void OnRenderObject()
{
float camFarPlaneScale = 0.2f * 1000.0f / cam.farClipPlane;
CameraViewVolume viewVolume = cam.GetViewVolume(cam.farClipPlane * camFarPlaneScale);
Bounds volumeAABB = viewVolume.AABB;
float minX = volumeAABB.min.x;
float minZ = volumeAABB.min.z;
float maxX = volumeAABB.max.x;
float maxZ = volumeAABB.max.z;
float halfCellSizeX = 0.5f * baseSize;
float halfCellSizeZ = 0.5f * baseSize;
int minCellX = Mathf.FloorToInt((minX + halfCellSizeX) / baseSize) - 1;
int maxCellX = Mathf.FloorToInt((maxX + halfCellSizeX) / baseSize) + 1;
int minCellZ = Mathf.FloorToInt((minZ + halfCellSizeZ) / baseSize) - 1;
int maxCellZ = Mathf.FloorToInt((maxZ + halfCellSizeZ) / baseSize) + 1;
int minCellIndex = minCellX < minCellZ ? minCellX : minCellZ;
int maxCellIndex = maxCellX > maxCellZ ? maxCellX : maxCellZ;
GL.Begin(GL.LINES);
float startZ = minCellIndex * baseSize;
float endZ = (maxCellIndex + 1) * baseSize;
float startX = minCellIndex * baseSize;
float endX = (maxCellIndex + 1) * baseSize;
Vector3 yOffset = Vector3.up * transform.position.y;
for (int cell = minCellIndex; cell <= maxCellIndex; ++cell)
{
Vector3 xOffset = cell * Vector3.right * baseSize + yOffset;
GL.Vertex(xOffset + Vector3.forward * startZ);
GL.Vertex(xOffset + Vector3.forward * endZ);
Vector3 zOffset = cell * Vector3.forward * baseSize + yOffset;
GL.Vertex(zOffset + Vector3.right * startX);
GL.Vertex(zOffset + Vector3.right * endX);
}
GL.End();
}