X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Frender%2Fcamera.h;h=ed81a9511b3fcd9640fa4170f5adf28c23091a34;hb=9e63512930bc7dace6dc169c65161961e5dcfcf6;hp=0dd599298b3baed315f6d647cd932150feaa2511;hpb=38712d8ecc57d043a2419ffbaeeb57f7a6586f14;p=libs%2Fgl.git

diff --git a/source/render/camera.h b/source/render/camera.h
index 0dd59929..ed81a951 100644
--- a/source/render/camera.h
+++ b/source/render/camera.h
@@ -8,6 +8,20 @@
 namespace Msp {
 namespace GL {
 
+/**
+Represents a point of view in 3D space.
+
+A Camera provides two matrices.  The view matrix is the inverse of the camera's
+model matrix and transforms coordinates from world space to eye space (the
+camera's object space).  The projection matrix transforms coordinates from eye
+space to clip space. 
+
+Orientation of the Camera is determined by look direction and up direction.
+Look direction corresponds to the negative Z axis direction in eye space.  The
+YZ plane of eye space is aligned to the plane formed by the look and up
+directions.  Setting the up direction to the opposite of gravity direction is
+an easy way to keep the camera upright.
+*/
 class Camera: public Placeable
 {
 public:
@@ -47,12 +61,26 @@ private:
 public:
 	Camera();
 
+	/** Sets the camera projection to perspective, characterised by the vertical
+	field of view.  Horizontal FoV is computed with the aspect ratio. */
 	void set_field_of_view(const Geometry::Angle<float> &);
+
+	/** Sets the camera projection to orthogonal, characterized by the size of
+	the projection region. */
 	void set_orthographic(float, float);
+
 	void set_aspect_ratio(float);
 	void set_depth_clip(float, float);
+
+	/** Sets the direction of the frustum axis, which corresponds to the center
+	of the screen.  The offset is expressed in terms of the neutral frustum such
+	that -1 is the left or bottom edge and 1 is the right or top edge. */
 	void set_frustum_axis(float, float);
+
+	/** Apply a rotation to the view frustum after projection.  This can be used
+	with rotated displayes without affecting the camera's orientation. */
 	void set_frustum_rotation(const Geometry::Angle<float> &);
+
 	const Geometry::Angle<float> &get_field_of_view() const { return fov; }
 	bool is_orthographic() const { return fov==Geometry::Angle<float>::zero(); }
 	float get_orthographic_width() const { return height*aspect; }
@@ -91,6 +119,7 @@ public:
 	Vector4 unproject(const Vector4 &) const;
 	Vector3 unproject(const Vector3 &) const;
 
+	/** Returns a ProgramData object containing the camera matrices. */
 	const ProgramData &get_shader_data() const { return shdata; }
 
 private: