Irrlicht 3D Engine: irr::scene::ITerrainSceneNode Class Reference

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Public Member Functions
irr::scene::ITerrainSceneNode Class Reference

A scene node for displaying terrain using the geo mip map algorithm. More...

`#include <ITerrainSceneNode.h>`

Inheritance diagram for irr::scene::ITerrainSceneNode:

List of all members.

## Public Member Functions

- ITerrainSceneNode (ISceneNode *parent, ISceneManager *mgr, s32 id, const core::vector3df &position=core::vector3df(0.0f, 0.0f, 0.0f), const core::vector3df &rotation=core::vector3df(0.0f, 0.0f, 0.0f), const core::vector3df &scale=core::vector3df(1.0f, 1.0f, 1.0f))
    Constructor.
- virtual const core::aabbox3d
  < f32 > & getBoundingBox () const =0
    Get the bounding box of the terrain.
- virtual const core::aabbox3d
  < f32 > & getBoundingBox (s32 patchX, s32 patchZ) const =0
    Get the bounding box of a patch.
- virtual s32 getCurrentLODOfPatches (core::array< s32 > &LODs) const =0
    Populates an array with the CurrentLOD of each patch.
- virtual f32 getHeight (f32 x, f32 y) const =0
    Get height of a point of the terrain.
- virtual u32 getIndexCount () const =0
    Get the number of indices currently in the meshbuffer.
- virtual s32 getIndicesForPatch (core::array< u32 > &indices, s32 patchX, s32 patchZ, s32 LOD=0)=0
    Gets the indices for a specified patch at a specified Level of Detail.
- virtual IMesh * getMesh ()=0
    Get pointer to the mesh.
- virtual void getMeshBufferForLOD (IDynamicMeshBuffer &mb, s32 LOD=0) const =0
    Gets the meshbuffer data based on a specified level of detail.
- virtual IMeshBuffer * getRenderBuffer ()=0
    Get pointer to the buffer used by the terrain (most users will not need this)
- virtual const core::vector3df & getTerrainCenter () const =0
    Get center of terrain.
- virtual bool loadHeightMap (io::IReadFile *file, video::SColor vertexColor=video::SColor(255, 255, 255, 255), s32 smoothFactor=0)=0
    Initializes the terrain data. Loads the vertices from the heightMapFile.
- virtual bool loadHeightMapRAW (io::IReadFile *file, s32 bitsPerPixel=16, bool signedData=false, bool floatVals=false, s32 width=0, video::SColor vertexColor=video::SColor(255, 255, 255, 255), s32 smoothFactor=0)=0
    Initializes the terrain data. Loads the vertices from the heightMapFile.
- virtual bool overrideLODDistance (s32 LOD, f64 newDistance)=0
    Override the default generation of distance thresholds.
- virtual void scaleTexture (f32 scale=1.0f, f32 scale2=0.0f)=0
    Scales the base texture, similar to makePlanarTextureMapping.
- virtual void setCameraMovementDelta (f32 delta)=0
    Sets the movement camera threshold.
- virtual void setCameraRotationDelta (f32 delta)=0
    Sets the rotation camera threshold.
- virtual void setDynamicSelectorUpdate (bool bVal)=0
    Sets whether or not the node should dynamically update its associated selector when the geomipmap data changes.
- virtual void setLODOfPatch (s32 patchX, s32 patchZ, s32 LOD=0)=0
    Manually sets the LOD of a patch.

## Detailed Description

A scene node for displaying terrain using the geo mip map algorithm.

The code for the TerrainSceneNode is based on the Terrain renderer by Soconne and the GeoMipMapSceneNode developed by Spintz. They made their code available for Irrlicht and allowed it to be distributed under this licence. I only modified some parts. A lot of thanks go to them.

This scene node is capable of very quickly loading terrains and updating the indices at runtime to enable viewing very large terrains. It uses a CLOD (Continuous Level of Detail) algorithm which updates the indices for each patch based on a LOD (Level of Detail) which is determined based on a patch's distance from the camera.

The Patch Size of the terrain must always be a size of ( 2^N+1, i.e. 8+1(9), 16+1(17), etc. ). The MaxLOD available is directly dependent on the patch size of the terrain. LOD 0 contains all of the indices to draw all the triangles at the max detail for a patch. As each LOD goes up by 1 the step taken, in generating indices increases by - 2^LOD, so for LOD 1, the step taken is 2, for LOD 2, the step taken is 4, LOD 3 - 8, etc. The step can be no larger than the size of the patch, so having a LOD of 8, with a patch size of 17, is asking the algoritm to generate indices every 2^8 ( 256 ) vertices, which is not possible with a patch size of 17. The maximum LOD for a patch size of 17 is 2^4 ( 16 ). So, with a MaxLOD of 5, you'll have LOD 0 ( full detail ), LOD 1 ( every 2 vertices ), LOD 2 ( every 4 vertices ), LOD 3 ( every 8 vertices ) and LOD 4 ( every 16 vertices ).

Definition at line 49 of file ITerrainSceneNode.h.

## Constructor & Destructor Documentation

irr::scene::ITerrainSceneNode::ITerrainSceneNode | ( | ISceneNode * | parent,
|  | ISceneManager * | mgr,
|  | s32 | id,
|  | const core::vector3df & | position = `core::vector3df(0.0f, 0.0f, 0.0f)`,
|  | const core::vector3df & | rotation = `core::vector3df(0.0f, 0.0f, 0.0f)`,
|  | const core::vector3df & | scale = `core::vector3df(1.0f, 1.0f, 1.0f)`
| ) |  | `[inline]`

Constructor.

Definition at line 53 of file ITerrainSceneNode.h.

## Member Function Documentation

virtual const core::aabbox3d<f32>& irr::scene::ITerrainSceneNode::getBoundingBox | ( |  | ) | const`[pure virtual]`

Get the bounding box of the terrain.

Returns:
  The bounding box of the entire terrain.

Implements irr::scene::ISceneNode.

virtual const core::aabbox3d<f32>& irr::scene::ITerrainSceneNode::getBoundingBox | ( | s32 | patchX,
|  | s32 | patchZ
| ) |  | const`[pure virtual]`

Get the bounding box of a patch.

Returns:
  The bounding box of the chosen patch.

virtual s32 irr::scene::ITerrainSceneNode::getCurrentLODOfPatches | ( | core::array< s32 > & | LODs | ) | const`[pure virtual]`

Populates an array with the CurrentLOD of each patch.

Parameters:

  LODs | A reference to a core::array<s32> to hold the values

Returns:
  Number of elements in the array

virtual f32 irr::scene::ITerrainSceneNode::getHeight | ( | f32 | x,
|  | f32 | y
| ) |  | const`[pure virtual]`

Get height of a point of the terrain.

virtual u32 irr::scene::ITerrainSceneNode::getIndexCount | ( |  | ) | const`[pure virtual]`

Get the number of indices currently in the meshbuffer.

Returns:
  The index count.

virtual s32 irr::scene::ITerrainSceneNode::getIndicesForPatch | ( | core::array< u32 > & | indices,
|  | s32 | patchX,
|  | s32 | patchZ,
|  | s32 | LOD = `0`
| ) |  | `[pure virtual]`

Gets the indices for a specified patch at a specified Level of Detail.

Parameters:

  indices | A reference to an array of u32 indices.
  patchX | Patch x coordinate.
  patchZ | Patch z coordinate.
  LOD | The level of detail to get for that patch. If -1, then get the CurrentLOD. If the CurrentLOD is set to -1, meaning it's not shown, then it will retrieve the triangles at the highest LOD (0).

Returns:
  Number of indices put into the buffer.

virtual IMesh* irr::scene::ITerrainSceneNode::getMesh | ( |  | ) | `[pure virtual]`

Get pointer to the mesh.

Returns:
  Pointer to the mesh.

virtual void irr::scene::ITerrainSceneNode::getMeshBufferForLOD | ( | IDynamicMeshBuffer & | mb,
|  | s32 | LOD = `0`
| ) |  | const`[pure virtual]`

Gets the meshbuffer data based on a specified level of detail.

Parameters:

  mb | A reference to an IDynamicMeshBuffer object
  LOD | The level of detail you want the indices from.

virtual IMeshBuffer* irr::scene::ITerrainSceneNode::getRenderBuffer | ( |  | ) | `[pure virtual]`

Get pointer to the buffer used by the terrain (most users will not need this)

virtual const core::vector3df& irr::scene::ITerrainSceneNode::getTerrainCenter | ( |  | ) | const`[pure virtual]`

Get center of terrain.

virtual bool irr::scene::ITerrainSceneNode::loadHeightMap | ( | io::IReadFile * | file,
|  | video::SColor | vertexColor = `video::SColor(255, 255, 255, 255)`,
|  | s32 | smoothFactor = `0`
| ) |  | `[pure virtual]`

Initializes the terrain data. Loads the vertices from the heightMapFile.

The file must contain a loadable image of the heightmap. The heightmap must be square.

Parameters:

  file | The file to read the image from. File is not rewinded.
  vertexColor | Color of all vertices.
  smoothFactor | Number of smoothing passes.

virtual bool irr::scene::ITerrainSceneNode::loadHeightMapRAW | ( | io::IReadFile * | file,
|  | s32 | bitsPerPixel = `16`,
|  | bool | signedData = `false`,
|  | bool | floatVals = `false`,
|  | s32 | width = `0`,
|  | video::SColor | vertexColor = `video::SColor(255, 255, 255, 255)`,
|  | s32 | smoothFactor = `0`
| ) |  | `[pure virtual]`

Initializes the terrain data. Loads the vertices from the heightMapFile.

The data is interpreted as (signed) integers of the given bit size or floats (with 32bits, signed). Allowed bitsizes for integers are 8, 16, and 32. The heightmap must be square.

Parameters:

  file | The file to read the RAW data from. File is not rewinded.
  bitsPerPixel | Size of data if integers used, for floats always use 32.
  signedData | Whether we use signed or unsigned ints, ignored for floats.
  floatVals | Whether the data is float or int.
  width | Width (and also Height, as it must be square) of the heightmap. Use 0 for autocalculating from the filesize.
  vertexColor | Color of all vertices.
  smoothFactor | Number of smoothing passes.

virtual bool irr::scene::ITerrainSceneNode::overrideLODDistance | ( | s32 | LOD,
|  | f64 | newDistance
| ) |  | `[pure virtual]`

Override the default generation of distance thresholds.

For determining the LOD a patch is rendered at. If any LOD is overridden, then the scene node will no longer apply scaling factors to these values. If you override these distances, and then apply a scale to the scene node, it is your responsibility to update the new distances to work best with your new terrain size.

virtual void irr::scene::ITerrainSceneNode::scaleTexture | ( | f32 | scale = `1.0f`,
|  | f32 | scale2 = `0.0f`
| ) |  | `[pure virtual]`

Scales the base texture, similar to makePlanarTextureMapping.

Parameters:

  scale | The scaling amount. Values above 1.0 increase the number of time the texture is drawn on the terrain. Values below 0 will decrease the number of times the texture is drawn on the terrain. Using negative values will flip the texture, as well as still scaling it.
  scale2 | If set to 0 (default value), this will set the second texture coordinate set to the same values as in the first set. If this is another value than zero, it will scale the second texture coordinate set by this value.

virtual void irr::scene::ITerrainSceneNode::setCameraMovementDelta | ( | f32 | delta | ) | `[pure virtual]`

Sets the movement camera threshold.

It is used to determine when to recalculate indices for the scene node. The default value is 10.0f.

virtual void irr::scene::ITerrainSceneNode::setCameraRotationDelta | ( | f32 | delta | ) | `[pure virtual]`

Sets the rotation camera threshold.

It is used to determine when to recalculate indices for the scene node. The default value is 1.0f.

virtual void irr::scene::ITerrainSceneNode::setDynamicSelectorUpdate | ( | bool | bVal | ) | `[pure virtual]`

Sets whether or not the node should dynamically update its associated selector when the geomipmap data changes.

Parameters:

  bVal,: | Boolean value representing whether or not to update selector dynamically.

virtual void irr::scene::ITerrainSceneNode::setLODOfPatch | ( | s32 | patchX,
|  | s32 | patchZ,
|  | s32 | LOD = `0`
| ) |  | `[pure virtual]`

Manually sets the LOD of a patch.

Parameters:

  patchX | Patch x coordinate.
  patchZ | Patch z coordinate.
  LOD | The level of detail to set the patch to.

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

- ITerrainSceneNode.h