| // 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. |
| |
| #pragma once |
| |
| #define MAX_ETC_SUPPORTED 12 |
| |
| #define ETC1_ENCODED_BLOCK_SIZE 8 |
| #define ETC1_DECODED_BLOCK_SIZE 48 |
| #define ETC2_DECODED_RGB8A1_BLOCK_SIZE 64 |
| #define EAC_ENCODE_ALPHA_BLOCK_SIZE 8 |
| #define EAC_DECODED_ALPHA_BLOCK_SIZE 16 |
| #define EAC_ENCODE_R11_BLOCK_SIZE 8 |
| #define EAC_DECODED_R11_BLOCK_SIZE 64 |
| #define EAC_DECODED_RG11_BLOCK_SIZE (EAC_DECODED_R11_BLOCK_SIZE*2) |
| |
| #ifndef ETC1_RGB8_OES |
| #define ETC1_RGB8_OES 0x8D64 |
| #endif |
| |
| typedef unsigned char etc1_byte; |
| typedef int etc1_bool; |
| typedef unsigned int etc1_uint32; |
| |
| enum ETC2ImageFormat { |
| EtcRGB8, EtcRGBA8, EtcR11, EtcSignedR11, EtcRG11, EtcSignedRG11, EtcRGB8A1 |
| }; |
| |
| #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 rgb pixels. |
| // |
| // pIn is an ETC2 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 etc2_decode_rgb_block(const etc1_byte* pIn, bool isPunchthroughAlpha, etc1_byte* pOut); |
| |
| // Decode a block of single channel pixels |
| // This is used when decoding the alpha channel of RGBA8_ETC2_EAC format, or |
| // when decoding R11_EAC format |
| // decodedElementBytes: number of bits per element after decoding. |
| // For RGBA8_ETC2_EAC it must be 1, for R11_EAC it must be 2 |
| |
| void eac_decode_single_channel_block(const etc1_byte* pIn, |
| int decodedElementBytes, bool isSigned, |
| 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); |
| |
| etc1_uint32 etc_get_encoded_data_size(ETC2ImageFormat format, etc1_uint32 width, |
| etc1_uint32 height); |
| etc1_uint32 etc_get_decoded_pixel_size(ETC2ImageFormat format); |
| |
| // 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=3 for rgb images, pixelSize=4 for images with alpha channel) |
| // returns non-zero if there is an error. |
| |
| int etc2_decode_image(const etc1_byte* pIn, ETC2ImageFormat format, |
| etc1_byte* pOut, |
| etc1_uint32 width, etc1_uint32 height, |
| 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 |