public static MeshDetails BuildMesh(float[,] noiseArea, int lod, AreaDetails areaDetails)
{
int lodIncrement = lod == 0 ? 1 : lod * 2;
int verticesPerLine = areaDetails.verticesPerLine;
Vector2 topLeftCorner = new Vector2(-1, 1) * areaDetails.resolution / 2f;
MeshDetails meshDetails = new MeshDetails(verticesPerLine, areaDetails.useFlatshading, lodIncrement);
int[,] vertexIndexes = new int[verticesPerLine, verticesPerLine];
int meshVertexIndex = 0;
int outsideVertexIndex = -1;
for (int yIndex = 0; yIndex < verticesPerLine; yIndex++)
{
for (int xIndex = 0; xIndex < verticesPerLine; xIndex++)
{
bool isOutsideVertex = yIndex == 0 || xIndex == 0 || yIndex == verticesPerLine - 1 || xIndex == verticesPerLine - 1;
bool isUselessVertex = xIndex > 2 && xIndex < verticesPerLine - 3 && yIndex > 2 && yIndex < verticesPerLine - 3 && ((xIndex - 2) % lodIncrement != 0 || (yIndex - 2) % lodIncrement != 0);
if (isOutsideVertex)
{
vertexIndexes[xIndex, yIndex] = outsideVertexIndex;
outsideVertexIndex--;
}
else if (!isUselessVertex)
{
vertexIndexes[xIndex, yIndex] = meshVertexIndex;
meshVertexIndex++;
}
}
}
for (int yIndex = 0; yIndex < verticesPerLine; yIndex++)
{
for (int xIndex = 0; xIndex < verticesPerLine; xIndex++)
{
bool isUselessVertex = xIndex > 2 && xIndex < verticesPerLine - 3 && yIndex > 2 && yIndex < verticesPerLine - 3 && ((xIndex - 2) % lodIncrement != 0 || (yIndex - 2) % lodIncrement != 0);
if (!isUselessVertex)
{
bool isOutsideVertex = yIndex == 0 || xIndex == 0 || yIndex == verticesPerLine - 1 || xIndex == verticesPerLine - 1;
bool isFrontierVertex = (yIndex == 1 || yIndex == verticesPerLine - 2 || xIndex == 1 || xIndex == verticesPerLine - 2) && !isOutsideVertex;
bool isMainVertex = (xIndex - 2) % lodIncrement == 0 && (yIndex - 2) % lodIncrement == 0 && !isOutsideVertex && !isFrontierVertex;
bool isInsideVertex = (yIndex == 2 || yIndex == verticesPerLine - 3 || xIndex == 2 || xIndex == verticesPerLine - 3) && !isOutsideVertex && !isFrontierVertex && !isMainVertex;
int vertexIndex = vertexIndexes[xIndex, yIndex];
Vector2 uv = new Vector2(xIndex - 1, yIndex - 1) / (verticesPerLine - 3);
Vector2 vertexCoords = topLeftCorner + new Vector2(uv.x, -uv.y) * areaDetails.resolution;
float height = noiseArea[xIndex, yIndex];
if (isInsideVertex)
{
bool isVertical = xIndex == 2 || xIndex == verticesPerLine - 3;
int distanceToMainVertexA = (isVertical ? yIndex - 2 : xIndex - 2) % lodIncrement;
int distanceToMainVertexB = lodIncrement - distanceToMainVertexA;
float distancePercentage = distanceToMainVertexA / (float)lodIncrement;
float heightVertexA = noiseArea[isVertical ? xIndex : xIndex - distanceToMainVertexA, isVertical ? yIndex - distanceToMainVertexA : yIndex];
float heightVertexB = noiseArea[isVertical ? xIndex : xIndex + distanceToMainVertexB, isVertical ? yIndex + distanceToMainVertexB : yIndex];
height = heightVertexA * (1 - distancePercentage) + heightVertexB * distancePercentage;
}
meshDetails.AddVertex(new Vector3(vertexCoords.x, height, vertexCoords.y), uv, vertexIndex);
bool createTriangle = xIndex < verticesPerLine - 1 && yIndex < verticesPerLine - 1 && (!isInsideVertex || (xIndex != 2 && yIndex != 2));
if (createTriangle)
{
int currentIncrement = (isMainVertex && xIndex != verticesPerLine - 3 && yIndex != verticesPerLine - 3) ? lodIncrement : 1;
int vertexAIndex = vertexIndexes[xIndex, yIndex];
int vertexBIndex = vertexIndexes[xIndex + currentIncrement, yIndex];
int vertexCIndex = vertexIndexes[xIndex, yIndex + currentIncrement];
int vertexDIndex = vertexIndexes[xIndex + currentIncrement, yIndex + currentIncrement];
meshDetails.AddTriangle(vertexAIndex, vertexDIndex, vertexCIndex);
meshDetails.AddTriangle(vertexDIndex, vertexAIndex, vertexBIndex);
}
}
}
}
meshDetails.BuildLighting();
return(meshDetails);
}