qaf::Geom Class Reference

#include <qafGeom.h>

List of all members.

---

Detailed Description

Provides static methods for useful geometric operations.

Static Public Member Functions
static bool	segmentIntersection (float s1x1, float s1y1, float s1x2, float s1y2, float s2x1, float s2y1, float s2x2, float s2y2, Vector2D *point=NULL)
	Tests for segment intersection.
static int	segmentCircleIntersection (float xCenter, float yCenter, float radius, float x1, float y1, float x2, float y2, Vector2D *pvIntPoint1=NULL, Vector2D *pvIntPoint2=NULL)
	Tests if a segment is intersecting a circle.
static void	renderCircle (float xCenter, float yCenter, float radius, unsigned int color)
	Renders a circle as a series of lines.
static float	invSqrt (float x)
	The infamous "fast inverse square root" function.
static void	clipPolygon (Container< Vector2D > *poly, const Vector2D &planeP, const Vector2D &planeN)
	Clips the polygon so it will be contained within a semiplane.
static bool	insidePolygon (const Vector2D &p, const Vector2D *points, int nPoints)
	Given the polygon described by points, returns true if the point p lies inside it.
static bool	insidePolygon (const Vector2D &p, const Container< Vector2D > &points)
	Given the polygon described by points, returns true if the point p lies inside it.
static void	renderPolygon (const Vector2D *points, int nPoints, float translateX, float translateY, unsigned long color)
	Renders the specified polygon as a set of lines in the specified color, translated as requested.
static void	renderPolygon (const Container< Vector2D > &points, float translateX, float translateY, unsigned long color)
	Renders the specified polygon as a set of lines in the specified color, translated as requested.

---

Member Function Documentation

static bool qaf::Geom::segmentIntersection	(	float	s1x1,
		float	s1y1,
		float	s1x2,
		float	s1y2,
		float	s2x1,
		float	s2y1,
		float	s2x2,
		float	s2y2,
		Vector2D *	point = NULL
	)			[static]

Tests for segment intersection.

Stores the intersection point, if any, in the "point" vector, if it is not NULL.

Based on the algorithms seen here: http://www.geometryalgorithms.com/Archive/algorithm_0108/algorithm_0108.htm

Returns:

true if the two segments intersect each other

static bool qaf::Geom::insidePolygon	(	const Vector2D &	p,
		const Vector2D *	points,
		int	nPoints
	)			[static]

Given the polygon described by points, returns true if the point p lies inside it.

Based on the code seen here: http://astronomy.swin.edu.au/~pbourke/geometry/insidepoly/

static bool qaf::Geom::insidePolygon	(	const Vector2D &	p,
		const Container< Vector2D > &	points
	)			[inline, static]

Given the polygon described by points, returns true if the point p lies inside it.

Based on the code seen here: http://astronomy.swin.edu.au/~pbourke/geometry/insidepoly/

static int qaf::Geom::segmentCircleIntersection	(	float	xCenter,
		float	yCenter,
		float	radius,
		float	x1,
		float	y1,
		float	x2,
		float	y2,
		Vector2D *	pvIntPoint1 = NULL,
		Vector2D *	pvIntPoint2 = NULL
	)			[static]

Tests if a segment is intersecting a circle.

This will not detect a collision if the segment is completely contained in the circle.

There are three possible outcomes:

• The segment does not intersect the circle. The method returns zero; intPoint1 and intPoint2 are left unchanged.
• The segment intersects the circle at just one point. The method returns 1; if pvIntPoint1 is not NULL, the intersection point will be stored there.
• The segment intersects the circle at two points. The method returns 2; if pvIntPoint1 and pvIntPoint2 are not NULL, the intersection points will be stored there.

Parameters:

	xCenter	X coordinate of the circle's center.
	yCenter	Y coordinate of the circle's center.
	radius	Circle's radius.
	x1	X coordinate of the segment's first point.
	y1	Y coordinate of the segment's first point.
	x2	X coordinate of the segment's second point.
	y2	Y coordinate of the segment's second point.
	pvIntPoint1	Return value of the first intersection point.
	pvIntPoint2	Return value of the second intersection point.

static void qaf::Geom::renderCircle	(	float	xCenter,
		float	yCenter,
		float	radius,
		unsigned int	color
	)			[static]

Renders a circle as a series of lines.

The method attempts to adapt the number of segments to the size of the circle so it will not appear too fragmented.

static void qaf::Geom::clipPolygon	(	Container< Vector2D > *	poly,
		const Vector2D &	planeP,
		const Vector2D &	planeN
	)			[static]

Clips the polygon so it will be contained within a semiplane.

Parameters:

	poly	The polygon to be clipped. The resulting (clipped) polygon will be stored here as well.
	planeP	A point determining the clipping plane's position.
	planeD	The clipping plane's normal, pointing towards the interior of the clipping region.

---

The documentation for this class was generated from the following file:

• qafGeom.h

---