/**
 * @File:   grid_encoder_ext_cuda.cpp
 * @Author: Jiaxiang Tang (@ashawkey)
 * @Date:   2023-04-15 10:39:17
 * @Last Modified by: Haozhe Xie
 * @Last Modified at: 2023-04-15 11:01:32
 * @Email:  ashawkey1999@gmail.com
 * @Ref: https://github.com/ashawkey/torch-ngp
 */

#include <stdint.h>
#include <torch/extension.h>
#include <torch/torch.h>

// inputs: [B, D], float, in [0, 1]
// embeddings: [sO, C], float
// offsets: [L + 1], uint32_t
// outputs: [B, L * C], float
// H: base resolution
void grid_encode_forward(const at::Tensor inputs, const at::Tensor embeddings,
                         const at::Tensor offsets, at::Tensor outputs,
                         const uint32_t B, const uint32_t D, const uint32_t C,
                         const uint32_t L, const float S, const uint32_t H,
                         const bool calc_grad_inputs, at::Tensor dy_dx,
                         const uint32_t gridtype, const bool align_corners);
void grid_encode_backward(const at::Tensor grad, const at::Tensor inputs,
                          const at::Tensor embeddings, const at::Tensor offsets,
                          at::Tensor grad_embeddings, const uint32_t B,
                          const uint32_t D, const uint32_t C, const uint32_t L,
                          const float S, const uint32_t H,
                          const bool calc_grad_inputs, const at::Tensor dy_dx,
                          at::Tensor grad_inputs, const uint32_t gridtype,
                          const bool align_corners);

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
  m.def("forward", &grid_encode_forward,
        "grid_encode_forward (CUDA)");
  m.def("backward", &grid_encode_backward,
        "grid_encode_backward (CUDA)");
}