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// SPDX-License-Identifier: Apache-2.0
// ----------------------------------------------------------------------------
// Copyright 2021 Arm Limited
//
// 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 minimal example of using the astcenc library.
//
// This sample shows how to include the astcenc library in your CMake project
// as an external dependency, and how to compress and decompress images using
// the C library API.
//
// For sake of clarity the command line exposed by the sample is minimalistic,
// and the compression uses a fixed set of options, but the code is commented
// to indicate where extension would be possible. Errors handling points are
// detected and logged, but resources are not cleaned up on error paths to keep
// the sample control path simple, so resources will leak on error.
#include <stdio.h>
#include "astcenc.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
int main(int argc, char **argv)
{
// Parse command line
if (argc != 3)
{
printf("Usage:\n"
" %s <source> <dest>\n\n"
" <source> : Uncompressed LDR source image.\n"
" <dest> : Uncompressed LDR destination image (png).\n"
, argv[0]);
return 1;
}
// ------------------------------------------------------------------------
// For the purposes of this sample we hard-code the compressor settings
static const unsigned int thread_count = 1;
static const unsigned int block_x = 6;
static const unsigned int block_y = 6;
static const unsigned int block_z = 1;
static const astcenc_profile profile = ASTCENC_PRF_LDR;
static const float quality = ASTCENC_PRE_MEDIUM;
static const astcenc_swizzle swizzle {
ASTCENC_SWZ_R, ASTCENC_SWZ_G, ASTCENC_SWZ_B, ASTCENC_SWZ_A
};
// ------------------------------------------------------------------------
// Load input image, forcing 4 components
int image_x, image_y, image_c;
uint8_t *image_data = (uint8_t*)stbi_load(argv[1], &image_x, &image_y, &image_c, 4);
if (!image_data)
{
printf("Failed to load image \"%s\"\n", argv[1]);
return 1;
}
// Compute the number of ASTC blocks in each dimension
unsigned int block_count_x = (image_x + block_x - 1) / block_x;
unsigned int block_count_y = (image_y + block_y - 1) / block_y;
// ------------------------------------------------------------------------
// Initialize the default configuration for the block size and quality
astcenc_config config;
config.block_x = block_x;
config.block_y = block_y;
config.profile = profile;
astcenc_error status;
status = astcenc_config_init(profile, block_x, block_y, block_z, quality, 0, &config);
if (status != ASTCENC_SUCCESS)
{
printf("ERROR: Codec config init failed: %s\n", astcenc_get_error_string(status));
return 1;
}
// ... power users can customize any config settings after calling
// config_init() and before calling context alloc().
// ------------------------------------------------------------------------
// Create a context based on the configuration
astcenc_context* context;
status = astcenc_context_alloc(&config, thread_count, &context);
if (status != ASTCENC_SUCCESS)
{
printf("ERROR: Codec context alloc failed: %s\n", astcenc_get_error_string(status));
return 1;
}
// ------------------------------------------------------------------------
// Compress the image
astcenc_image image;
image.dim_x = image_x;
image.dim_y = image_y;
image.dim_z = 1;
image.data_type = ASTCENC_TYPE_U8;
uint8_t* slices = image_data;
image.data = reinterpret_cast<void**>(&slices);
// Space needed for 16 bytes of output per compressed block
size_t comp_len = block_count_x * block_count_y * 16;
uint8_t* comp_data = new uint8_t[comp_len];
status = astcenc_compress_image(context, &image, &swizzle, comp_data, comp_len, 0);
if (status != ASTCENC_SUCCESS)
{
printf("ERROR: Codec compress failed: %s\n", astcenc_get_error_string(status));
return 1;
}
// ... the comp_data array contains the raw compressed data you would pass
// to the graphics API, or pack into a wrapper format such as a KTX file.
// If using multithreaded compression to sequentially compress multiple
// images you should reuse the same context, calling the function
// astcenc_compress_reset() between each image in the series.
// ------------------------------------------------------------------------
// Decompress the image
// Note we just reuse the image structure to store the output here ...
status = astcenc_decompress_image(context, comp_data, comp_len, &image, &swizzle, 0);
if (status != ASTCENC_SUCCESS)
{
printf("ERROR: Codec decompress failed: %s\n", astcenc_get_error_string(status));
return 1;
}
// If using multithreaded decompression to sequentially decompress multiple
// images you should reuse the same context, calling the function
// astcenc_decompress_reset() between each image in the series.
// ------------------------------------------------------------------------
// Store the result back to disk
stbi_write_png(argv[2], image_x, image_y, 4, image_data, 4 * image_x);
// ------------------------------------------------------------------------
// Cleanup library resources
stbi_image_free(image_data);
astcenc_context_free(context);
delete[] comp_data;
return 0;
}
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