// Copyright 2009 Google Inc. | |
// | |
// Licensed under the Apache License, Version 2.0 (the "License"); | |
// you may not use this file except in compliance with the License. | |
// You may obtain a copy of the License at | |
// | |
// http://www.apache.org/licenses/LICENSE-2.0 | |
// | |
// Unless required by applicable law or agreed to in writing, software | |
// distributed under the License is distributed on an "AS IS" BASIS, | |
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
// See the License for the specific language governing permissions and | |
// limitations under the License. | |
#ifndef __etc1_h__ | |
#define __etc1_h__ | |
#define ETC1_ENCODED_BLOCK_SIZE 8 | |
#define ETC1_DECODED_BLOCK_SIZE 48 | |
#ifndef ETC1_RGB8_OES | |
#define ETC1_RGB8_OES 0x8D64 | |
#endif | |
typedef unsigned char etc1_byte; | |
typedef int etc1_bool; | |
typedef unsigned int etc1_uint32; | |
#ifdef __cplusplus | |
extern "C" { | |
#endif | |
// Encode a block of pixels. | |
// | |
// pIn is a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a | |
// 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R | |
// value of pixel (x, y). | |
// | |
// validPixelMask is a 16-bit mask where bit (1 << (x + y * 4)) indicates whether | |
// the corresponding (x,y) pixel is valid. Invalid pixel color values are ignored when compressing. | |
// | |
// pOut is an ETC1 compressed version of the data. | |
void etc1_encode_block(const etc1_byte* pIn, etc1_uint32 validPixelMask, etc1_byte* pOut); | |
// Decode a block of pixels. | |
// | |
// pIn is an ETC1 compressed version of the data. | |
// | |
// pOut is a pointer to a ETC_DECODED_BLOCK_SIZE array of bytes that represent a | |
// 4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R | |
// value of pixel (x, y). | |
void etc1_decode_block(const etc1_byte* pIn, etc1_byte* pOut); | |
// Return the size of the encoded image data (does not include size of PKM header). | |
etc1_uint32 etc1_get_encoded_data_size(etc1_uint32 width, etc1_uint32 height); | |
// Encode an entire image. | |
// pIn - pointer to the image data. Formatted such that | |
// pixel (x,y) is at pIn + pixelSize * x + stride * y; | |
// pOut - pointer to encoded data. Must be large enough to store entire encoded image. | |
// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image. | |
// returns non-zero if there is an error. | |
int etc1_encode_image(const etc1_byte* pIn, etc1_uint32 width, etc1_uint32 height, | |
etc1_uint32 pixelSize, etc1_uint32 stride, etc1_byte* pOut); | |
// Decode an entire image. | |
// pIn - pointer to encoded data. | |
// pOut - pointer to the image data. Will be written such that | |
// pixel (x,y) is at pIn + pixelSize * x + stride * y. Must be | |
// large enough to store entire image. | |
// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image. | |
// returns non-zero if there is an error. | |
int etc1_decode_image(const etc1_byte* pIn, etc1_byte* pOut, | |
etc1_uint32 width, etc1_uint32 height, | |
etc1_uint32 pixelSize, etc1_uint32 stride); | |
// Size of a PKM header, in bytes. | |
#define ETC_PKM_HEADER_SIZE 16 | |
// Format a PKM header | |
void etc1_pkm_format_header(etc1_byte* pHeader, etc1_uint32 width, etc1_uint32 height); | |
// Check if a PKM header is correctly formatted. | |
etc1_bool etc1_pkm_is_valid(const etc1_byte* pHeader); | |
// Read the image width from a PKM header | |
etc1_uint32 etc1_pkm_get_width(const etc1_byte* pHeader); | |
// Read the image height from a PKM header | |
etc1_uint32 etc1_pkm_get_height(const etc1_byte* pHeader); | |
#ifdef __cplusplus | |
} | |
#endif | |
#endif |