Add mesh_processor.py from upstream PR by MrForExample

MrForExample https://github.com/Tencent/Hunyuan3D-2/pull/13

hy3dgen/texgen/differentiable_renderer/mesh_processor.py

@@ -0,0 +1,72 @@
+#code by MrForExample https://github.com/Tencent/Hunyuan3D-2/pull/13
+
+import numpy as np
+
+def meshVerticeInpaint_smooth(texture, mask, vtx_pos, vtx_uv, pos_idx, uv_idx):
+    texture_height, texture_width, texture_channel = texture.shape
+    vtx_num = vtx_pos.shape[0]
+
+    vtx_mask = np.zeros(vtx_num, dtype=np.float32)
+    vtx_color = [np.zeros(texture_channel, dtype=np.float32) for _ in range(vtx_num)]
+    uncolored_vtxs = []
+    G = [[] for _ in range(vtx_num)]
+
+    for i in range(uv_idx.shape[0]):
+        for k in range(3):
+            vtx_uv_idx = uv_idx[i, k]
+            vtx_idx = pos_idx[i, k]
+            uv_v = int(round(vtx_uv[vtx_uv_idx, 0] * (texture_width - 1)))
+            uv_u = int(round((1.0 - vtx_uv[vtx_uv_idx, 1]) * (texture_height - 1)))
+            if mask[uv_u, uv_v] > 0:
+                vtx_mask[vtx_idx] = 1.0
+                vtx_color[vtx_idx] = texture[uv_u, uv_v]
+            else:
+                uncolored_vtxs.append(vtx_idx)
+            G[pos_idx[i, k]].append(pos_idx[i, (k + 1) % 3])
+
+    smooth_count = 2
+    last_uncolored_vtx_count = 0
+    while smooth_count > 0:
+        uncolored_vtx_count = 0
+        for vtx_idx in uncolored_vtxs:
+            sum_color = np.zeros(texture_channel, dtype=np.float32)
+            total_weight = 0.0
+            vtx_0 = vtx_pos[vtx_idx]
+            for connected_idx in G[vtx_idx]:
+                if vtx_mask[connected_idx] > 0:
+                    vtx1 = vtx_pos[connected_idx]
+                    dist = np.sqrt(np.sum((vtx_0 - vtx1) ** 2))
+                    dist_weight = 1.0 / max(dist, 1e-4)
+                    dist_weight *= dist_weight
+                    sum_color += vtx_color[connected_idx] * dist_weight
+                    total_weight += dist_weight
+            if total_weight > 0:
+                vtx_color[vtx_idx] = sum_color / total_weight
+                vtx_mask[vtx_idx] = 1.0
+            else:
+                uncolored_vtx_count += 1
+
+        if last_uncolored_vtx_count == uncolored_vtx_count:
+            smooth_count -= 1
+        else:
+            smooth_count += 1
+        last_uncolored_vtx_count = uncolored_vtx_count
+
+    new_texture = texture.copy()
+    new_mask = mask.copy()
+    for face_idx in range(uv_idx.shape[0]):
+        for k in range(3):
+            vtx_uv_idx = uv_idx[face_idx, k]
+            vtx_idx = pos_idx[face_idx, k]
+            if vtx_mask[vtx_idx] == 1.0:
+                uv_v = int(round(vtx_uv[vtx_uv_idx, 0] * (texture_width - 1)))
+                uv_u = int(round((1.0 - vtx_uv[vtx_uv_idx, 1]) * (texture_height - 1)))
+                new_texture[uv_u, uv_v] = vtx_color[vtx_idx]
+                new_mask[uv_u, uv_v] = 255
+    return new_texture, new_mask
+
+def meshVerticeInpaint(texture, mask, vtx_pos, vtx_uv, pos_idx, uv_idx, method="smooth"):
+    if method == "smooth":
+        return meshVerticeInpaint_smooth(texture, mask, vtx_pos, vtx_uv, pos_idx, uv_idx)
+    else:
+        raise ValueError("Invalid method. Use 'smooth' or 'forward'.")