/*
* child pointer | valid mask | nonleaf mask
* 16 8 8
*/
private void ExpandSVOAux(Node node, int nodeIndex, int level, List <int> svo, List <Node> svoNodes)
{
ChildDescriptor descriptor = new ChildDescriptor(svo[nodeIndex]);
node.children = new Node[8];
int pointer = descriptor.childPointer;
float half = node.size / 2f;
if (svoNodes[nodeIndex] == null)
{
svoNodes[nodeIndex] = node;
}
for (int childNum = 0; childNum < 8; childNum++)
{
if (descriptor.Valid(childNum))
{
bool leaf = descriptor.Leaf(childNum);
Node child = new Node(node.position + Constants.vfoffsets[childNum] * (float)(half), half, level + 1, leaf);
node.children[childNum] = child;
if (!leaf)
{
ExpandSVOAux(node.children[childNum], pointer++, level + 1, svo, svoNodes);
}
}
}
}
private void RayStep(List <int> svo, Vector3 rayOrigin, Vector3 rayDirection, List <Node> intersectedNodes, List <Node> allSvoNodes)
{
//Debug.Log("Tracing svo hierarchy\n" + allSvoNodes[])
//string debugStr = "";
//debugStr += string.Join("\n", svo.ConvertAll(code => new ChildDescriptor(code)));
//debugStr += "\nNeatly Printed Hierarchy:\n";
//debugStr += allSvoNodes[0].StringifyHierarchy();
//GUIUtility.systemCopyBuffer = debugStr;
int s_max = 23;
float epsilon = Mathf.Epsilon;
StackData[] stack = new StackData[s_max + 1];
float tx_coef = 1.0f / -Mathf.Abs(rayDirection.x);
float ty_coef = 1.0f / -Mathf.Abs(rayDirection.y);
float tz_coef = 1.0f / -Mathf.Abs(rayDirection.z);
float tx_bias = tx_coef * rayOrigin.x;
float ty_bias = ty_coef * rayOrigin.y;
float tz_bias = tz_coef * rayOrigin.z;
int octant_mask = 7;
if (rayDirection.x > 0.0f)
{
octant_mask ^= 1;
tx_bias = 3.0f * tx_coef - tx_bias;
}
if (rayDirection.y > 0.0f)
{
octant_mask ^= 2;
ty_bias = 3.0f * ty_coef - ty_bias;
}
if (rayDirection.z > 0.0f)
{
octant_mask ^= 4;
tz_bias = 3.0f * tz_coef - tz_bias;
}
float t_min = Mathf.Max(2.0f * tx_coef - tx_bias, 2.0f * ty_coef - ty_bias, 2.0f * tz_coef - tz_bias);
float t_max = Mathf.Min(tx_coef - tx_bias, ty_coef - ty_bias, tz_coef - tz_bias);
float h = t_max;
t_min = Mathf.Max(t_min, 0.0f);
t_max = Mathf.Min(t_max, 1.0f);
int parent = 0; // pointer to parent
int child_descriptor = 0; // invalid until fetched
int idx = 0;
Vector3 pos = new Vector3(1.0f, 1.0f, 1.0f); // position of first child of root
int scale = s_max - 1; // scale of "child" (22 at root)
float scale_exp2 = 0.5f; // exp2f(scale - s_max)
if (1.5f * tx_coef - tx_bias > t_min)
{
idx ^= 1; pos.x = 1.5f;
}
if (1.5f * ty_coef - ty_bias > t_min)
{
idx ^= 2; pos.y = 1.5f;
}
if (1.5f * tz_coef - tz_bias > t_min)
{
idx ^= 4; pos.z = 1.5f;
}
List <int> parentsVisited = new List <int>();
while (scale < s_max)
{
if (parent < allSvoNodes.Count)
{
//intersectedNodes.Add(allSvoNodes[parent]);
Vector3 nodePos = pos;
if ((octant_mask & 1) == 0)
{
nodePos.x = 3.0f - scale_exp2 - nodePos.x;
}
if ((octant_mask & 2) == 0)
{
nodePos.y = 3.0f - scale_exp2 - nodePos.y;
}
if ((octant_mask & 4) == 0)
{
nodePos.z = 3.0f - scale_exp2 - nodePos.z;
}
parentsVisited.Add(parent);
//intersectedNodes.Add(new Node(nodePos, scale_exp2, 24 - scale, false));
}
// Fetch child descriptor unless it is already valid.
if (child_descriptor == 0)
{
child_descriptor = svo[parent];
}
ChildDescriptor neatcd = new ChildDescriptor(child_descriptor);
// Determine maximum t-value of the cube by evaluating
// tx(), ty(), and tz() at its corner.
float tx_corner = pos.x * tx_coef - tx_bias;
float ty_corner = pos.y * ty_coef - ty_bias;
float tz_corner = pos.z * tz_coef - tz_bias;
float tc_max = Mathf.Min(tx_corner, ty_corner, tz_corner);
int child_shift = idx ^ octant_mask; // permute child slots based on the mirroring
int child_num = child_shift ^ 7; // Purely for seeing the index of the child in the debugger. Unused variable
int child_masks = child_descriptor << child_shift;
if ((child_masks & 0x8000) != 0 && t_min <= t_max)
{
// INTERSECT
// Intersect active t-span with the cube and evaluate
// tx(), ty(), and tz() at the center of the voxel.
float tv_max = Mathf.Min(t_max, tc_max);
float half = scale_exp2 * 0.5f;
float tx_center = half * tx_coef + tx_corner;
float ty_center = half * ty_coef + ty_corner;
float tz_center = half * tz_coef + tz_corner;
// Descend to the first child if the resulting t-span is non-empty.
if (t_min <= tv_max)
{
// Terminate if the corresponding bit in the non-leaf mask is not set.
if ((child_masks & 0x0080) == 0)
{
break; // at t_min (overridden with tv_min).
}
// PUSH
// Write current parent to the stack.
if (tc_max < h)
{
stack[scale] = new StackData(parent, t_max);
}
h = tc_max;
// Find child descriptor corresponding to the current voxel.
// child_descriptor format: first 16 bits is child pointer
// next 8 is valid, next 8 is leaf
int ofs = (child_descriptor >> 16); // child pointer
ofs += popc8(child_masks & 0x7F); // finds (bits - 1) of shifted non-leaf mask
parent = ofs;
// Select child voxel that the ray enters first.
idx = 0;
scale--;
scale_exp2 = half;
if (tx_center > t_min)
{
idx ^= 1; pos.x += scale_exp2;
}
if (ty_center > t_min)
{
idx ^= 2; pos.y += scale_exp2;
}
if (tz_center > t_min)
{
idx ^= 4; pos.z += scale_exp2;
}
// Update active t-span and invalidate cached child descriptor.
t_max = tv_max;
child_descriptor = 0;
continue;
}
}
// ADVANCE
// Step along the ray.
int step_mask = 0;
if (tx_corner <= tc_max)
{
step_mask ^= 1; pos.x -= scale_exp2;
}
if (ty_corner <= tc_max)
{
step_mask ^= 2; pos.y -= scale_exp2;
}
if (tz_corner <= tc_max)
{
step_mask ^= 4; pos.z -= scale_exp2;
}
// Update active t-span and flip bits of the child slot index.
t_min = tc_max;
idx ^= step_mask;
// Proceed with pop if the bit flips disagree with the ray direction.
if ((idx & step_mask) != 0)
{
// POP
// Find the highest differing bit between the two positions.
int differing_bits = 0;
if ((step_mask & 1) != 0)
{
differing_bits |= __float_as_int(pos.x) ^ __float_as_int(pos.x + scale_exp2);
}
if ((step_mask & 2) != 0)
{
differing_bits |= __float_as_int(pos.y) ^ __float_as_int(pos.y + scale_exp2);
}
if ((step_mask & 4) != 0)
{
differing_bits |= __float_as_int(pos.z) ^ __float_as_int(pos.z + scale_exp2);
}
scale = (__float_as_int((float)differing_bits) >> 23) - 127; // position of the highest bit
scale_exp2 = __int_as_float((scale - s_max + 127) << 23); // exp2f(scale - s_max)
// Restore parent voxel from the stack.
StackData stackEntry = stack[scale];
if (stackEntry != null)
{
parent = stackEntry.x;
t_max = stackEntry.y;
}
// Round cube position and extract child slot index.
int shx = __float_as_int(pos.x) >> scale;
int shy = __float_as_int(pos.y) >> scale;
int shz = __float_as_int(pos.z) >> scale;
pos.x = __int_as_float(shx << scale);
pos.y = __int_as_float(shy << scale);
pos.z = __int_as_float(shz << scale);
idx = (shx & 1) | ((shy & 1) << 1) | ((shz & 1) << 2);
// Prevent same parent from being stored again and invalidate cached child descriptor.
h = 0.0f;
child_descriptor = 0;
}
}
// Indicate miss if we are outside the octree.
if (scale >= s_max)
{
t_min = 2.0f;
}
// Undo mirroring of the coordinate system.
if ((octant_mask & 1) == 0)
{
pos.x = 3.0f - scale_exp2 - pos.x;
}
if ((octant_mask & 2) == 0)
{
pos.y = 3.0f - scale_exp2 - pos.y;
}
if ((octant_mask & 4) == 0)
{
pos.z = 3.0f - scale_exp2 - pos.z;
}
// Output results.
/* hit_t = t_min;
* hit_pos.x = fminf(fmaxf(p.x + t_min * d.x, pos.x + epsilon), pos.x + scale_exp2 - epsilon);
* hit_pos.y = fminf(fmaxf(p.y + t_min * d.y, pos.y + epsilon), pos.y + scale_exp2 - epsilon);
* hit_pos.z = fminf(fmaxf(p.z + t_min * d.z, pos.z + epsilon), pos.z + scale_exp2 - epsilon);
* hit_parent = parent;
* hit_idx = idx ˆ octant_mask ˆ 7;
* hit_scale = scale;*/
//Vector3 hit_pos = new Vector3()
if (scale >= s_max)
{
}
else
{
Debug.Log("Hit_t: " + t_min);
Debug.Log("Hit parents: " + string.Join(", ", parentsVisited));
Debug.Log("Hit idx: " + (idx ^ octant_mask ^ 7));
intersectedNodes.Add(allSvoNodes[parent].children[idx ^ octant_mask ^ 7]);
}
}