rcCompactHeightfield Struct Reference

A compact, static heightfield representing unobstructed space. More...

#include <Recast.h>

Public Attributes
int	width
	The width of the heightfield. (Along the x-axis in cell units.) More...
int	height
	The height of the heightfield. (Along the z-axis in cell units.) More...
int	spanCount
	The number of spans in the heightfield. More...
int	walkableHeight
	The walkable height used during the build of the field. (See: rcConfig::walkableHeight) More...
int	walkableClimb
	The walkable climb used during the build of the field. (See: rcConfig::walkableClimb) More...
int	borderSize
	The AABB border size used during the build of the field. (See: rcConfig::borderSize) More...
unsigned short	maxDistance
	The maximum distance value of any span within the field. More...
unsigned short	maxRegions
	The maximum region id of any span within the field. More...
float	bmin [3]
	The minimum bounds in world space. [(x, y, z)]. More...
float	bmax [3]
	The maximum bounds in world space. [(x, y, z)]. More...
float	cs
	The size of each cell. (On the xz-plane.) More...
float	ch
	The height of each cell. (The minimum increment along the y-axis.) More...
rcCompactCell *	cells
	Array of cells. [Size: width*height]. More...
rcCompactSpan *	spans
	Array of spans. [Size: spanCount]. More...
unsigned short *	dist
	Array containing border distance data. [Size: spanCount]. More...
navAreaMask *	areaMasks
	Array containing area id data. [Size: spanCount]. More...

Description

A compact, static heightfield representing unobstructed space.

For this type of heightfield, the spans represent the open (unobstructed) space above the solid surfaces of a voxel field. It is usually created from a rcHeightfield object. Data is stored in a compact, efficient manner, but the structure is not condusive to adding and removing spans.

The standard process for buidling a compact heightfield is to allocate it using rcAllocCompactHeightfield, build it using rcBuildCompactHeightfield, then run it through the various helper functions to generate neighbor and region data.

Connected neighbor spans form non-overlapping surfaces. When neighbor information is generated, spans will include data that can be used to locate axis-neighbors. Axis-neighbors are connected spans that are offset from the current cell column as follows:

Direction 0 = (-1, 0)
Direction 1 = (0, 1)
Direction 2 = (1, 0)
Direction 3 = (0, -1)

Example of iterating and inspecting spans, including connected neighbors:

// Where chf is an instance of a rcCompactHeightfield.

const float cs = chf.cs;
const float ch = chf.ch;

for (int y = 0; y < chf.height; ++y)
{
    for (int x = 0; x < chf.width; ++x)
    {
        // Deriving the minimum corner of the grid location.
        const float fx = chf.bmin[0] + x*cs;
        const float fz = chf.bmin[2] + y*cs;

        // Get the cell for the grid location then iterate
        // up the column.
        const rcCompactCell& c = chf.cells[x+y*chf.width];
        for (unsigned i = c.index, ni = c.index+c.count; i < ni; ++i)
        {
            const rcCompactSpan& s = chf.spans[i];

            Deriving the minimum (floor) of the span.
            const float fy = chf.bmin[1] + (s.y+1)*ch;

            // Testing the area assignment of the span.
            if (chf.areas[i] == RC_WALKABLE_AREA)
            { 
                // The span is in the default 'walkable area'.
            }
            else if (chf.areas[i] == RC_NULL_AREA)
            { 
                // The surface is not considered walkable.
                // E.g. It was filtered out during the build processes.
            }
            else
            { 
                // Do something. (Only applicable for custom build
                // build processes.)
            }

            // Iterating the connected axis-neighbor spans.
            for (int dir = 0; dir < 4; ++dir)
            {
                if (rcGetCon(s, dir) != RC_NOT_CONNECTED)
                {
                    // There is a neighbor in this direction.
                    const int nx = x + rcGetDirOffsetX(dir);
                    const int ny = y + rcGetDirOffsetY(dir);
                    const int ni = (int)chf.cells[nx+ny*w].index + rcGetCon(s, 0);
                    const rcCompactSpan& ns = chf.spans[ni];
                    // Do something with the neighbor span.
                }
            }
        }
    }
}

See also

rcAllocCompactHeightfield, rcFreeCompactHeightfield, rcBuildCompactHeightfield

Member Data Documentation

navAreaMask* rcCompactHeightfield::areaMasks

Array containing area id data. [Size: spanCount].

float rcCompactHeightfield::bmax[3]

The maximum bounds in world space. [(x, y, z)].

float rcCompactHeightfield::bmin[3]

The minimum bounds in world space. [(x, y, z)].

int rcCompactHeightfield::borderSize

The AABB border size used during the build of the field. (See: rcConfig::borderSize)

rcCompactCell* rcCompactHeightfield::cells

Array of cells. [Size: width*height].

float rcCompactHeightfield::ch

The height of each cell. (The minimum increment along the y-axis.)

float rcCompactHeightfield::cs

The size of each cell. (On the xz-plane.)

unsigned short* rcCompactHeightfield::dist

Array containing border distance data. [Size: spanCount].

int rcCompactHeightfield::height

The height of the heightfield. (Along the z-axis in cell units.)

unsigned short rcCompactHeightfield::maxDistance

The maximum distance value of any span within the field.

unsigned short rcCompactHeightfield::maxRegions

The maximum region id of any span within the field.

int rcCompactHeightfield::spanCount

The number of spans in the heightfield.

rcCompactSpan* rcCompactHeightfield::spans

Array of spans. [Size: spanCount].

int rcCompactHeightfield::walkableClimb

The walkable climb used during the build of the field. (See: rcConfig::walkableClimb)

int rcCompactHeightfield::walkableHeight

The walkable height used during the build of the field. (See: rcConfig::walkableHeight)

int rcCompactHeightfield::width

The width of the heightfield. (Along the x-axis in cell units.)

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

• Recast.h