Index out of array boundary of a corner case

[__trrbivial_innocence]

I am running demo_render.py with input file of obj/spot/spot_triangulated.obj and default configuration.

I find in this code

template <typename scalar_t>
__device__ __forceinline__ void barycentric_clip(scalar_t *w) {
    for (int k = 0; k < 3; k++) w[k] = max(min(w[k], 1.), 0.);
    const scalar_t w_sum = max(w[0] + w[1] + w[2], 1e-5);
    for (int k = 0; k < 3; k++) w[k] /= w_sum;
}

When the input w is [-0.25856018 , 1.4101562, -0.15160179]

It will become [0.0, 1.0, 0.0] after this function

However, when sampling texture

template <typename scalar_t>
__device__ __forceinline__ scalar_t forward_sample_texture(const scalar_t *texture, const scalar_t *w, const int R, const int k, const int texture_sample_type) {
    scalar_t texture_k = 0;
    if (texture_sample_type == 0) { // sample surface color with resolution as R
        const int w_x = w[0] * R;
        const int w_y = w[1] * R;
        if ((w[0] + w[1]) * R - w_x - w_y <= 1) {
            texture_k = texture[(w_y * R + w_x) * 3 + k];
        } else {
            texture_k = texture[((R - 1 - w_y) * R + (R - 1 - w_x)) * 3 + k];
        }
    } else
    if (texture_sample_type == 1) { // sample vertex color
        texture_k = w[0] * texture[k] + w[1] * texture[3+k] + w[2] * texture[6+k];
    }
    return texture_k;
}

In this branch

if ((w[0] + w[1]) * R - w_x - w_y <= 1) {
            texture_k = texture[(w_y * R + w_x) * 3 + k];

Where R == 5, w[0] + w[1] == 1.0, w_x == 0, w_y == 5

It will read the texture by the index of [bn, fn, 25, k]

As far as I know, the shape of texture is defined as [batch_size, num_faces, texture_size, 3] where texture_size == 25

Maybe it is a small bug.