Defined in File Ifc2x3.h
IfcPixelTexture: public Ifc2x3::IfcSurfaceTexture¶
An IfcPixelTexture provides a 2D image-based texture map as an explicit array of pixel values (list of Pixel binary attributes). In contrary to the IfcImageTexture the IfcPixelTexture holds a 2 dimensional list of pixel color (and opacity) directly, instead of referencing to an URL.
The following definitions from ISO/IEC 19775-1 X3D Architecture and base components (X3D Specification) apply:
The PixelTexture node defines a 2D image-based texture map as an explicit array of pixel values (image field) and parameters controlling tiling repetition of the texture onto geometry. Texture maps are defined in a 2D coordinate system (s, t) that ranges from 0.0 to 1.0 in both directions. The bottom edge of the pixel image corresponds to the S-axis of the texture map, and left edge of the pixel image corresponds to the T-axis of the texture map. The lower-left pixel of the pixel image corresponds to s=0.0, t=0.0, and the top-right pixel of the image corresponds to s = 1.0, t = 1.0. The Image field specifies a single uncompressed 2-dimensional pixel image. Image fields contain three integers representing the width, height and number of components in the image, followed by width×height hexadecimal values representing the pixels in the image. Pixel values are limited to 256 levels of intensity (that is, 0x00-0xFF hexadecimal).
A one-component image specifies one-byte hexadecimal value representing the intensity of the image. For example, 0xFF is full intensity in hexadecimal (255 in decimal), 0x00 is no intensity (0 in decimal). A two-component image specifies the intensity in the first (high) byte and the alpha opacity in the second (low) byte. Pixels in a three-component image specify the red component in the first (high) byte, followed by the green and blue components (for example, 0xFF0000 is red, 0x00FF00 is green, 0x0000FF is blue). Four-component images specify the alpha opacity byte after red/green/blue (e.g., 0x0000FF80 is semi-transparent blue). A value of 00 is completely transparent, FF is completely opaque, 80 is semi-transparent.
Note that alpha equals (1.0 -transparency), if alpha and transparency each range from 0.0 to 1.0.
HISTORY: New class in IFC2x2.
The number of pixels in width (S) direction.
The number of pixels in height (T) direction.
Indication whether the pixel values contain a 1, 2, 3, or 4 colour component.
Flat list of hexadecimal values, each describing one pixel by 1, 2, 3, or 4 components.
IFC2x Edition 3 CHANGE The data type has been changed from STRING to BINARY.