Function astcenc_get_block_info

Source/astcenc_entry.cpp:1401–1517

See header for documentation. */

/* See header for documentation. */
astcenc_error astcenc_get_block_info(
	astcenc_context* ctxo,
	const uint8_t data[16],
	astcenc_block_info* info
) {
#if defined(ASTCENC_DECOMPRESS_ONLY)
	(void)ctxo;
	(void)data;
	(void)info;
	return ASTCENC_ERR_BAD_CONTEXT;
#else
	astcenc_contexti* ctx = &ctxo->context;

	// Decode the compressed data into a symbolic form
	symbolic_compressed_block scb;
	physical_to_symbolic(*ctx->bsd, data, scb);

	// Fetch the appropriate partition and decimation tables
	const block_size_descriptor& bsd = *ctx->bsd;

	// Start from a clean slate
	memset(info, 0, sizeof(*info));

	// Basic info we can always populate
	info->profile = ctx->config.profile;

	info->block_x = ctx->config.block_x;
	info->block_y = ctx->config.block_y;
	info->block_z = ctx->config.block_z;
	info->texel_count = bsd.texel_count;

	// Check for error blocks first
	info->is_error_block = scb.block_type == SYM_BTYPE_ERROR;
	if (info->is_error_block)
	{
		return ASTCENC_SUCCESS;
	}

	// Check for constant color blocks second
	info->is_constant_block = scb.block_type == SYM_BTYPE_CONST_F16 ||
	                          scb.block_type == SYM_BTYPE_CONST_U16;
	if (info->is_constant_block)
	{
		return ASTCENC_SUCCESS;
	}

	// Otherwise handle a full block ; known to be valid after conditions above have been checked
	unsigned int partition_count = scb.partition_count;
	const auto& pi = bsd.get_partition_info(partition_count, scb.partition_index);

	const block_mode& bm = bsd.get_block_mode(scb.block_mode);
	const decimation_info& di = bsd.get_decimation_info(bm.decimation_mode);

	info->weight_x = di.weight_x;
	info->weight_y = di.weight_y;
	info->weight_z = di.weight_z;

	info->is_dual_plane_block = bm.is_dual_plane != 0;