Class TDDSImage

DescriptionHierarchyFieldsMethodsProperties

Unit

Declaration

type TDDSImage = class(TObject)

Description

DDS image file.

Basically, DDS is just a sequence of images (in the Images property). The interpretation of the image sequence depends on other fields: first of all DDSType and Mipmaps.

The basic usage of this class is to load a DDS file: see LoadFromFile, LoadFromStream.

Note that you can write (change) many properties of this class. This allows you to create, or load and edit, DDS files. You can even later save the DDS image back to the stream (like a file) by SaveToStream or SaveToFile. Be careful though: you're responsible then to set all properties to sensible values. For example, the length (and interpretation) of Images list is determined by other properties of this class, so be sure to set them all to something sensible.

Hierarchy

  • TObject
  • TDDSImage

Overview

Methods

Public constructor Create;
Public destructor Destroy; override;
Public function CubeMapImage(const Side: TDDSCubeMapSide; const Level: Cardinal = 0): TEncodedImage;
Public procedure LoadFromStream(Stream: TStream);
Public procedure LoadFromFile(const URL: string);
Public procedure SaveToStream(Stream: TStream);
Public procedure SaveToFile(const URL: string);
Public procedure Close;
Public procedure Flatten3d;
Public procedure DecompressS3TC;
Public class function MatchesURL(const URL: string): boolean;

Properties

Public property Images: TEncodedImageList read FImages;
Public property Width: Cardinal read FWidth write FWidth;
Public property Height: Cardinal read FHeight write FHeight;
Public property DDSType: TDDSType read FDDSType write FDDSType;
Public property Mipmaps: boolean read FMipmaps write FMipmaps;
Public property MipmapsCount: Cardinal read FMipmapsCount write FMipmapsCount;
Public property CubeMapSides: TDDSCubeMapSides read FCubeMapSides write FCubeMapSides;
Public property Depth: Cardinal read FDepth write FDepth;
Public property OwnsFirstImage: boolean read FOwnsFirstImage write FOwnsFirstImage default true;

Description

Methods

Public constructor Create;
 
Public destructor Destroy; override;
 
Public function CubeMapImage(const Side: TDDSCubeMapSide; const Level: Cardinal = 0): TEncodedImage;

Return given side of cube map. Assumes DDSType = dtCubeMap and CubeMapSides = all.

Level is mipmap level. Pass 0 for base level. When not Mipmaps, Level must be 0.

Public procedure LoadFromStream(Stream: TStream);

Load DDS image from any TStream.

Exceptions raised
EInvalidDDS
In case of any error in the file data.
Public procedure LoadFromFile(const URL: string);
 
Public procedure SaveToStream(Stream: TStream);
 
Public procedure SaveToFile(const URL: string);
 
Public procedure Close;

Close all loaded image data. Effectively, this releases all data loaded by LoadFromStream, reverting the object to the state right after creation.

Public procedure Flatten3d;

Convert 3D images in Images list into a sequences of 2D images. Useful utility for 3d (volume) textures.

Normal loading of 3d DDS textures creates single TCastleImage (using Depth possibly > 1) for each mipmap level. Such TCastleImage with depth is comfortable if you want to load this 3d texture into OpenGL (as then the image data is just a continous memory area, loadable by glTexImage3d). But it's not comfortable if you want to display it using some 2D GUI. For example, it's not comfortable for image viewer like glViewImage.

So this method will convert such TCastleImage instances (with Depth > 1) into a sequence of TCastleImage instances all with Depth = 1. This isn't difficult, memory contents on 3d TCastleImage may be splitted into many 2d TCastleImage instances without problems.

Note that it's safe to do this before saving the image. SaveToFile/SaveToStream methods accept both layouts of images (because, as said, memory contents actually are the same before and after splitting).

Note that this may free all Images (possibly even whole Images object), disregarding OwnsFirstImage (as it would be difficult, since it may or may not replace it with new images).

Public procedure DecompressS3TC;

Decompress S3TC images (if any) on the Images list, replacing them with uncompressed equivalents.

Just like Flatten3d: Note that this may free all Images (possibly even whole Images object), disregarding OwnsFirstImage (as it would be difficult, since it may or may not replace it with new images).

Exceptions raised
ECannotDecompressS3TC
If some S3TC image cannot be decompressed for whatever reason.
Public class function MatchesURL(const URL: string): boolean;

Does this URL look like it contains DDS contents. Guesses looking at filename extension.

Properties

Public property Images: TEncodedImageList read FImages;

Images sequence stored in this DDS file.

This has always length > 0 when DDS is successfully loaded (that is, when LoadFromStream method finished without raising any exception).

Public property Width: Cardinal read FWidth write FWidth;
 
Public property Height: Cardinal read FHeight write FHeight;
 
Public property DDSType: TDDSType read FDDSType write FDDSType;
 
Public property Mipmaps: boolean read FMipmaps write FMipmaps;

Does this DDS file contain mipmaps. If True, then all Images are guaranteed to have sizes being power of 2.

Public property MipmapsCount: Cardinal read FMipmapsCount write FMipmapsCount;

Mipmaps count. Always 1 when Mipmaps = False, this is usually comfortable.

Public property CubeMapSides: TDDSCubeMapSides read FCubeMapSides write FCubeMapSides;

Present cube map sides. Valid only when image is loaded and is dtCubeMap.

Public property Depth: Cardinal read FDepth write FDepth;

Depth of volume (3D) texture. Always 1 when DDSType is not dtVolume, this is usually comfortable.

Public property OwnsFirstImage: boolean read FOwnsFirstImage write FOwnsFirstImage default true;

When False, then closing this DDS image will not free Images[0]. Closing happens when you call the Close method or destructor of this object. When this is False, you're responsible to storing and freeing Images[0] later yourself, or you'll get memory leaks.


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