260 lines
7.1 KiB
C
260 lines
7.1 KiB
C
/* -*- tab-width: 4; -*- */
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/* vi: set sw=2 ts=4 expandtab: */
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/* $Id: ee6f7be4d43390de78e1815ed158012c78ddeff1 $ */
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/*
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* Copyright 2010-2020 The Khronos Group Inc.
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @internal
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* @file checkheader.c
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* @~English
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*
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* @brief Function to verify a KTX file header
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*
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* @author Mark Callow, HI Corporation
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*/
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/*
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* Author: Georg Kolling, Imagination Technology with modifications
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* by Mark Callow, HI Corporation.
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*/
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#include <assert.h>
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#include <string.h>
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#include "ktx.h"
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#include "ktxint.h"
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/**
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* @internal
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* @~English
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* @brief Check a KTX file header.
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*
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* As well as checking that the header identifies a KTX file, the function
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* sanity checks the values and returns information about the texture in a
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* struct KTX_supplementary_info.
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*
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* @param pHeader pointer to the KTX header to check
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* @param pSuppInfo pointer to a KTX_supplementary_info structure in which to
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* return information about the texture.
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*
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* @author Georg Kolling, Imagination Technology
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* @author Mark Callow, HI Corporation
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*/
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KTX_error_code ktxCheckHeader1_(KTX_header* pHeader,
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KTX_supplemental_info* pSuppInfo)
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{
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ktx_uint8_t identifier_reference[12] = KTX_IDENTIFIER_REF;
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ktx_uint32_t max_dim;
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assert(pHeader != NULL && pSuppInfo != NULL);
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/* Compare identifier, is this a KTX file? */
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if (memcmp(pHeader->identifier, identifier_reference, 12) != 0)
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{
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return KTX_UNKNOWN_FILE_FORMAT;
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}
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if (pHeader->endianness == KTX_ENDIAN_REF_REV)
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{
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/* Convert endianness of pHeader fields. */
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_ktxSwapEndian32(&pHeader->glType, 12);
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if (pHeader->glTypeSize != 1 &&
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pHeader->glTypeSize != 2 &&
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pHeader->glTypeSize != 4)
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{
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/* Only 8-, 16-, and 32-bit types supported so far. */
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return KTX_FILE_DATA_ERROR;
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}
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}
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else if (pHeader->endianness != KTX_ENDIAN_REF)
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{
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return KTX_FILE_DATA_ERROR;
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}
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/* Check glType and glFormat */
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pSuppInfo->compressed = 0;
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if (pHeader->glType == 0 || pHeader->glFormat == 0)
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{
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if (pHeader->glType + pHeader->glFormat != 0)
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{
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/* either both or none of glType, glFormat must be zero */
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return KTX_FILE_DATA_ERROR;
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}
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pSuppInfo->compressed = 1;
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}
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if (pHeader->glFormat == pHeader->glInternalformat) {
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// glInternalFormat is either unsized (which is no longer and should
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// never have been supported by libktx) or glFormat is sized.
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return KTX_FILE_DATA_ERROR;
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}
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/* Check texture dimensions. KTX files can store 8 types of textures:
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1D, 2D, 3D, cube, and array variants of these. There is currently
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no GL extension for 3D array textures. */
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if ((pHeader->pixelWidth == 0) ||
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(pHeader->pixelDepth > 0 && pHeader->pixelHeight == 0))
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{
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/* texture must have width */
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/* texture must have height if it has depth */
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return KTX_FILE_DATA_ERROR;
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}
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if (pHeader->pixelDepth > 0)
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{
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if (pHeader->numberOfArrayElements > 0)
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{
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/* No 3D array textures yet. */
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return KTX_UNSUPPORTED_TEXTURE_TYPE;
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}
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pSuppInfo->textureDimension = 3;
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}
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else if (pHeader->pixelHeight > 0)
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{
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pSuppInfo->textureDimension = 2;
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}
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else
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{
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pSuppInfo->textureDimension = 1;
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}
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if (pHeader->numberOfFaces == 6)
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{
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if (pSuppInfo->textureDimension != 2)
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{
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/* cube map needs 2D faces */
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return KTX_FILE_DATA_ERROR;
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}
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}
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else if (pHeader->numberOfFaces != 1)
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{
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/* numberOfFaces must be either 1 or 6 */
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return KTX_FILE_DATA_ERROR;
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}
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/* Check number of mipmap levels */
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if (pHeader->numberOfMipLevels == 0)
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{
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pSuppInfo->generateMipmaps = 1;
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pHeader->numberOfMipLevels = 1;
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}
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else
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{
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pSuppInfo->generateMipmaps = 0;
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}
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/* This test works for arrays too because height or depth will be 0. */
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max_dim = MAX(MAX(pHeader->pixelWidth, pHeader->pixelHeight), pHeader->pixelDepth);
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if (max_dim < ((ktx_uint32_t)1 << (pHeader->numberOfMipLevels - 1)))
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{
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/* Can't have more mip levels than 1 + log2(max(width, height, depth)) */
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return KTX_FILE_DATA_ERROR;
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}
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return KTX_SUCCESS;
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}
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/**
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* @internal
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* @~English
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* @brief Check a KTX2 file header.
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*
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* As well as checking that the header identifies a KTX 2 file, the function
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* sanity checks the values and returns information about the texture in a
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* struct KTX_supplementary_info.
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*
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* @param pHeader pointer to the KTX header to check
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* @param pSuppInfo pointer to a KTX_supplementary_info structure in which to
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* return information about the texture.
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*
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* @author Mark Callow, HI Corporation
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*/
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KTX_error_code ktxCheckHeader2_(KTX_header2* pHeader,
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KTX_supplemental_info* pSuppInfo)
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{
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// supp info is compressed, generateMipmaps and num dimensions. Don't need
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// compressed as formatSize gives us that. I think the other 2 aren't needed.
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ktx_uint8_t identifier_reference[12] = KTX2_IDENTIFIER_REF;
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assert(pHeader != NULL && pSuppInfo != NULL);
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ktx_uint32_t max_dim;
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/* Compare identifier, is this a KTX file? */
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if (memcmp(pHeader->identifier, identifier_reference, 12) != 0)
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{
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return KTX_UNKNOWN_FILE_FORMAT;
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}
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/* Check texture dimensions. KTX files can store 8 types of textures:
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1D, 2D, 3D, cube, and array variants of these. There is currently
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no extension for 3D array textures in any 3D API. */
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if ((pHeader->pixelWidth == 0) ||
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(pHeader->pixelDepth > 0 && pHeader->pixelHeight == 0))
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{
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/* texture must have width */
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/* texture must have height if it has depth */
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return KTX_FILE_DATA_ERROR;
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}
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if (pHeader->pixelDepth > 0)
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{
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if (pHeader->layerCount > 0)
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{
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/* No 3D array textures yet. */
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return KTX_UNSUPPORTED_TEXTURE_TYPE;
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}
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pSuppInfo->textureDimension = 3;
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}
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else if (pHeader->pixelHeight > 0)
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{
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pSuppInfo->textureDimension = 2;
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}
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else
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{
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pSuppInfo->textureDimension = 1;
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}
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if (pHeader->faceCount == 6)
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{
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if (pSuppInfo->textureDimension != 2)
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{
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/* cube map needs 2D faces */
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return KTX_FILE_DATA_ERROR;
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}
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}
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else if (pHeader->faceCount != 1)
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{
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/* numberOfFaces must be either 1 or 6 */
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return KTX_FILE_DATA_ERROR;
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}
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// Check number of mipmap levels
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if (pHeader->levelCount == 0)
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{
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pSuppInfo->generateMipmaps = 1;
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pHeader->levelCount = 1;
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}
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else
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{
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pSuppInfo->generateMipmaps = 0;
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}
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// This test works for arrays too because height or depth will be 0.
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max_dim = MAX(MAX(pHeader->pixelWidth, pHeader->pixelHeight), pHeader->pixelDepth);
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if (max_dim < ((ktx_uint32_t)1 << (pHeader->levelCount - 1)))
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{
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// Can't have more mip levels than 1 + log2(max(width, height, depth))
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return KTX_FILE_DATA_ERROR;
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}
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return KTX_SUCCESS;
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}
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