loadimage_astc.cpp

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//

// Copyright 2022 The ANGLE Project Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

//

// loadimage_astc.cpp: Decodes ASTC encoded textures.

#ifdef ANGLE_HAS_ASTCENC

#    include <astcenc.h>

#endif

#include "image_util/loadimage.h"

namespace angle

void LoadASTCToRGBA8Inner(size_t width,

                          size_t height,

                          size_t depth,

                          uint32_t blockWidth,

                          uint32_t blockHeight,

                          const uint8_t *input,

                          size_t inputRowPitch,

                          size_t inputDepthPitch,

                          uint8_t *output,

                          size_t outputRowPitch,

                          size_t outputDepthPitch)

#ifdef ANGLE_HAS_ASTCENC

    astcenc_config config;

    constexpr unsigned int kBlockZ = 1;

    const float kQuality               = ASTCENC_PRE_MEDIUM;

    constexpr astcenc_profile kProfile = ASTCENC_PRF_LDR;

    astcenc_error status;

    status = astcenc_config_init(kProfile, blockWidth, blockHeight, kBlockZ, kQuality,

                                 ASTCENC_FLG_DECOMPRESS_ONLY, &config);

    if (status != ASTCENC_SUCCESS)

        WARN() << "astcenc config init failed: " << astcenc_get_error_string(status);

        return;

    constexpr unsigned int kThreadCount = 1;

    astcenc_context *context;

    status = astcenc_context_alloc(&config, kThreadCount, &context);

    if (status != ASTCENC_SUCCESS)

        WARN() << "Could not allocate astcenc context: " << astcenc_get_error_string(status);

        return;

    // Compute the number of ASTC blocks in each dimension

    uint32_t blockCountX = (static_cast<uint32_t>(width) + config.block_x - 1) / config.block_x;

    uint32_t blockCountY = (static_cast<uint32_t>(height) + config.block_y - 1) / config.block_y;

    // Space needed for 16 bytes of output per compressed block

    size_t blockSize = blockCountX * blockCountY * 16;

    astcenc_image image;

    image.dim_x     = static_cast<uint32_t>(width);

    image.dim_y     = static_cast<uint32_t>(height);

    image.dim_z     = 1;

    image.data_type = ASTCENC_TYPE_U8;

    image.data      = reinterpret_cast<void **>(&output);

    constexpr astcenc_swizzle swizzle{ASTCENC_SWZ_R, ASTCENC_SWZ_G, ASTCENC_SWZ_B, ASTCENC_SWZ_A};

    status = astcenc_decompress_image(context, input, blockSize, &image, &swizzle, 0);

    if (status != ASTCENC_SUCCESS)

        WARN() << "astcenc decompress failed: " << astcenc_get_error_string(status);

    astcenc_context_free(context);

#else

    ERR() << "Trying to decode ASTC without having ASTC support built.";

#endif

}  // namespace angle