Function load_image_block

Source/astcenc_image.cpp:162–275

See header for documentation. */

/* See header for documentation. */
void load_image_block(
	astcenc_profile decode_mode,
	const astcenc_image& img,
	image_block& blk,
	const block_size_descriptor& bsd,
	size_t pos_x,
	size_t pos_y,
	size_t pos_z,
	const astcenc_swizzle& swz
) {
	size_t size_x = img.dim_x;
	size_t size_y = img.dim_y;
	size_t size_z = img.dim_z;

	blk.pos_x = pos_x;
	blk.pos_y = pos_y;
	blk.pos_z = pos_z;

	// True if any non-identity swizzle
	bool needs_swz = (swz.r != ASTCENC_SWZ_R) || (swz.g != ASTCENC_SWZ_G) ||
	                 (swz.b != ASTCENC_SWZ_B) || (swz.a != ASTCENC_SWZ_A);

	vfloat4 data_min(1e38f);
	vfloat4 data_mean(0.0f);
	vfloat4 data_mean_scale(1.0f / static_cast<float>(bsd.texel_count));
	vfloat4 data_max(-1e38f);
	vmask4 grayscalev(true);
	size_t idx = 0;

	// This works because we impose the same choice everywhere during encode
	uint8_t rgb_lns = (decode_mode == ASTCENC_PRF_HDR) ||
	                  (decode_mode == ASTCENC_PRF_HDR_RGB_LDR_A) ? 1 : 0;
	uint8_t a_lns = decode_mode == ASTCENC_PRF_HDR ? 1 : 0;
	vint4 use_lns(rgb_lns, rgb_lns, rgb_lns, a_lns);
	vmask4 lns_mask = use_lns != vint4::zero();

	// Set up the function pointers for loading pipeline as needed
	pixel_loader loader = load_texel_u8;
	if (img.data_type == ASTCENC_TYPE_F16)
	{
		loader = load_texel_f16;
	}
	else if  (img.data_type == ASTCENC_TYPE_F32)
	{
		loader = load_texel_f32;
	}

	pixel_swizzler swizzler = swz_texel_skip;
	if (needs_swz)
	{
		swizzler = swz_texel;
	}

	pixel_converter converter = encode_texel_unorm;
	if (any(lns_mask))
	{
		converter = encode_texel_lns;
	}