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75 lines
1.6 KiB
HLSL
75 lines
1.6 KiB
HLSL
/******************************************************************************/
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/*
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Project - MudBun
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Publisher - Long Bunny Labs
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http://LongBunnyLabs.com
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Author - Ming-Lun "Allen" Chou
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http://AllenChou.net
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*/
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/******************************************************************************/
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#ifndef MUDBUN_VOXEL_HASH_DEFS
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#define MUDBUN_VOXEL_HASH_DEFS
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#include "Math/Codec.cginc"
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#define kNullVoxelHashKey (0)
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#define kMaxVoxelHashCollisions (64) // (nodeHashTableSize)
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struct VoxelHashEntry
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{
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uint key;
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int iNode;
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};
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VoxelHashEntry init_voxel_hash_entry()
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{
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VoxelHashEntry entry;
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entry.key = kNullVoxelHashKey;
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entry.iNode = -1;
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return entry;
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}
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#ifdef MUDBUN_IS_COMPUTE_SHADER
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RWStructuredBuffer<VoxelHashEntry> nodeHashTable;
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#else
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StructuredBuffer<VoxelHashEntry> nodeHashTable;
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#endif
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int nodeHashTableSize;
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uint top_node_key(int3 iCenter)
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{
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iCenter = clamp(iCenter + 512, int3(0, 0, 0), int3(1023, 1023, 1023));
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return fnv_hash_concat(kFnvDefaultBasis, (uint(iCenter.x) << 21) | (uint(iCenter.y) << 11) | (uint(iCenter.z) << 1) | 1);
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}
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uint concat_node_key(uint key, uint3 coord)
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{
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return fnv_hash_concat(key, (coord.x << 16) | (coord.y << 8) | coord.z);
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}
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int look_up_node(uint key)
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{
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uint slot = key % nodeHashTableSize;
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int i = 0;
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while (i++ < kMaxVoxelHashCollisions)
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{
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uint entryKey = nodeHashTable[slot].key;
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if (entryKey == kNullVoxelHashKey)
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return -1;
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if (entryKey == key)
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return nodeHashTable[slot].iNode;
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slot = (slot + 1) % nodeHashTableSize;
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}
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return -1;
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}
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#endif
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