/**
* Convert a point to a grid index.
*/
private int pointToGridIdx(Grid grid, float[] point)
{
int[] idx = new int[3];
float[] size = grid.getSize ();
for (int i = 0; i < 3; ++i) {
idx [i] = (int)Math.Floor ((point [i] - grid.getMin () [i]) / size [i]);
if (idx [i] >= grid.getDivision () [i]) {
idx [i] = grid.getDivision () [i] - 1;
}
}
return idx [0] + grid.getDivision () [0] * (idx [1] + grid.getDivision () [1] * idx [2]);
}
public SortableVertex[] sortVertices(Grid grid, float[] v)
{
// Prepare sort vertex array
int vc = v.Length / Mesh.CTM_POSITION_ELEMENT_COUNT;
SortableVertex[] sortVertices = new SortableVertex[vc];
for (int i = 0; i < vc; ++i) {
// Store vertex properties in the sort vertex array
float[] point = new float[]{v [i * 3], v [i * 3 + 1], v [i * 3 + 2]};
int p2g = pointToGridIdx (grid, point);
sortVertices [i] = new SortableVertex (v [i * 3], p2g, i);
}
// Sort vertices. The elements are first sorted by their grid indices, and
// scondly by their x coordinates.
Array.Sort (sortVertices);
return sortVertices;
}
/**
* Calculate various forms of derivatives in order to reduce data entropy.
*/
private int[] makeVertexDeltas(float[] vertices, SortableVertex[] sortVertices, Grid grid)
{
int vc = sortVertices.Length;
// Vertex scaling factor
float scale = 1.0f / vertexPrecision;
float prevGridIndex = 0x7fffffff;
int prevDeltaX = 0;
int[] intVertices = new int[vc * Mesh.CTM_POSITION_ELEMENT_COUNT];
for (int i = 0; i < vc; ++i) {
// Get grid box origin
int gridIdx = sortVertices [i].gridIndex;
float[] gridOrigin = CommonAlgorithm.gridIdxToPoint (grid, gridIdx);
// Get old vertex coordinate index (before vertex sorting)
int oldIdx = sortVertices [i].originalIndex;
// Store delta to the grid box origin in the integer vertex array. For the
// X axis (which is sorted) we also do the delta to the previous coordinate
// in the box.
int deltaX = (int)Math.Floor (scale * (vertices [oldIdx * 3] - gridOrigin [0]) + 0.5f);
if (gridIdx == prevGridIndex) {
intVertices [i * 3] = deltaX - prevDeltaX;
} else {
intVertices [i * 3] = deltaX;
}
intVertices [i * 3 + 1] = (int)Math.Floor (scale * (vertices [oldIdx * 3 + 1] - gridOrigin [1]) + 0.5f);
intVertices [i * 3 + 2] = (int)Math.Floor (scale * (vertices [oldIdx * 3 + 2] - gridOrigin [2]) + 0.5f);
prevGridIndex = gridIdx;
prevDeltaX = deltaX;
}
return intVertices;
}
private float[] readVertices(CtmInputStream input, Grid grid, int vcount, float precision)
{
checkTag(input.readLittleInt(), VERT);
int[] intVertices = input.readPackedInts(vcount, Mesh.CTM_POSITION_ELEMENT_COUNT, false);
checkTag(input.readLittleInt(), GIDX);
int[] gridIndices = input.readPackedInts(vcount, 1, false);
for (int i = 1; i < vcount; i++) {
gridIndices[i] += gridIndices[i - 1];
}
return CommonAlgorithm.restoreVertices(intVertices, gridIndices, grid, precision);
}
