float DensityField::sampleDensity(const vec3& pos) const { // Compute normalized position [0..1]^3 const vec3 n_pos{m_bbox.computeNormPos(pos)}; // Compute texel coordinate vec3 tex_coord{n_pos * vec3{m_res}}; // Use voxel centers as texel values, just as OpenGL does tex_coord -= vec3{0.5f}; // Compute pixel coordinates const int x[2] = {static_cast<int>(floor(tex_coord.x)), static_cast<int>(ceil(tex_coord.x))}; const int y[2] = {static_cast<int>(floor(tex_coord.y)), static_cast<int>(ceil(tex_coord.y))}; const int z[2] = {static_cast<int>(floor(tex_coord.z)), static_cast<int>(ceil(tex_coord.z))}; // Obtain neighbouring samples const float tx{tex_coord.x - x[0]}; const float ty{tex_coord.y - y[0]}; const float tz{tex_coord.z - z[0]}; const float d000{sample(x[0], y[0], z[0])}; const float d100{sample(x[1], y[0], z[0])}; const float d010{sample(x[0], y[1], z[0])}; const float d110{sample(x[1], y[1], z[0])}; const float d001{sample(x[0], y[0], z[1])}; const float d101{sample(x[1], y[0], z[1])}; const float d011{sample(x[0], y[1], z[1])}; const float d111{sample(x[1], y[1], z[1])}; // Perform trilinear interpolation return lerp3D(d000, d100, d010, d110, d001, d101, d011, d111, tx, ty, tz); }