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voxel-raycaster
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Worked out a bit more of the traversal. Up to the point of assessing the situation with intersection_t updating

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master
MitchellHansen 7 years ago
parent 3f09515c0a
commit 513a827645
2 changed files with 60 additions and 97 deletions
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1
include/map/Octree.h
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@ -8,6 +8,7 @@ struct OctState {
int parent_stack_position = 0;
uint64_t parent_stack[32] = { 0 };
uint64_t parent_stack_index[32] = { 0 };
uint8_t scale = 0;
uint8_t idx_stack[32] = { 0 };

154
src/map/Octree.cpp
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@ -53,7 +53,7 @@ OctState Octree::GetVoxel(sf::Vector3i position) {
//PrettyPrintUINT64(head);
state.parent_stack[state.parent_stack_position] = head;
state.parent_stack_index[state.parent_stack_position] = current_index;
// Set our initial dimension and the position at the corner of the oct to keep track of our position
int dimension = oct_dimensions;
@ -136,7 +136,7 @@ OctState Octree::GetVoxel(sf::Vector3i position) {
// Increment the parent stack position and put the new oct node as the parent
state.parent_stack_position++;
state.parent_stack[state.parent_stack_position] = head;
state.parent_stack_index[state.parent_stack_position] = current_index;
}
else {
// If the oct was not valid, then no CP's exists any further
@ -259,10 +259,6 @@ std::tuple<uint64_t, uint64_t> Octree::GenerationRecursion(char* data, sf::Vecto
}
//for (int i = 0; i < descriptor_position_array.size(); i++) {
// std::get<1>(descriptor_position_array.at(i)) = descriptor_buffer_position - i;
//}
unsigned int far_pointer_count = 0;
// If looking "up" to zero, the far ptr is entered first before the cp block. Get it's position
@ -474,15 +470,17 @@ std::vector<std::tuple<sf::Vector3i, char>> Octree::CastRayOctree(
}
traversal_state.idx_stack[traversal_state.scale] ^= this_face_mask;
// Mask index is the 1D index'd value of the idx for interaction with the valid / leaf masks
int mask_index = traversal_state.idx_stack[traversal_state.scale];
// Whether or not the next oct we want to enter in the current CD's valid mask is 1 or 0
bool is_valid = (traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & mask_8[mask_index];
// Check to see if the idx increased or decreased
// If it decreased
// Pop up the stack until the oct that the idx flip is valid and we landed on a valid oct
while (traversal_state.idx_stack[traversal_state.scale] < prev_val ||
// This will endless loop if we hit the empty portion of an octree and cant find a leaf until the we go OOB
!((traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & Octree::mask_8[mask_index])
) {
while (mask_index < prev_val || !is_valid) {
jump_power *= 2;
@ -493,33 +491,70 @@ std::vector<std::tuple<sf::Vector3i, char>> Octree::CastRayOctree(
// Clear and pop the idx stack
traversal_state.idx_stack[traversal_state.scale] = 0;
// Scale is now set to the oct above. Be wary of this
traversal_state.scale--;
// Update the prev_val for our new idx
prev_val = traversal_state.idx_stack[traversal_state.scale];
// Clear and pop the parent stack, maybe off by one error?
traversal_state.parent_stack_index[traversal_state.parent_stack_position] = 0;
traversal_state.parent_stack[traversal_state.parent_stack_position] = 0;
traversal_state.parent_stack_position--;
// Compute the new (0,0,0) origin'd oct position
traversal_state.oct_pos.x = floor(traversal_state.oct_pos.x / pow(2, jump_power)) * pow(2, jump_power);
traversal_state.oct_pos.y = floor(traversal_state.oct_pos.y / pow(2, jump_power)) * pow(2, jump_power);
traversal_state.oct_pos.z = floor(traversal_state.oct_pos.z / pow(2, jump_power)) * pow(2, jump_power);
// Set the current CD to the one on top of the stack
traversal_state.current_descriptor =
traversal_state.parent_stack[traversal_state.parent_stack_position];
// Apply the face mask to the new idx for the while check
traversal_state.idx_stack[traversal_state.scale] ^= this_face_mask;
// Get the mask index of the new idx and check the valid status
mask_index = traversal_state.idx_stack[traversal_state.scale];
is_valid = (traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & mask_8[mask_index];
}
// At this point we are at the CP of an oct with a valid oct at the leaf indicated by the current idx in the idx stack
// At this point parent_stack[position] is at the CD of an oct with a valid oct at the leaf indicated by the current
// idx in the idx stack scale
// While we haven't bottomed out and the oct we're looking at is valid
while (jump_power > 1 && is_valid) {
// If all went well and we found a valid non-leaf oct then we will traverse further down the hierarchy
traversal_state.scale++;
jump_power /= 2;
// Count the number of valid octs that come before and add it to the index to get the position
// Negate it by one as it counts itself
int count = count_bits((uint8_t)(traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & count_mask_8[mask_index]) - 1;
// If this CD had the far bit set
if (far_bit_mask & descriptor_buffer[traversal_state.parent_stack_index[traversal_state.parent_stack_position]]) {
// access the far point at which the head points too. Determine it's value, and add
// the count of the valid bits in the current CD to the index
uint64_t far_pointer_index =
traversal_state.parent_stack_index[traversal_state.parent_stack_position] + // current index +
(traversal_state.parent_stack[traversal_state.parent_stack_position] & child_pointer_mask); // the relative prt to the far ptr
while (jump_power > 1) {
// Get the absolute ptr from the far ptr and add the count to get the CD that we want
traversal_state.parent_stack_index[traversal_state.parent_stack_position + 1] = descriptor_buffer[far_pointer_index] + count;
}
// If this CD doesn't have the far bit set, access the element at which head points to
// and then add the specified number of indices to get to the correct child descriptor
else {
traversal_state.parent_stack_index[traversal_state.parent_stack_position + 1] =
traversal_state.parent_stack_index[traversal_state.parent_stack_position] + // The current index to this CD
(traversal_state.parent_stack[traversal_state.parent_stack_position] & child_pointer_mask) + count; // The relative dist + the number of bits that were valid
}
// Now that we have the index set we can increase our parent stack position to the next level and
// retrieve the value of its CD
traversal_state.parent_stack_position++;
traversal_state.parent_stack[traversal_state.parent_stack_position] = descriptor_buffer[traversal_state.parent_stack_index[traversal_state.parent_stack_position]];
// Unlike the single shot DFS, it makes a bit more sense to have this at the tail of the while loop
// Do the logic steps to find which sub oct we step down into
if (voxel.x >= (jump_power / 2) + traversal_state.oct_pos.x) {
@ -532,97 +567,24 @@ std::vector<std::tuple<sf::Vector3i, char>> Octree::CastRayOctree(
}
if (voxel.y >= (jump_power / 2) + traversal_state.oct_pos.y) {
// TODO What the hell is going on with the or operator on this one!??!?!?!
traversal_state.oct_pos.y += (jump_power / 2);
// TODO What is up with the XOR operator that was on this one?
traversal_state.idx_stack[traversal_state.scale] |= idx_set_y_mask;
}
if (voxel.z >= (jump_power / 2) + traversal_state.oct_pos.z) {
traversal_state.oct_pos.z += (jump_power / 2);
traversal_state.idx_stack[traversal_state.scale] |= idx_set_z_mask;
}
// Our count mask matches the way we index our idx so we can just
// copy it over
int mask_index = traversal_state.idx_stack[traversal_state.scale];
// Check to see if we are on a valid oct
if ((traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & mask_8[mask_index]) {
// Check to see if it is a leaf
if ((traversal_state.parent_stack[traversal_state.parent_stack_position] >> 24) & mask_8[mask_index]) {
// If it is, then we cannot traverse further as CP's won't have been generated
traversal_state.found = 1;
return;
}
// If all went well and we found a valid non-leaf oct then we will traverse further down the hierarchy
traversal_state.scale++;
jump_power /= 2;
// Count the number of valid octs that come before and add it to the index to get the position
// Negate it by one as it counts itself
int count = count_bits((uint8_t)(traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & count_mask_8[mask_index]) - 1;
// access the far point at which the head points too. Determine it's value, and add
// a count of the valid bits to the index
if (far_bit_mask & descriptor_buffer[current_index]) {
int far_pointer_index = current_index + (traversal_state.parent_stack[traversal_state.parent_stack_position] & child_pointer_mask);
current_index = descriptor_buffer[far_pointer_index] + count;
}
// access the element at which head points to and then add the specified number of indices
// to get to the correct child descriptor
else {
current_index = current_index + (traversal_state.parent_stack[traversal_state.parent_stack_position] & child_pointer_mask) + count;
}
traversal_state.parent_stack[traversal_state.parent_stack_position] = descriptor_buffer[current_index];
// Increment the parent stack position and put the new oct node as the parent
traversal_state.parent_stack_position++;
traversal_state.parent_stack[traversal_state.parent_stack_position] = traversal_state.parent_stack[traversal_state.parent_stack_position];
}
else {
// If the oct was not valid, then no CP's exists any further
// This implicitly says that if it's non-valid then it must be a leaf!!
// It appears that the traversal is now working but I need
// to focus on how to now take care of the end condition.
// Currently it adds the last parent on the second to lowest
// oct CP. Not sure if thats correct
traversal_state.found = 0;
return;
}
}
// Check to see if we are on a valid oct
if ((traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & Octree::mask_8[mask_index]) {
// Update the mask index with the new voxel we walked down to, and then check it's valid status
mask_index = traversal_state.idx_stack[traversal_state.scale];
is_valid = (traversal_state.parent_stack[traversal_state.parent_stack_position] >> 16) & mask_8[mask_index];
}
// Check to see if we are on top of a valid branch
// Traverse down to the lowest valid oct that the ray is within
// When we pass a split, then that means that we traversed SCALE number of voxels in that direction
// while the bit is valid and we are not bottomed out
// get the cp of the valid branch
//
//
//
//
// At this point we are the furthest down the oct we can get to the voxel.xyz position. This can either
// be at the min oct level with 1:1 traversal, or as high as the max oct. Our jump power has been updated accordingly,
// but we need to update our intersection T's

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