2016-07-07 17:42:26 +10:00

97 lines
2.9 KiB
C#

// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
#if OCCLUSION
using System;
using ClassicalSharp.GraphicsAPI;
namespace ClassicalSharp {
public partial class ChunkMeshBuilder {
unsafe int ComputeOcclusion() {
int* didFlags = stackalloc int[chunkSize2];
OpenTK.MemUtils.memset( (IntPtr)didFlags, 0x00, 0, chunkSize2 * sizeof( int ) );
int* stack = stackalloc int[chunkSize3 * 4];
int i = 0;
bool solidX = true, solidY = true, solidZ = true;
for( int y = 0; y < 16; y++ ) {
for( int z = 0; z < 16; z++ ) {
int flagIndex = (y << 4) | z;
int chunkIndex = (y + 1) * extChunkSize2 + (z + 1) * extChunkSize + (0 + 1);
for( int x = 0; x < 16; x++ ) {
byte block = chunk[chunkIndex];
if( info.IsOpaque[block] ) {
didFlags[flagIndex] |= (1 << x);
} else if( (didFlags[flagIndex] & (1 << x)) == 0 ) {
FloodFill( didFlags, stack, i, ref solidX, ref solidY, ref solidZ );
}
i++;
chunkIndex++;
}
}
}
return (solidX ? 0x1 : 0) | (solidZ ? 0x2 : 0) | (solidY ? 0x4 : 0);
}
unsafe void FloodFill( int* didFlags, int* stack, int startIndex,
ref bool solidX, ref bool solidY, ref bool solidZ ) {
int index = 0;
stack[index++] = startIndex;
bool tX0 = false, tX1 = false, tY0 = false,
tY1 = false, tZ0 = false, tZ1 = false;
while( index > 0 ) {
int bIndex = stack[--index];
int x = (bIndex & 0xF);
int z = ((bIndex >> 4) & 0xF);
int y = ((bIndex >> 8) & 0xF);
int flagIndex = (y << 4) | z;
didFlags[flagIndex] |= (1 << x);
int chunkIndex = (y + 1) * extChunkSize2 + (z + 1) * extChunkSize + (x + 1);
byte block = chunk[chunkIndex];
if( !info.IsOpaque[block] ) {
if( x == 0 )
tX0 = true;
else if( (didFlags[flagIndex] & (1 << (x - 1))) == 0 )
stack[index++] = bIndex - 1;
if( x == 15 )
tX1 = true;
else if( (didFlags[flagIndex] & (1 << (x + 1))) == 0 )
stack[index++] = bIndex + 1;
if( z == 0 )
tZ0 = true;
else if( (didFlags[flagIndex - 1] & (1 << x)) == 0 )
stack[index++] = bIndex - 16;
if( z == 15 )
tZ1 = true;
else if( (didFlags[flagIndex + 1] & (1 << x)) == 0 )
stack[index++] = bIndex + 16;
}
if( !info.IsOpaqueY[block] ) {
if( y == 0 )
tY0 = true;
else if( (didFlags[flagIndex - 16] & (1 << x)) == 0
&& !info.IsOpaqueY[chunk[chunkIndex - extChunkSize2]] )
stack[index++] = bIndex - 256;
if( y == 15 )
tY1 = true;
else if( (didFlags[flagIndex + 16] & (1 << x)) == 0
&& !info.IsOpaqueY[chunk[chunkIndex + extChunkSize2]] )
stack[index++] = bIndex + 256;
}
}
if( tX0 && tX1 ) solidX = false;
if( tY0 && tY1 ) solidY = false;
if( tZ0 && tZ1 ) solidZ = false;
}
}
}
#endif