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https://github.com/Relintai/godot_voxel.git
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85 lines
2.7 KiB
C++
85 lines
2.7 KiB
C++
#ifndef HERMITE_VALUE_H
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#define HERMITE_VALUE_H
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#include "../utility.h"
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#include "../voxel_buffer.h"
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#include <core/math/vector3.h>
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namespace dmc {
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struct HermiteValue {
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// TODO Rename distance, or change usage to be a density
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float value; // Signed "distance" to surface
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Vector3 gradient; // Derivation of the density
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HermiteValue() :
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value(1.0) {
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}
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};
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inline float get_isolevel_clamped(const VoxelBuffer &voxels, unsigned int x, unsigned int y, unsigned int z) {
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x = x >= voxels.get_size().x ? voxels.get_size().x - 1 : x;
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y = y >= voxels.get_size().y ? voxels.get_size().y - 1 : y;
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z = z >= voxels.get_size().z ? voxels.get_size().z - 1 : z;
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return voxels.get_voxel(x, y, z, VoxelBuffer::CHANNEL_ISOLEVEL);
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}
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inline HermiteValue get_hermite_value(const VoxelBuffer &voxels, unsigned int x, unsigned int y, unsigned int z) {
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HermiteValue v;
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v.value = voxels.get_voxel_iso(x, y, z, VoxelBuffer::CHANNEL_ISOLEVEL);
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Vector3 gradient;
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gradient.x = get_isolevel_clamped(voxels, x + 1, y, z) - get_isolevel_clamped(voxels, x - 1, y, z);
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gradient.y = get_isolevel_clamped(voxels, x, y + 1, z) - get_isolevel_clamped(voxels, x, y - 1, z);
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gradient.z = get_isolevel_clamped(voxels, x, y, z + 1) - get_isolevel_clamped(voxels, x, y, z - 1);
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v.gradient = gradient;
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return v;
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}
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inline HermiteValue get_interpolated_hermite_value(const VoxelBuffer &voxels, Vector3 pos) {
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int x0 = static_cast<int>(pos.x);
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int y0 = static_cast<int>(pos.y);
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int z0 = static_cast<int>(pos.z);
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int x1 = static_cast<int>(Math::ceil(pos.x));
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int y1 = static_cast<int>(Math::ceil(pos.y));
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int z1 = static_cast<int>(Math::ceil(pos.z));
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// TODO There are lots of hidden grid accesses here, could be optimized
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//
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// x x x: accessed once, only because of gradient computation
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// x X X x X: accessed for both value and gradient, multiple times for gradient
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// x X X x
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// x x (and this, in 3D)
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HermiteValue v0 = get_hermite_value(voxels, x0, y0, z0);
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HermiteValue v1 = get_hermite_value(voxels, x1, y0, z0);
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HermiteValue v2 = get_hermite_value(voxels, x1, y0, z1);
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HermiteValue v3 = get_hermite_value(voxels, x0, y0, z1);
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HermiteValue v4 = get_hermite_value(voxels, x0, y1, z0);
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HermiteValue v5 = get_hermite_value(voxels, x1, y1, z0);
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HermiteValue v6 = get_hermite_value(voxels, x1, y1, z1);
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HermiteValue v7 = get_hermite_value(voxels, x0, y1, z1);
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Vector3 rpos = pos - Vector3(x0, y0, z0);
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HermiteValue v;
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v.value = ::interpolate(v0.value, v1.value, v2.value, v3.value, v4.value, v5.value, v6.value, v7.value, rpos);
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v.gradient = ::interpolate(v0.gradient, v1.gradient, v2.gradient, v3.gradient, v4.gradient, v5.gradient, v6.gradient, v7.gradient, rpos);
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return v;
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}
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} // namespace dmc
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#endif // HERMITE_VALUE_H
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