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|
#include "UnityPrefix.h"
#include "TerrainIndexGenerator.h"
#if ENABLE_TERRAIN
#include "Runtime/Graphics/TriStripper.h"
#include "Runtime/Filters/Mesh/LodMesh.h"
#include "Runtime/Terrain/Heightmap.h"
static unsigned int AddSliverTriangles (unsigned int *triangles, unsigned int index, int direction, int edgeMask);
static unsigned int AddSliverCorner (unsigned int* triangles, unsigned int index, int direction, int edgeMask);
static void FlipTriangle (unsigned int *triangles, unsigned int index);
static unsigned int AddQuad (unsigned int *triangles, unsigned int index, int xBase, int yBase);
struct CachedStrip {
unsigned int count;
unsigned short* triangles;
CachedStrip() {count = 0; triangles = NULL;}
~CachedStrip() { if(triangles) delete[] triangles;}
};
static CachedStrip gCachedStrips[16];
unsigned int *TerrainIndexGenerator::GetIndexBuffer (int edgeMask, unsigned int &count, int stride)
{
unsigned int *triangles = new unsigned int[(kPatchSize) * (kPatchSize) * 6];
unsigned int index = 0;
int size = kPatchSize;
int minX = 0;
int minY = 0;
int maxX = kPatchSize-1;
int maxY = kPatchSize-1;
if((edgeMask & kDirectionLeftFlag) == 0)
{
minX+=1;
index = AddSliverTriangles (triangles, index, kDirectionLeft, edgeMask);
}
if((edgeMask & kDirectionRightFlag) == 0)
{
maxX-=1;
index = AddSliverTriangles (triangles, index, kDirectionRight, edgeMask);
}
if((edgeMask & kDirectionUpFlag) == 0)
{
maxY-=1;
index = AddSliverTriangles (triangles, index, kDirectionUp, edgeMask);
}
if((edgeMask & kDirectionDownFlag) == 0)
{
minY+=1;
index = AddSliverTriangles (triangles, index, kDirectionDown, edgeMask);
}
if((edgeMask & kDirectionLeftFlag) == 0 || (edgeMask & kDirectionUpFlag) == 0)
index = AddSliverCorner (triangles, index, kDirectionLeftUp, edgeMask);
if((edgeMask & kDirectionRightFlag) == 0 || (edgeMask & kDirectionUpFlag) == 0)
index = AddSliverCorner (triangles, index, kDirectionRightUp, edgeMask);
if((edgeMask & kDirectionLeftFlag) == 0 || (edgeMask & kDirectionDownFlag) == 0)
index = AddSliverCorner (triangles, index, kDirectionLeftDown, edgeMask);
if((edgeMask & kDirectionRightFlag) == 0 || (edgeMask & kDirectionDownFlag) == 0)
index = AddSliverCorner (triangles, index, kDirectionRightDown, edgeMask);
for (int y=minY;y<maxY;y++)
{
for (int x=minX;x<maxX;x++)
{
// For each grid cell output two triangles
triangles[index++] = y + (x * size);
triangles[index++] = (y+1) + x * size;
triangles[index++] = (y+1) + (x + 1) * size;
triangles[index++] = y + x * size;
triangles[index++] = (y+1) + (x + 1) * size;
triangles[index++] = y + (x + 1) * size;
}
}
count = index;
return triangles;
}
unsigned short *TerrainIndexGenerator::GetOptimizedIndexStrip (int edgeMask, unsigned int &count)
{
edgeMask &= kDirectionDirectNeighbourMask;
if (gCachedStrips[edgeMask].triangles == NULL)
{
unsigned int *triangles = GetIndexBuffer (edgeMask, count, 0);
Mesh::TemporaryIndexContainer newStrip;
Stripify ((const UInt32*)triangles, count, newStrip);
delete[] triangles;
count = newStrip.size();
unsigned short *strip = new unsigned short[count];
for(int i=0;i<count;i++)
strip[i] = newStrip[i];
gCachedStrips[edgeMask].count = count;
gCachedStrips[edgeMask].triangles = strip;
}
count = gCachedStrips[edgeMask].count;
return gCachedStrips[edgeMask].triangles;
}
static void FlipTriangle (unsigned int *triangles, unsigned int index)
{
int temp = triangles[index];
triangles[index] = triangles[index+1];
triangles[index+1] = temp;
}
static unsigned int AddQuad (unsigned int *triangles, unsigned int index, int xBase, int yBase)
{
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 1);
triangles[index++] = (xBase + 1) * kPatchSize + (yBase + 1);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + 1) * kPatchSize + (yBase + 1);
triangles[index++] = (xBase + 1) * kPatchSize + (yBase + 0);
return index;
}
static unsigned int AddSliverCorner (unsigned int* triangles, unsigned int index, int direction, int edgeMask)
{
int xBase, yBase, ox, oy;
bool flip = false;
int vMask = 0;
int hMask = 0;
if (direction == kDirectionLeftDown)
{
xBase = 1;
yBase = 1;
ox = 1;
oy = 1;
flip = false;
hMask = 1 << kDirectionLeft;
vMask = 1 << kDirectionDown;
}
else if (direction == kDirectionRightDown)
{
xBase = kPatchSize-2;
yBase = 1;
ox = -1;
oy = 1;
flip = true;
hMask = 1 << kDirectionRight;
vMask = 1 << kDirectionDown;
}
else if (direction == kDirectionLeftUp)
{
xBase = 1;
yBase = kPatchSize-2;
ox = 1;
oy = -1;
flip = true;
hMask = 1 << kDirectionLeft;
vMask = 1 << kDirectionUp;
}
else
{
xBase = kPatchSize-2;
yBase = kPatchSize-2;
ox = -1;
oy = -1;
flip = false;
hMask = 1 << kDirectionRight;
vMask = 1 << kDirectionUp;
}
int mask = 0;
if ((hMask & edgeMask) != 0)
mask |= 1;
if ((vMask & edgeMask) != 0)
mask |= 2;
// Both edges are tesselated
// Vertical edge is tesselated
if (mask == 1)
{
// Stitch big down and small up
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase + 0);
// rigth up small
triangles[index++] = (xBase + ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + ox) * kPatchSize + (yBase + 0);
// Down Big span
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase - oy);
if (flip)
{
FlipTriangle(triangles, index - 9);
FlipTriangle(triangles, index - 6);
FlipTriangle(triangles, index - 3);
}
}
// Horizontal edge is tesselated
else if (mask == 2)
{
// Left up small
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + oy);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase + oy);
// Left Big span
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase + oy);
// Stitch right-down and big left span
triangles[index++] = (xBase - ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase - oy);
if (flip)
{
FlipTriangle(triangles, index - 9);
FlipTriangle(triangles, index - 6);
FlipTriangle(triangles, index - 3);
}
}
// Nothing tesselated
else
{
// Left up small
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase + oy);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + oy);
// right up small
triangles[index++] = (xBase + ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + ox) * kPatchSize + (yBase + 0);
// Left Big span
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase + oy);
// Down Big span
triangles[index++] = (xBase + 0) * kPatchSize + (yBase + 0);
triangles[index++] = (xBase + ox) * kPatchSize + (yBase - oy);
triangles[index++] = (xBase - ox) * kPatchSize + (yBase - oy);
if (flip)
{
FlipTriangle(triangles, index - 12);
FlipTriangle(triangles, index - 9);
FlipTriangle(triangles, index - 6);
FlipTriangle(triangles, index - 3);
}
}
return index;
}
static unsigned int AddSliverTriangles (unsigned int *triangles, unsigned int index, int direction, int edgeMask)
{
int directionMask = 1 << direction;
if ((edgeMask & directionMask) != 0)
{
for (int y=2;y<kPatchSize-3;y++)
{
if (direction == kDirectionLeft)
index = AddQuad(triangles, index, 0, y);
else if (direction == kDirectionRight)
index = AddQuad(triangles, index, kPatchSize - 2, y);
else if (direction == kDirectionUp)
index = AddQuad(triangles, index, y, kPatchSize - 2);
else if (direction == kDirectionDown)
index = AddQuad(triangles, index, y, 0);
}
}
else
{
for (int i=2;i<kPatchSize-3;i+=2)
{
if (direction == kDirectionLeft)
{
int x = 0;
int y = i;
// fixup bottom
triangles[index++] = (x + 1) * kPatchSize + (y + 0);
triangles[index++] = (x + 0) * kPatchSize + (y + 0);
triangles[index++] = (x + 1) * kPatchSize + (y + 1);
// Big span
triangles[index++] = (x + 0) * kPatchSize + (y + 0);
triangles[index++] = (x + 0) * kPatchSize + (y + 2);
triangles[index++] = (x + 1) * kPatchSize + (y + 1);
// fixup top
triangles[index++] = (x + 0) * kPatchSize + (y + 2);
triangles[index++] = (x + 1) * kPatchSize + (y + 2);
triangles[index++] = (x + 1) * kPatchSize + (y + 1);
}
else if (direction == kDirectionRight)
{
int x = kPatchSize - 1;
int y = i;
// fixup bottom
triangles[index++] = (x - 1) * kPatchSize + (y + 0);
triangles[index++] = (x - 1) * kPatchSize + (y + 1);
triangles[index++] = (x - 0) * kPatchSize + (y + 0);
// Big span
triangles[index++] = (x - 0) * kPatchSize + (y + 0);
triangles[index++] = (x - 1) * kPatchSize + (y + 1);
triangles[index++] = (x - 0) * kPatchSize + (y + 2);
// fixup top
triangles[index++] = (x - 0) * kPatchSize + (y + 2);
triangles[index++] = (x - 1) * kPatchSize + (y + 1);
triangles[index++] = (x - 1) * kPatchSize + (y + 2);
}
else if (direction == kDirectionDown)
{
int x = i;
int y = 0;
// fixup bottom
triangles[index++] = (x + 0) * kPatchSize + (y + 0);
triangles[index++] = (x + 0) * kPatchSize + (y + 1);
triangles[index++] = (x + 1) * kPatchSize + (y + 1);
// Big span
triangles[index++] = (x + 1) * kPatchSize + (y + 1);
triangles[index++] = (x + 2) * kPatchSize + (y + 0);
triangles[index++] = (x + 0) * kPatchSize + (y + 0);
// fixup top
triangles[index++] = (x + 2) * kPatchSize + (y + 0);
triangles[index++] = (x + 1) * kPatchSize + (y + 1);
triangles[index++] = (x + 2) * kPatchSize + (y + 1);
}
else
{
int x = i;
int y = kPatchSize - 1;
// fixup bottom
triangles[index++] = (x + 0) * kPatchSize + (y - 0);
triangles[index++] = (x + 1) * kPatchSize + (y - 1);
triangles[index++] = (x + 0) * kPatchSize + (y - 1);
// Big span
triangles[index++] = (x + 1) * kPatchSize + (y - 1);
triangles[index++] = (x + 0) * kPatchSize + (y - 0);
triangles[index++] = (x + 2) * kPatchSize + (y - 0);
// fixup top
triangles[index++] = (x + 2) * kPatchSize + (y - 0);
triangles[index++] = (x + 2) * kPatchSize + (y - 1);
triangles[index++] = (x + 1) * kPatchSize + (y - 1);
}
}
}
return index;
}
#endif // ENABLE_TERRAIN
|
