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-rw-r--r--Runtime/Terrain/TerrainIndexGenerator.cpp379
1 files changed, 379 insertions, 0 deletions
diff --git a/Runtime/Terrain/TerrainIndexGenerator.cpp b/Runtime/Terrain/TerrainIndexGenerator.cpp
new file mode 100644
index 0000000..bcbc8d3
--- /dev/null
+++ b/Runtime/Terrain/TerrainIndexGenerator.cpp
@@ -0,0 +1,379 @@
+#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
generated by cgit v1.1-26-g67d0 at 2025-05-18 19:27:49 +0000