Fix Gen3D folder name

Gen_3D_Modules/InstantMesh/models/decoder/transformer.py

@@ -0,0 +1,123 @@
+# Copyright (c) 2023, Zexin He
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import torch
+import torch.nn as nn
+
+
+class BasicTransformerBlock(nn.Module):
+    """
+    Transformer block that takes in a cross-attention condition and another modulation vector applied to sub-blocks.
+    """
+    # use attention from torch.nn.MultiHeadAttention
+    # Block contains a cross-attention layer, a self-attention layer, and a MLP
+    def __init__(
+        self, 
+        inner_dim: int, 
+        cond_dim: int, 
+        num_heads: int, 
+        eps: float,
+        attn_drop: float = 0., 
+        attn_bias: bool = False,
+        mlp_ratio: float = 4., 
+        mlp_drop: float = 0.,
+    ):
+        super().__init__()
+
+        self.norm1 = nn.LayerNorm(inner_dim)
+        self.cross_attn = nn.MultiheadAttention(
+            embed_dim=inner_dim, num_heads=num_heads, kdim=cond_dim, vdim=cond_dim,
+            dropout=attn_drop, bias=attn_bias, batch_first=True)
+        self.norm2 = nn.LayerNorm(inner_dim)
+        self.self_attn = nn.MultiheadAttention(
+            embed_dim=inner_dim, num_heads=num_heads,
+            dropout=attn_drop, bias=attn_bias, batch_first=True)
+        self.norm3 = nn.LayerNorm(inner_dim)
+        self.mlp = nn.Sequential(
+            nn.Linear(inner_dim, int(inner_dim * mlp_ratio)),
+            nn.GELU(),
+            nn.Dropout(mlp_drop),
+            nn.Linear(int(inner_dim * mlp_ratio), inner_dim),
+            nn.Dropout(mlp_drop),
+        )
+
+    def forward(self, x, cond):
+        # x: [N, L, D]
+        # cond: [N, L_cond, D_cond]
+        x = x + self.cross_attn(self.norm1(x), cond, cond)[0]
+        before_sa = self.norm2(x)
+        x = x + self.self_attn(before_sa, before_sa, before_sa)[0]
+        x = x + self.mlp(self.norm3(x))
+        return x
+
+
+class TriplaneTransformer(nn.Module):
+    """
+    Transformer with condition that generates a triplane representation.
+    
+    Reference:
+    Timm: https://github.com/huggingface/pytorch-image-models/blob/main/timm/models/vision_transformer.py#L486
+    """
+    def __init__(
+        self, 
+        inner_dim: int, 
+        image_feat_dim: int,
+        triplane_low_res: int, 
+        triplane_high_res: int, 
+        triplane_dim: int,
+        num_layers: int, 
+        num_heads: int,
+        eps: float = 1e-6,
+    ):
+        super().__init__()
+
+        # attributes
+        self.triplane_low_res = triplane_low_res
+        self.triplane_high_res = triplane_high_res
+        self.triplane_dim = triplane_dim
+
+        # modules
+        # initialize pos_embed with 1/sqrt(dim) * N(0, 1)
+        self.pos_embed = nn.Parameter(torch.randn(1, 3*triplane_low_res**2, inner_dim) * (1. / inner_dim) ** 0.5)
+        self.layers = nn.ModuleList([
+            BasicTransformerBlock(
+                inner_dim=inner_dim, cond_dim=image_feat_dim, num_heads=num_heads, eps=eps)
+            for _ in range(num_layers)
+        ])
+        self.norm = nn.LayerNorm(inner_dim, eps=eps)
+        self.deconv = nn.ConvTranspose2d(inner_dim, triplane_dim, kernel_size=2, stride=2, padding=0)
+
+    def forward(self, image_feats):
+        # image_feats: [N, L_cond, D_cond]
+
+        N = image_feats.shape[0]
+        H = W = self.triplane_low_res
+        L = 3 * H * W
+
+        x = self.pos_embed.repeat(N, 1, 1)  # [N, L, D]
+        for layer in self.layers:
+            x = layer(x, image_feats)
+        x = self.norm(x)
+
+        # separate each plane and apply deconv
+        x = x.view(N, 3, H, W, -1)
+        x = torch.einsum('nihwd->indhw', x)  # [3, N, D, H, W]
+        x = x.contiguous().view(3*N, -1, H, W)  # [3*N, D, H, W]
+        x = self.deconv(x)  # [3*N, D', H', W']
+        x = x.view(3, N, *x.shape[-3:])  # [3, N, D', H', W']
+        x = torch.einsum('indhw->nidhw', x)  # [N, 3, D', H', W']
+        x = x.contiguous()
+
+        return x