.TH "ktxAstcParams" 3 "Sun Jun 14 2026 18:00:57" "Version 0.0.0" "libktx Reference" \" -*- nroff -*-
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.SH NAME
ktxAstcParams \- Structure for passing extended parameters to ktxTexture_CompressAstc\&.  

.SH SYNOPSIS
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.PP
.PP
\fR#include <ktx\&.h>\fP
.SS "Data Fields"

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.ti -1c
.RI "ktx_uint32_t \fBstructSize\fP"
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.RI "ktx_bool_t \fBverbose\fP"
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.RI "ktx_uint32_t \fBthreadCount\fP"
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.RI "ktx_uint32_t \fBblockDimension\fP"
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.RI "ktx_uint32_t \fBmode\fP"
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.RI "ktx_uint32_t \fBqualityLevel\fP"
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.RI "ktx_bool_t \fBnormalMap\fP"
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.RI "ktx_bool_t \fBperceptual\fP"
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.RI "char \fBinputSwizzle\fP [4]"
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.in -1c
.SH "Detailed Description"
.PP 
Structure for passing extended parameters to ktxTexture_CompressAstc\&. 

Passing a struct initialized to 0 (e\&.g\&. " = {0};") will use blockDimension 4x4, mode LDR and qualityLevel FASTEST\&. Setting qualityLevel to KTX_PACK_ASTC_QUALITY_LEVEL_MEDIUM is recommended\&. 
.SH "Field Documentation"
.PP 
.SS "ktx_uint32_t blockDimension"
Combinations of block dimensions that astcenc supports i\&.e\&. 6x6, 8x8, 6x5 etc 
.SS "char inputSwizzle[4]"
A swizzle to provide as input to astcenc\&. It must match the regular expression /^[rgba01]{4}$/\&. 
.SS "ktx_uint32_t mode"
Can be {ldr/hdr} from astcenc 
.SS "ktx_bool_t normalMap"
Tunes codec parameters for better quality on normal maps In this mode normals are compressed to X,Y components Discarding Z component, reader will need to generate Z component in shaders\&. 
.SS "ktx_bool_t perceptual"
The codec should optimize for perceptual error, instead of direct RMS error\&. This aims to improves perceived image quality, but typically lowers the measured PSNR score\&. Perceptual methods are currently only available for normal maps and RGB color data\&. 
.SS "ktx_uint32_t qualityLevel"
astcenc supports -fastest, -fast, -medium, -thorough, -exhaustive 
.SS "ktx_uint32_t structSize"
Size of this struct\&. Used so library can tell which version of struct is being passed\&. 
.SS "ktx_uint32_t threadCount"
Number of threads used for compression\&. Default is 1\&. 
.SS "ktx_bool_t verbose"
If true, prints Astc encoder operation details to \fRstdout\fP\&. Not recommended for GUI apps\&. 

.SH "Author"
.PP 
Generated automatically by Doxygen for libktx Reference from the source code\&.