rcHeightfield Struct Reference

A dynamic heightfield representing obstructed 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...
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...
rcSpan **	spans
	Heightfield of spans (width*height). More...
rcSpanPool *	pools
	Linked list of span pools. More...
rcSpan *	freelist
	The next free span. More...

Description

A dynamic heightfield representing obstructed space.

The grid of a heightfield is layed out on the xz-plane based on the value of cs. Spans exist within the grid columns with the span min/max values at increments of ch from the base of the grid. The smallest possible span size is (cs width) * (cs depth) * (ch height). (Which is a single voxel.)

The standard process for buidling a heightfield is to allocate it using rcAllocHeightfield, initialize it using rcCreateHeightfield, then add spans using the various helper functions such as rcRasterizeTriangle.

Building a heightfield is one of the first steps in creating a polygon mesh from source geometry. After it is populated, it is used to build a rcCompactHeightfield.

Example of iterating the spans in a heightfield:

// Where hf is a reference to an heightfield object.

const float* orig = hf.bmin;
const float cs = hf.cs;
const float ch = hf.ch;

const int w = hf.width;
const int h = hf.height;

for (int y = 0; y < h; ++y)
{
    for (int x = 0; x < w; ++x)
    {
        // Deriving the minimum corner of the grid location.
        float fx = orig[0] + x*cs;
        float fz = orig[2] + y*cs;
        // The base span in the column. (May be null.)
        const rcSpan* s = hf.spans[x + y*w]; 
        while (s)
        {
            // Detriving the minium and maximum world position of the span.
            float fymin = orig[1]+s->smin*ch;
            float fymax = orig[1] + s->smax*ch;
            // Do other things with the span before moving up the column.
            s = s->next;
        }
    }
}

See also

rcAllocHeightfield, rcFreeHeightField, rcCreateHeightfield

Member Data Documentation

float rcHeightfield::bmax[3]

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

float rcHeightfield::bmin[3]

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

float rcHeightfield::ch

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

float rcHeightfield::cs

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

rcSpan* rcHeightfield::freelist

The next free span.

int rcHeightfield::height

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

rcSpanPool* rcHeightfield::pools

Linked list of span pools.

rcSpan** rcHeightfield::spans

Heightfield of spans (width*height).

int rcHeightfield::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