godot_voxel/streams/instance_data.h

#ifndef VOXEL_INSTANCE_DATA_H
#define VOXEL_INSTANCE_DATA_H

#include "../util/span.h"
#include <core/math/transform_3d.h>

namespace zylann::voxel {

// Stores data to pass around until it either gets saved or turned into actual instances
struct InstanceBlockData {
	struct InstanceData {
		Transform3D transform;
	};

	enum VoxelInstanceFormat {
		// Position is lossy-compressed based on the size of the block
		// - uint16_t x;
		// - uint16_t y;
		// - uint16_t z;
		//
		// Scale is uniform and is lossy-compressed to 256 values
		// - uint8_t scale;
		//
		// Rotation is a compressed quaternion with naive quantization of its members to 256 values
		// - uint8_t x;
		// - uint8_t y;
		// - uint8_t z;
		// - uint8_t w;
		FORMAT_SIMPLE_11B_V1 = 0
	};

	static const int POSITION_RESOLUTION = 65536;
	// Because position is quantized we need its range, but it cannot be zero so it may be clamped to this.
	static const float POSITION_RANGE_MINIMUM;

	static const int SIMPLE_11B_V1_SCALE_RESOLUTION = 256;
	static const int SIMPLE_11B_V1_QUAT_RESOLUTION = 256;
	// Because scale is quantized we need its range, but it cannot be zero so it may be clamped to this.
	static const float SIMPLE_11B_V1_SCALE_RANGE_MINIMUM;

	struct LayerData {
		uint16_t id;
		float scale_min;
		float scale_max;
		std::vector<InstanceData> instances;
	};

	float position_range;
	std::vector<LayerData> layers;

	void copy_to(InstanceBlockData &dst) const {
		// It's all POD so it should work for now
		dst = *this;
	}
};

bool serialize_instance_block_data(const InstanceBlockData &src, std::vector<uint8_t> &dst);
bool deserialize_instance_block_data(InstanceBlockData &dst, Span<const uint8_t> src);

} // namespace zylann::voxel

#endif // VOXEL_INSTANCE_DATA_H