SplatterPhongShader 1: Pull out common Shader functionality into ShaderBase

Summary: Most of the shaders copypaste exactly the same code into `__init__` and `to`. I will be adding a new shader in the next diff, so let's make it a bit easier.

Reviewed By: bottler

Differential Revision: D35767884

fbshipit-source-id: 0057e3e2ae3be4eaa49ae7e2bf3e4176953dde9d

Author: Krzysztof Chalupka

Diff for: pytorch3d/renderer/mesh/shader.py

@@ -32,22 +32,7 @@
 #     - sample colors from a texture map
 #     - apply per pixel lighting
 #     - blend colors across top K faces per pixel.
-
-
-class HardPhongShader(nn.Module):
-    """
-    Per pixel lighting - the lighting model is applied using the interpolated
-    coordinates and normals for each pixel. The blending function hard assigns
-    the color of the closest face for each pixel.
-
-    To use the default values, simply initialize the shader with the desired
-    device e.g.
-
-    .. code-block::
-
-        shader = HardPhongShader(device=torch.device("cuda:0"))
-    """
-
+class ShaderBase(nn.Module):
     def __init__(
         self,
         device: Device = "cpu",
@@ -74,6 +59,21 @@ def to(self, device: Device):
         self.lights = self.lights.to(device)
         return self
 
+
+class HardPhongShader(ShaderBase):
+    """
+    Per pixel lighting - the lighting model is applied using the interpolated
+    coordinates and normals for each pixel. The blending function hard assigns
+    the color of the closest face for each pixel.
+
+    To use the default values, simply initialize the shader with the desired
+    device e.g.
+
+    .. code-block::
+
+        shader = HardPhongShader(device=torch.device("cuda:0"))
+    """
+
     def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tensor:
         cameras = kwargs.get("cameras", self.cameras)
         if cameras is None:
@@ -97,7 +97,7 @@ def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tenso
         return images
 
 
-class SoftPhongShader(nn.Module):
+class SoftPhongShader(ShaderBase):
     """
     Per pixel lighting - the lighting model is applied using the interpolated
     coordinates and normals for each pixel. The blending function returns the
@@ -111,32 +111,6 @@ class SoftPhongShader(nn.Module):
         shader = SoftPhongShader(device=torch.device("cuda:0"))
     """
 
-    def __init__(
-        self,
-        device: Device = "cpu",
-        cameras: Optional[TensorProperties] = None,
-        lights: Optional[TensorProperties] = None,
-        materials: Optional[Materials] = None,
-        blend_params: Optional[BlendParams] = None,
-    ) -> None:
-        super().__init__()
-        self.lights = lights if lights is not None else PointLights(device=device)
-        self.materials = (
-            materials if materials is not None else Materials(device=device)
-        )
-        self.cameras = cameras
-        self.blend_params = blend_params if blend_params is not None else BlendParams()
-
-    # pyre-fixme[14]: `to` overrides method defined in `Module` inconsistently.
-    def to(self, device: Device):
-        # Manually move to device modules which are not subclasses of nn.Module
-        cameras = self.cameras
-        if cameras is not None:
-            self.cameras = cameras.to(device)
-        self.materials = self.materials.to(device)
-        self.lights = self.lights.to(device)
-        return self
-
     def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tensor:
         cameras = kwargs.get("cameras", self.cameras)
         if cameras is None:
@@ -164,7 +138,7 @@ def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tenso
         return images
 
 
-class HardGouraudShader(nn.Module):
+class HardGouraudShader(ShaderBase):
     """
     Per vertex lighting - the lighting model is applied to the vertex colors and
     the colors are then interpolated using the barycentric coordinates to
@@ -179,32 +153,6 @@ class HardGouraudShader(nn.Module):
         shader = HardGouraudShader(device=torch.device("cuda:0"))
     """
 
-    def __init__(
-        self,
-        device: Device = "cpu",
-        cameras: Optional[TensorProperties] = None,
-        lights: Optional[TensorProperties] = None,
-        materials: Optional[Materials] = None,
-        blend_params: Optional[BlendParams] = None,
-    ) -> None:
-        super().__init__()
-        self.lights = lights if lights is not None else PointLights(device=device)
-        self.materials = (
-            materials if materials is not None else Materials(device=device)
-        )
-        self.cameras = cameras
-        self.blend_params = blend_params if blend_params is not None else BlendParams()
-
-    # pyre-fixme[14]: `to` overrides method defined in `Module` inconsistently.
-    def to(self, device: Device):
-        # Manually move to device modules which are not subclasses of nn.Module
-        cameras = self.cameras
-        if cameras is not None:
-            self.cameras = cameras.to(device)
-        self.materials = self.materials.to(device)
-        self.lights = self.lights.to(device)
-        return self
-
     def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tensor:
         cameras = kwargs.get("cameras", self.cameras)
         if cameras is None:
@@ -231,7 +179,7 @@ def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tenso
         return images
 
 
-class SoftGouraudShader(nn.Module):
+class SoftGouraudShader(ShaderBase):
     """
     Per vertex lighting - the lighting model is applied to the vertex colors and
     the colors are then interpolated using the barycentric coordinates to
@@ -246,32 +194,6 @@ class SoftGouraudShader(nn.Module):
         shader = SoftGouraudShader(device=torch.device("cuda:0"))
     """
 
-    def __init__(
-        self,
-        device: Device = "cpu",
-        cameras: Optional[TensorProperties] = None,
-        lights: Optional[TensorProperties] = None,
-        materials: Optional[Materials] = None,
-        blend_params: Optional[BlendParams] = None,
-    ) -> None:
-        super().__init__()
-        self.lights = lights if lights is not None else PointLights(device=device)
-        self.materials = (
-            materials if materials is not None else Materials(device=device)
-        )
-        self.cameras = cameras
-        self.blend_params = blend_params if blend_params is not None else BlendParams()
-
-    # pyre-fixme[14]: `to` overrides method defined in `Module` inconsistently.
-    def to(self, device: Device):
-        # Manually move to device modules which are not subclasses of nn.Module
-        cameras = self.cameras
-        if cameras is not None:
-            self.cameras = cameras.to(device)
-        self.materials = self.materials.to(device)
-        self.lights = self.lights.to(device)
-        return self
-
     def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tensor:
         cameras = kwargs.get("cameras", self.cameras)
         if cameras is None:
@@ -320,7 +242,7 @@ def TexturedSoftPhongShader(
     )
 
 
-class HardFlatShader(nn.Module):
+class HardFlatShader(ShaderBase):
     """
     Per face lighting - the lighting model is applied using the average face
     position and the face normal. The blending function hard assigns
@@ -334,32 +256,6 @@ class HardFlatShader(nn.Module):
         shader = HardFlatShader(device=torch.device("cuda:0"))
     """
 
-    def __init__(
-        self,
-        device: Device = "cpu",
-        cameras: Optional[TensorProperties] = None,
-        lights: Optional[TensorProperties] = None,
-        materials: Optional[Materials] = None,
-        blend_params: Optional[BlendParams] = None,
-    ) -> None:
-        super().__init__()
-        self.lights = lights if lights is not None else PointLights(device=device)
-        self.materials = (
-            materials if materials is not None else Materials(device=device)
-        )
-        self.cameras = cameras
-        self.blend_params = blend_params if blend_params is not None else BlendParams()
-
-    # pyre-fixme[14]: `to` overrides method defined in `Module` inconsistently.
-    def to(self, device: Device):
-        # Manually move to device modules which are not subclasses of nn.Module
-        cameras = self.cameras
-        if cameras is not None:
-            self.cameras = cameras.to(device)
-        self.materials = self.materials.to(device)
-        self.lights = self.lights.to(device)
-        return self
-
     def forward(self, fragments: Fragments, meshes: Meshes, **kwargs) -> torch.Tensor:
         cameras = kwargs.get("cameras", self.cameras)
         if cameras is None: