API Reference

Class TCastleTerrain

Description
Hierarchy
Fields
Methods
Properties

Unit

CastleTerrain

Declaration

type TCastleTerrain = class(TCastleTransform)

Description

Terrain.

Assign Data to provide some non-trivial height map, you can use there:

  • TCastleTerrainNoise to generate a height map using a dedicated algorithm for terrain generation, using smooth noise and special tricks to have smooth and heteregeneous terrain.

  • TCastleTerrainImage to generate a height map from intensities of a simple 2D image.

  • TCastleTerrainCombine to combine the above options in any expression (take minimum, maximum, sum, multiply).

The terrain starts as a standard mesh with a TPhysicalMaterialNode material. We apply on it a special affect to mix 4 layers, where each layer has a separate color and texture.

  • Each layer has a color (white by default), texture (none by default, that behaves like white) and UV scale. See TCastleTerrainLayer. Each layer is a property like Layer1, Layer2, Layer3, Layer4.

  • Only the RBG channels of textures matter, alpha is ignored.

  • Layer 1 is used for flat terrain on lower heights.

  • Layer 2 is used for steep terrain on lower heights.

  • Layer 3 is used for flat terrain on higher heights.

  • Layer 4 is used for steep terrain on higher heights.

  • The meaning of "lower" and "higher" heights is determined by Height1 and Height2. Below Height1 we show only layers 1+2, above Height2 we show only layers 3+4, between we show a smooth interpolation between them.

  • The meaning of "flat" and "steep" is determined by looking at terrain normals emphasized by SteepEmphasize.

  • The influence of this effect can be controlled by LayersInfluence.

Hierarchy

Overview

Fields

Public nested const LayersCount = 4;
Public nested const HeightsCount = 2;
Public nested const DefaultSubdivisions = 64;
Public nested const DefaultSize = 100;
Public nested const DefaultHeight1 = 4.0;
Public nested const DefaultHeight2 = 8.0;
Public nested const DefaultHeight: array [1..HeightsCount] of Single = ( DefaultHeight1, DefaultHeight2 );
Public nested const DefaultLayersInfluence = 1.0;
Public nested const DefaultSteepEmphasize = 2.0;

Methods

Protected procedure Loaded; override;
Public constructor Create(AOwner: TComponent); override;
Public destructor Destroy; override;
Public function PropertySections(const PropertyName: String): TPropertySections; override;
Public function HasColliderMesh: Boolean; override;
Public procedure ColliderMesh(const TriangleEvent: TTriangleEvent); override;

Properties

Public property Subdivisions: TVector2 read FSubdivisions write SetSubdivisions;
Public property Size: TVector2 read FSize write SetSize;
Public property QueryOffset: TVector2 read FQueryOffset write SetQueryOffset;
Published property RenderOptions: TCastleRenderOptions read GetRenderOptions;
Published property Layer1: TCastleTerrainLayer index 1 read GetLayer;
Published property Layer2: TCastleTerrainLayer index 2 read GetLayer;
Published property Layer3: TCastleTerrainLayer index 3 read GetLayer;
Published property Layer4: TCastleTerrainLayer index 4 read GetLayer;
Published property Data: TCastleTerrainData read FData write SetData;
Published property Triangulate: Boolean read FTriangulate write SetTriangulate default true;
Published property SteepEmphasize: Single read FSteepEmphasize write SetSteepEmphasize default DefaultSteepEmphasize;
Published property Height1: Single index 1 read GetHeight write SetHeight default DefaultHeight1;
Published property Height2: Single index 2 read GetHeight write SetHeight default DefaultHeight2;
Published property LayersInfluence: Single read FLayersInfluence write SetLayersInfluence default DefaultLayersInfluence;
Published property PreciseCollisions: Boolean read FPreciseCollisions write SetPreciseCollisions default true;
Published property SizePersistent: TCastleVector2Persistent read FSizePersistent ;
Published property QueryOffsetPersistent: TCastleVector2Persistent read FQueryOffsetPersistent ;
Published property SubdivisionsPersistent: TCastleVector2Persistent read FSubdivisionsPersistent ;

Description

Fields

Public nested const LayersCount = 4;

Texture layers to render this terrain.

Public nested const HeightsCount = 2;

This item has no description.

Public nested const DefaultSubdivisions = 64;

This item has no description.

Public nested const DefaultSize = 100;

This item has no description.

Public nested const DefaultHeight1 = 4.0;

This item has no description.

Public nested const DefaultHeight2 = 8.0;

This item has no description.

Public nested const DefaultHeight: array [1..HeightsCount] of Single = ( DefaultHeight1, DefaultHeight2 );

Default values for Height1, Height2 etc.

Note: This array duplicates information in constants DefaultHeight1, DefaultHeight2 etc. Unfortunately we need the simple constants too, to specify properties default values like "default DefaultHeight0". Using "default DefaultHeight[0]" doesn't work in FPC (nor in Delphi, but that's because Delphi cannot handle Single defaults at all).

Public nested const DefaultLayersInfluence = 1.0;

This item has no description.

Public nested const DefaultSteepEmphasize = 2.0;

This item has no description.

Methods

Protected procedure Loaded; override;

This item has no description.

Public constructor Create(AOwner: TComponent); override;

This item has no description.

Public destructor Destroy; override;

This item has no description.

Public function PropertySections(const PropertyName: String): TPropertySections; override;

This item has no description. Showing description inherited from TCastleComponent.PropertySections.

Section where to show property in the editor.

Public function HasColliderMesh: Boolean; override;

This item has no description. Showing description inherited from TCastleTransform.HasColliderMesh.

Does this transform have a collision mesh that TCastleMeshCollider can use. Default implementation returns False.

Public procedure ColliderMesh(const TriangleEvent: TTriangleEvent); override;

This item has no description. Showing description inherited from TCastleTransform.ColliderMesh.

Enumerate triangles for a collision mesh that TCastleMeshCollider can use.

Properties

Public property Subdivisions: TVector2 read FSubdivisions write SetSubdivisions;

How dense is the mesh. By default this is (DefaultSubdivisions,DefaultSubdivisions).

Changing this requires rebuild of terrain geometry, so it's costly. Avoid doing it at runtime.

Public property Size: TVector2 read FSize write SetSize;

Size of the generated shape and also the underlying range to query the TCastleTerrainNoise data for heights.

Note that changing this does not just scale the same geometry, if TCastleTerrainNoise is used for Data. The TCastleTerrainNoise uses the size you set here to determine what heights to query from a smooth noise. This has a nice effect that increasing the size adds additional pieces of terrain adjacent to the previous terrain, and the previous terrain shape is still visible at the same place.

Be sure to increase also Subdivisions when increasing this field, to keep seeing the same detail.

By default this is (DefaultSize,DefaultSize).

Changing this requires rebuild of terrain geometry, so it's costly. Avoid doing it at runtime.

Public property QueryOffset: TVector2 read FQueryOffset write SetQueryOffset;

Offset the range of input values used to query the Data.

By default (when this is zero) we query the TCastleTerrainData.Height using Coord values ranging in X from -Size/2 to Size/2, similarly in Z.

This vector offsets the range of queried values.

It can be used to display a terrain noise matching neighboring terrain noise.

Published property RenderOptions: TCastleRenderOptions read GetRenderOptions;

Options used to render the terrain. Can be used e.g. to toggle wireframe rendering.

Published property Layer1: TCastleTerrainLayer index 1 read GetLayer;

1st layer is displayed on lower heights and more flat terrain. See TCastleTerrain for a full description how do we mix layers.

Published property Layer2: TCastleTerrainLayer index 2 read GetLayer;

2nd layer is displayed on lower heights and more steep terrain. See TCastleTerrain for a full description how do we mix layers.

Published property Layer3: TCastleTerrainLayer index 3 read GetLayer;

3rd layer is displayed on higher heights and more flat terrain. See TCastleTerrain for a full description how do we mix layers.

Published property Layer4: TCastleTerrainLayer index 4 read GetLayer;

4th layer is displayed on higher heights and more steep terrain. See TCastleTerrain for a full description how do we mix layers.

Published property Data: TCastleTerrainData read FData write SetData;

Data for terrain heights. Changing this requires rebuild of terrain geometry, so it's costly. Avoid doing it at runtime.

Published property Triangulate: Boolean read FTriangulate write SetTriangulate default true;

Do we generate as a set of triangles, or ElevationGrid. TODO: this is internal decision, should behave always like true?

Changing this requires rebuild of terrain geometry, so it's costly. Avoid doing it at runtime.

Published property SteepEmphasize: Single read FSteepEmphasize write SetSteepEmphasize default DefaultSteepEmphasize;

How much should we emphasize the "steep" layers (2nd and 4th layers) at the expense of "flat" layers (1st and 3rd).

SteepEmphasize = 0.0 means that only "flat" layers (1 and 3) are visible. SteepEmphasize = 1.0 means that flat vs steep is a linear interpolation based on normal Y coordinate (but, since most terrains are more flat than steep, in practice the "flat" layers are still more visible). As SteepEmphasize goes toward infinity, the "steep" layers (2 and 4) dominate.

Published property Height1: Single index 1 read GetHeight write SetHeight default DefaultHeight1;

Below Height1 we only display layers 1+2. See TCastleTerrain for a description when do we show show layers and how this property affects it.

Published property Height2: Single index 2 read GetHeight write SetHeight default DefaultHeight2;

Above Height2 we only display layers 3+4. See TCastleTerrain for a description when do we show show layers and how this property affects it.

Published property LayersInfluence: Single read FLayersInfluence write SetLayersInfluence default DefaultLayersInfluence;

How much do the layers affect the final color. 0.0 means that layes are ignored, and the terrain look is a regular mesh look with TPhysicalMaterialNode. 1.0 means maximum influence, the layers determine the base color (TODO: and normals in the future).

Published property PreciseCollisions: Boolean read FPreciseCollisions write SetPreciseCollisions default true;

Resolve collisions precisely with the terrain geometry. When this is False we will only consider the terrain bounding box for collisions, which prevents moving on terrain nicely, picking terrain points with mouse etc. This sets TCastleSceneCore.Spatial.

Published property SizePersistent: TCastleVector2Persistent read FSizePersistent ;

Size that can be visually edited in Castle Game Engine Editor, Lazarus and Delphi. Normal user code does not need to deal with this, instead read or write Size directly.

See also
Size
Size of the generated shape and also the underlying range to query the TCastleTerrainNoise data for heights.
Published property QueryOffsetPersistent: TCastleVector2Persistent read FQueryOffsetPersistent ;

QueryOffset that can be visually edited in Castle Game Engine Editor, Lazarus and Delphi. Normal user code does not need to deal with this, instead read or write QueryOffset directly.

See also
QueryOffset
Offset the range of input values used to query the Data.
Published property SubdivisionsPersistent: TCastleVector2Persistent read FSubdivisionsPersistent ;

Subdivisions that can be visually edited in Castle Game Engine Editor, Lazarus and Delphi. Normal user code does not need to deal with this, instead read or write Subdivisions directly.

See also
Subdivisions
How dense is the mesh.
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