typedef struct _RoamTriangle RoamTriangle;
typedef struct _RoamDiamond RoamDiamond;
typedef struct _RoamSphere RoamSphere;
+/**
+ * RoamHeightFunc:
+ * @lat: the latitude
+ * @lon: the longitude
+ * @user_data: user data passed to the function
+ *
+ * See #GisHeightFunc
+ *
+ * Returns: the elevation
+ */
typedef gdouble (*RoamHeightFunc)(gdouble lat, gdouble lon, gpointer user_data);
/* Misc */
+/**
+ * RoamView:
+ * @model: model view matrix
+ * @proj: projection matrix
+ * @view: viewport matrix
+ * @version: version
+ *
+ * Stores projection matrices
+ */
struct _RoamView {
gdouble model[16];
gdouble proj[16];
/*************
* RoamPoint *
*************/
+/**
+ * RoamPoint:
+ *
+ * Points are used as vertices for triangles. A single point my be shared among
+ * several triangles in order to conceive space and avoid recalculating
+ * projections. Points also store a lot of cached data. The normal vertex normal
+ * is the averaged surface normal of each associated triangle.
+ */
struct _RoamPoint {
/*< private >*/
gdouble x, y, z; /* Model coordinates */
/****************
* RoamTriangle *
****************/
+/**
+ * RoamTriangle:
+ *
+ * Triangles are one of the key datatypes in ROAM. The surface is made up of
+ * triangles. Each triangle has an associated "error". When the surface is being
+ * updated after the view changes, each triangles error is updated. Afterwards
+ * the triangles with the most error are split int to triangles, each with a
+ * lower error than the original.
+ *
+ * Triangles store a lot of data about their location in the mesh so that they
+ * can be split and merged (unsplit) without having to recreate the mesh.
+ */
struct _RoamTriangle {
/*< private >*/
/* Left, middle and right vertices */
/* Left, base, and right neighbor triangles */
struct { RoamTriangle *l,*b,*r; } t;
- RoamPoint *split; /* Split point */
- RoamDiamond *parent; /* Parent diamond */
- double norm[3]; /* Surface normal */
- double error; /* Screen space error */
+ RoamPoint *split; /* Split point */
+ RoamDiamond *parent; /* Parent diamond */
+ RoamTriangle *kids[2]; /* Higher-res triangles */
+ double norm[3]; /* Surface normal */
+ double error; /* Screen space error */
GPQueueHandle handle;
/* For get_intersect */
struct { gdouble n,s,e,w; } edge;
- RoamTriangle *kids[2];
};
-RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r);
+RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r,
+ RoamDiamond *parent);
void roam_triangle_free(RoamTriangle *triangle);
void roam_triangle_add(RoamTriangle *triangle,
RoamTriangle *left, RoamTriangle *base, RoamTriangle *right,
/***************
* RoamDiamond *
***************/
+/**
+ * RoamDiamond:
+ *
+ * When two adjacent triangles are split, they, along with the four new child
+ * triangles, are added to a diamond which keeps track of them.
+ *
+ * Like triangles, diamond have an error associated with it. However, when a
+ * diamonds error is small enough it is "merged". That is, the diamond along
+ * with the child triangles is removed and the original two triangles triangles
+ * are added back into the mesh.
+ */
struct _RoamDiamond {
/*< private >*/
- RoamTriangle *kids[4]; /* Child triangles */
RoamTriangle *parents[2]; /* Parent triangles */
double error; /* Screen space error */
gboolean active; /* For internal use */
GPQueueHandle handle;
};
-RoamDiamond *roam_diamond_new(
- RoamTriangle *parent0, RoamTriangle *parent1,
- RoamTriangle *kid0, RoamTriangle *kid1,
- RoamTriangle *kid2, RoamTriangle *kid3);
+RoamDiamond *roam_diamond_new(RoamTriangle *parent0, RoamTriangle *parent1);
void roam_diamond_add(RoamDiamond *diamond, RoamSphere *sphere);
void roam_diamond_remove(RoamDiamond *diamond, RoamSphere *sphere);
void roam_diamond_merge(RoamDiamond *diamond, RoamSphere *sphere);
/**************
* RoamSphere *
**************/
+/**
+ * RoamSphere:
+ *
+ * The sphere keeps track of the triangles and diamonds in the mesh.
+ *
+ * Originally the sphere consists of only 8 triangles forming a octahedron.
+ * These triangles are quickly split to create a smoother sphere.
+ */
struct _RoamSphere {
/*< private >*/
GPQueue *triangles; /* List of triangles */