This component provides extensive textures support.
2D textures may be loaded from image files (
movie files (
MovieTexture) or encoded directly in VRML/X3D files
ImageTexture with data urls).
Multiple textures may be overlayed on a single polygon in a variety
of ways. Texture coordinates may be explicitly provided or automatically
calculated, and may be transformed.
For demos and tests of these features,
multi_texturing subdirectories inside our VRML/X3D demo models.
These nodes define a texture,
from an external file (in the usual case of
or embedded inside the X3D file (in case of
ImageTexture using data URI).
ImageTexture allows various texture formats,
including JPEG, PNG, GIF, BMP, PPM, RGBE, KTX, DDS.
See glViewImage documentation for a detailed list.
Note about alpha channel: alpha channel of the textures is fully supported, both a simple yes-no transparency (done by alpha_test in OpenGL) and full range transparency (done by blending in OpenGL, just like partially transparent materials). See "override alpha channel detection" extension description for details. The bottom line is: everything will magically work fast and look perfect.
These nodes specify how the texture is mapped onto the shape. All X3D nodes have some "default" texture mapping, if you don't provide explicit texture coordinates.
This node defines a texture that is actually a (playing) movie file.
TODO: for now, the sound of the movie is not played.
Current implementation keeps the whole encoded video in memory (images may be discarded after loading (by TCastleSceneCore.FreeResources feature), but still the textures for all frames are kept in memory). The disadvantage is that this makes it impractical to load "real" movies, normal 2-hour movie will most usually eat all of your memory. The advantage is that once the movie is loaded, the playback is super-fast, just like you would display normal nodes with static textures. Since there's no streaming, decoding etc. in the background while you browse your models.
In other words, this is quite perfect for movie textures with game effects, like smoke or flame. But it's not a substitute for your "real" multimedia movie player.
ffmpeg must be installed and available on $PATH to actually open any movie format. See instructions for installing ffmpeg in view3dscene docs. Thanks to ffmpeg, we can handle probably any movie format you will ever need to open.
We can also open movies from images sequence. This doesn't require ffmpeg, and allows for some tricks (movie texture with alpha channel). See "Movies from images sequence" extension description.
Multi-texturing means that you can use multiple textures on a single polygon (face). A number of textures can be mixed, in a way resembling the "layers" concept you from image editing applications (like GIMP or Photoshop). For each layer, you specify which texture to use, the "mode" (how it is mixed), also each layer may have it's own texture coordinates.
We support for all the fields from X3D specification (unless mentioned below).
We implement most modes (in
MultiTexture.mode), except (TODO):
"SPECULAR" are treated the same.
Note that the multi-texturing specification of X3D has unfortunately some issues. Clarifications and our extensions are documented here.
Note that in case of 2D games, when the camera cannot move freely, you can often use multiple polygons (each with a single texture) rendered on top of each other (positioned with slight shift), instead of using a single polygon with multi-texturing. Both choices are fine, in principle: use whichever is more comfortable for your case.
Supported modes are now "SPHERE", "COORD", "COORD-EYE", "CAMERASPACEPOSITION", "CAMERASPACENORMAL", "CAMERASPACEREFLECTIONVECTOR". We also allow some extensions: "WORLDSPACEREFLECTIONVECTOR" and "WORLDSPACENORMAL", "BOUNDS", "BOUNDS2D" and "BOUNDS3D".
Note that "CAMERASPACEPOSITION" and "COORD-EYE" are exactly the same thing. Google confirms it (e.g. this source code also treats them as equal and in this old bitmanagement spec they mention they are equal).
TODO: not implemented modes: "SPHERE-LOCAL", "NOISE", "NOISE-EYE", "SPHERE-REFLECT", "SPHERE-REFLECT-LOCAL".
Adjust various texture calculation properties.
anisotropicDegree fields are supported.
TODO: the rest
TextureProperties fields are not supported yet.
In particular, if you're looking for a way to use GPU compressed textures,
simply place the GPU compressed texture data in DDS files
(it's a better idea than using the
Note a common mistake when using the
texture filtering gets ugly. This is a common mistake,
because the X3D specification makes the behavior unexpected:
TextureProperties node by default has
minificationFilter fields set to
which instructs us (and every other valid X3D browser) to use
the most ugly filtering (without mipmaps, without even linear filtering).
To avoid it, always override these fields to
For example, instead of using this:
<TextureProperties anisotropicDegree="4" magnificationFilter="DEFAULT" minificationFilter="DEFAULT" />
"DEFAULT" above means to use the browser-specific texture
filtering modes, for us this means to use values in
Scene.Attributes.MagnificationFilter which by default are nice
See glViewImage features for the full list of 2D image formats we can handle.
Surface (DDS) image format is supported. This format allows to store textures
compressed for GPU (S3TC), storing mipmaps, cube maps, and volume (3D) textures.
A number of technical details about DDS implementation are below, but in short:
we try to support all formats and all options of DDS in a standard way.
You may find example DDS images inside our VRML/X3D demo models (look inside
textures subdirectory for
*.dds files). You can open them directly with our image viewer glViewImage.
Cube maps in DDS are supposed to be oriented as usual for DDS:
Which means that they match Direct X "positive/negative x/y/z". For OpenGL rendering we swap positive/negative Y faces (because Direct X has left-handed coordinate system, see here for drawing of DirectX cube map images orientation and compare with OpenGL cube map orientation).
It's also a different orientation then the one of X3D ComposedCubeMap specification (left/right, bottom/top, front/back, with bottom/top on Y axis; X3D orientation needs rotating left,right,front,back images by 180 degrees for OpenGL orientation).
Images in DDS are supposed to be written from top to bottom row, as is the standard in DDS. (One particular tool, AMD CubeMapGen, allows to invert rows of the DDS images to match OpenGL bottom-to-top ordering; don't use this — we expect rows ordered as is standard in DDS, top-to-bottom.) Internally, our engine just inverts the rows for OpenGL (yes, this is doable also for S3TC compressed images.)
Pixel formats supported:
Absolutely all uncompressed non-float pixel formats are supported.
The formats that are currently loaded optimally are ABGR8, BGR8, AL8, L8. They translate to RGBA8, RGB8 etc. OpenGL formats (reversed order, as DDS color masks are little-endian). Popular ARGB8 and RGB8 are also loaded very fast.
Grayscale (luminance) images are allowed. AL8 and L8 are optimized. Note that grayscale images aren't officially allowed by DDS docs, but at least GIMP-DDS plugin can write it (just sets all R, G and B masks equal, and doesn't set any of DDPF_RGB, DDPF_FOURCC, DDPF_PALETTEINDEXED8).
Also only-alpha images are allowed (another undocumented DDS feature, GIMP-DDS can write it, for now they will result in grayscale(white) with alpha image).
Compressed texture formats handled: DXT1, DXT3, DXT5 are supported. Texture with DXT1 is always treated like a texture with simple (yes/no) alpha channel (so it will be rendered with alpha testing) and DXT3 / DXT5 are always treated like a texture with full range alpha channel (so they will be rendered with blending).
Texture compression formats commonly used on mobile platforms are supported as well: ATITC, PVRTC, ETC1.
Both normal (2D) textures and cube maps may be compressed. (There is no compression possible for 3D textures — neither DDS format allows it, nor do common graphic cards.)
Reading float textures from DDS is for now not supported. Our engine supports float textures (see TRGBFloatImage class), but DDS reader doesn't support them yet. Please submit a feature request (through forum or ticket system), preferably with some test images, if you need them.
If DDS file includes mipmaps, and mipmaps are required for texture minification filter, we will use DDS mipmaps (instead of generating mipmaps automatically). Works for all 2D, 3D, cubemap DDS files.
Since Castle Game Engine 6.3 we support Khronos KTX texture format. KTX is in many ways an alternative to DDS, with a clean specification, supporting the same features (GPU compression, 2D and 3D textures...). The KTX Khronos page has links to various tools that can create KTX files, and to the KTX specification.
The features of KTX that we support:
1D, 2D and 3D images (textures).
Various uncompressed texture formats. RGB + alpha, RGB, luminance, luminance + alpha, luminance 16-bit, luminance float32 texture... RGB can be swapped as BGR (it doesn't matter for performance in practice, either way).
More uncompressed formats can be trivially added, just submit a bugreport with a sample KTX file.
Texture arrays. Programmers: iterate over TCompositeImage.Images to access all the items of the array.
Configurable orientation. KTX data may be specified in top-to-bottom or bottom-to-top order. For 3D images, the slices can additionally be in front-to-back or back-to-front order. This is specified by a special
KTXorientation field inside the KTX file (see the KTX specification for details) and we support it fully.
GPU-compressed data, like
We don't support (yet):
Both of these features are quite trivial to implement now, so please ask if you need them :)
Copyright Michalis Kamburelis. Thanks go to Paweł Wojciechowicz from Cat-astrophe Games for various graphics. Even this documentation is open-source, you can redistribute it on terms of the GNU General Public License.