1a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Copyright 2009 Google Inc. 2a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 3a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Licensed under the Apache License, Version 2.0 (the "License"); 4a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// you may not use this file except in compliance with the License. 5a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// You may obtain a copy of the License at 6a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 7a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// http://www.apache.org/licenses/LICENSE-2.0 8a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 9a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Unless required by applicable law or agreed to in writing, software 10a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// distributed under the License is distributed on an "AS IS" BASIS, 11a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// See the License for the specific language governing permissions and 13a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// limitations under the License. 14a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 15a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#ifndef __etc1_h__ 16a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#define __etc1_h__ 17a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 18a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#define ETC1_ENCODED_BLOCK_SIZE 8 19a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#define ETC1_DECODED_BLOCK_SIZE 48 20a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 21a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#ifndef ETC1_RGB8_OES 22a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#define ETC1_RGB8_OES 0x8D64 23a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#endif 24a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 25a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichtypedef unsigned char etc1_byte; 26a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichtypedef int etc1_bool; 27a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichtypedef unsigned int etc1_uint32; 28a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 29a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#ifdef __cplusplus 30a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichextern "C" { 31a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#endif 32a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 33a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Encode a block of pixels. 34a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 35a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pIn is a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a 36a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R 37a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// value of pixel (x, y). 38a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 39a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// validPixelMask is a 16-bit mask where bit (1 << (x + y * 4)) indicates whether 40a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// the corresponding (x,y) pixel is valid. Invalid pixel color values are ignored when compressing. 41a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 42a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pOut is an ETC1 compressed version of the data. 43a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 44a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichvoid etc1_encode_block(const etc1_byte* pIn, etc1_uint32 validPixelMask, etc1_byte* pOut); 45a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 46a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Decode a block of pixels. 47a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 48a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pIn is an ETC1 compressed version of the data. 49a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 50a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pOut is a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a 51a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R 52a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// value of pixel (x, y). 53a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 54a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichvoid etc1_decode_block(const etc1_byte* pIn, etc1_byte* pOut); 55a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 56a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Return the size of the encoded image data (does not include size of PKM header). 57a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 58a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichetc1_uint32 etc1_get_encoded_data_size(etc1_uint32 width, etc1_uint32 height); 59a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 60a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Encode an entire image. 61a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pIn - pointer to the image data. Formatted such that 62a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pixel (x,y) is at pIn + pixelSize * x + stride * y; 63a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pOut - pointer to encoded data. Must be large enough to store entire encoded image. 64a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image. 65a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// returns non-zero if there is an error. 66a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 67a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichint etc1_encode_image(const etc1_byte* pIn, etc1_uint32 width, etc1_uint32 height, 68a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich etc1_uint32 pixelSize, etc1_uint32 stride, etc1_byte* pOut); 69a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 70a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Decode an entire image. 71a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pIn - pointer to encoded data. 72a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pOut - pointer to the image data. Will be written such that 73a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pixel (x,y) is at pIn + pixelSize * x + stride * y. Must be 74a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// large enough to store entire image. 75a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image. 76a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// returns non-zero if there is an error. 77a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 78a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichint etc1_decode_image(const etc1_byte* pIn, etc1_byte* pOut, 79a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich etc1_uint32 width, etc1_uint32 height, 80a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich etc1_uint32 pixelSize, etc1_uint32 stride); 81a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 82a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Size of a PKM header, in bytes. 83a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 84a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#define ETC_PKM_HEADER_SIZE 16 85a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 86a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Format a PKM header 87a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 88a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichvoid etc1_pkm_format_header(etc1_byte* pHeader, etc1_uint32 width, etc1_uint32 height); 89a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 90a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Check if a PKM header is correctly formatted. 91a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 92a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichetc1_bool etc1_pkm_is_valid(const etc1_byte* pHeader); 93a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 94a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Read the image width from a PKM header 95a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 96a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichetc1_uint32 etc1_pkm_get_width(const etc1_byte* pHeader); 97a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 98a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich// Read the image height from a PKM header 99a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 100a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevichetc1_uint32 etc1_pkm_get_height(const etc1_byte* pHeader); 101a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 102a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#ifdef __cplusplus 103a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich} 104a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#endif 105a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich 106a6276fdd4253c3a7150ab675678c750473ab6c45Jack Palevich#endif 107