + MIN_DELTA < 1 ) {
-					angle = acos(cosangle) * 180.0f / M_PI;
-					angle = math::sgnf(side)  * angle * seconds;
-					camera_axis.change_pitch(-angle);
-				}
-			}
 
-			// camera axis: direction
-
-			// project target_axis.forward() into the plane with axis.up() normal
-			n = camera_axis.up();
-			p = target_axis.forward();
-			u = p[0]*n[0] + p[1]*n[1] + p[2]*n[2] / (-n[0]*n[0] - n[1]*n[1] - n[2] * n[2]);
-			p = target_axis.forward() + u * n;
-
-			side = camera_axis.left().x * p.x + 
-				camera_axis.left().y * p.y +
-				camera_axis.left().z * p.z;
-
-			if ((fabs(side) - MIN_DELTA > 0)) {
-				
-				cosangle = math::dotproduct(p, camera_axis.forward());
-				if (fabs(cosangle) + MIN_DELTA < 1 ) {
-					angle = acos(cosangle) * 180.0f / M_PI;
-					angle = math::sgnf(side)  * angle * seconds;
-					camera_axis.change_direction(angle);
-				}
+			float cosangle;		// cosine of an angle
+			float angle;		// angle in radians	
+			math::Vector3f n;	// normal of a plane
+
+			// camera axis: pitch & direction
+
+			n.assign(math::crossproduct(camera_axis.forward(), target_axis.forward()));
+			if (n.lengthsquared() > MIN_DELTA) {
+				n.normalize();
+				cosangle = math::dotproduct(camera_axis.forward(), target_axis.forward());
+				angle = acos(cosangle); // * 180.0f / M_PI;
+				camera_axis.rotate(n, -angle * seconds);
 			}
 
 			// camera axis: roll
 
-			// project target_axis.up() into the plane with axis.forward() normal
-			n = camera_axis.forward();
-			p = target_axis.up();
-			u = p[0]*n[0] + p[1]*n[1] + p[2]*n[2] / (-n[0]*n[0] - n[1]*n[1] - n[2] * n[2]);
-			p = target_axis.up() + u * n;
-
-			side = camera_axis.left().x * p.x + 
-				camera_axis.left().y * p.y +
-				camera_axis.left().z * p.z;
-
-			if ((fabs(side) - MIN_DELTA > 0)) {
-				
-				cosangle = math::dotproduct(p, camera_axis.up());
-				if (fabs(cosangle) + MIN_DELTA < 1 ) {
-					angle = acos(cosangle) * 180.0f / M_PI;
-					angle = math::sgnf(side)  * angle * seconds;
-					camera_axis.change_roll(angle);
-				}
+			n.assign(math::crossproduct(camera_axis.left(), target_axis.left()));
+			if (n.lengthsquared() > MIN_DELTA) {
+				n.normalize();
+				cosangle = math::dotproduct(camera_axis.left(), target_axis.left());
+				angle = acos(cosangle); // * 180.0f / M_PI;
+				camera_axis.rotate(n, -angle * seconds);
 			}
 
 			if (core::localcontrol()->model()) {