mirror of
https://github.com/scratchfoundation/bgfx.git
synced 2024-11-24 08:38:32 -05:00
114 lines
3.8 KiB
C
114 lines
3.8 KiB
C
// 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.
|
|
|
|
//////////////////////////////////////////////////////////////////////////////////////////
|
|
|
|
// This is a fork of the AOSP project ETC1 codec. The original code can be found
|
|
// at the following web site:
|
|
// https://android.googlesource.com/platform/frameworks/native/+/master/opengl/libs/ETC1/
|
|
|
|
//////////////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#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
|