Track unit normal for fill

manimlib/mobject/types/vectorized_mobject.py

@@ -62,8 +62,9 @@ class VMobject(Mobject):
         ('joint_product', np.float32, (4,)),
         ('fill_rgba', np.float32, (4,)),
         ('base_point', np.float32, (3,)),
+        ('unit_normal', np.float32, (3,)),
     ])
-    fill_data_names = ['point', 'fill_rgba', 'base_point']
+    fill_data_names = ['point', 'fill_rgba', 'base_point', 'unit_normal']
     stroke_data_names = ['point', 'stroke_rgba', 'stroke_width', 'joint_product']
 
     fill_render_primitive: int = moderngl.TRIANGLE_STRIP
@@ -827,8 +828,25 @@ class VMobject(Mobject):
                 points[1] - points[0],
                 points[2] - points[1],
             )
+        self.data["unit_normal"][:] = normal
         return normal
 
+    def refresh_unit_normal(self):
+        self.get_unit_normal()
+        return self
+
+    def rotate(
+        self,
+        angle: float,
+        axis: Vect3 = OUT,
+        about_point: Vect3 | None = None,
+        **kwargs
+    ):
+        super().rotate(angle, axis, about_point, **kwargs)
+        for mob in self.get_family():
+            mob.refresh_unit_normal()
+        return self
+
     def ensure_positive_orientation(self, recurse=True):
         for mob in self.get_family(recurse):
             if mob.get_unit_normal()[2] < 0:
@@ -1148,6 +1166,7 @@ class VMobject(Mobject):
         self.refresh_triangulation()
         if refresh_joints:
             self.get_joint_products(refresh=True)
+            self.get_unit_normal()
         return self
 
     @triggers_refreshed_triangulation
@@ -1157,16 +1176,14 @@ class VMobject(Mobject):
         return self
 
     @triggers_refreshed_triangulation
-    def reverse_points(self):
+    def reverse_points(self, recurse: bool = True):
         # This will reset which anchors are
         # considered path ends
-        for mob in self.get_family():
+        for mob in self.get_family(recurse):
             if not mob.has_points():
                 continue
             inner_ends = mob.get_subpath_end_indices()[:-1]
             mob.data["point"][inner_ends + 1] = mob.data["point"][inner_ends + 2]
-        super().reverse_points()
-        return self
 
     @triggers_refreshed_triangulation
     def set_data(self, data: np.ndarray):
@@ -1248,11 +1265,12 @@ class VMobject(Mobject):
         back_stroke_data = []
         for submob in family:
             if submob.has_fill():
-                submob.data["base_point"][:] = submob.data["point"][0]
-                fill_datas.append(submob.data[fill_names])
+                data = submob.data[fill_names]
+                data["base_point"][:] = data["point"][0]
+                fill_datas.append(data)
                 if self._use_winding_fill:
                     # Add dummy
-                    fill_datas.append(submob.data[fill_names][-1:])
+                    fill_datas.append(data[-1:])
                 else:
                     fill_indices.append(submob.get_triangulation())
             if submob.has_stroke():

manimlib/shaders/quadratic_bezier_fill/frag.glsl

@@ -7,6 +7,7 @@ in float fill_all;
 in float orientation;
 in vec2 uv_coords;
 in vec3 point;
+in vec3 unit_normal;
 
 out vec4 frag_color;
 
@@ -14,7 +15,7 @@ out vec4 frag_color;
 
 void main() {
     if (color.a == 0) discard;
-    frag_color = finalize_color(color, point, vec3(0.0, 0.0, 1.0));
+    frag_color = finalize_color(color, point, unit_normal);
     /*
     We want negatively oriented triangles to be canceled with positively
     oriented ones. The easiest way to do this is to give them negative alpha,

manimlib/shaders/quadratic_bezier_fill/geom.glsl

@@ -9,11 +9,13 @@ in vec3 verts[3];
 in vec4 v_color[3];
 in vec3 v_base_point[3];
 in float v_vert_index[3];
+in vec3 v_unit_normal[3];
 
 out vec4 color;
 out float fill_all;
 out float orientation;
 out vec3 point;
+out vec3 unit_normal;
 // uv space is where the curve coincides with y = x^2
 out vec2 uv_coords;
 
@@ -26,12 +28,18 @@ const vec2 SIMPLE_QUADRATIC[3] = vec2[3](
 
 // Analog of import for manim only
 #INSERT get_gl_Position.glsl
-#INSERT get_unit_normal.glsl
 
 
 void emit_triangle(vec3 points[3], vec4 v_color[3]){
-    vec3 unit_normal = get_unit_normal(points[0], points[1], points[2]);
-    orientation = winding ? sign(unit_normal.z) : 1.0;
+    unit_normal = v_unit_normal[1];
+    orientation = 1.0;
+    if(winding){
+        orientation = sign(determinant(mat3(
+            v_unit_normal[1],
+            points[1] - points[0],
+            points[2] - points[0]
+        )));
+    }
 
     for(int i = 0; i < 3; i++){
         uv_coords = SIMPLE_QUADRATIC[i];

manimlib/shaders/quadratic_bezier_fill/vert.glsl

@@ -3,15 +3,18 @@
 in vec3 point;
 in vec4 fill_rgba;
 in vec3 base_point;
+in vec3 unit_normal;
 
 out vec3 verts;  // Bezier control point
 out vec4 v_color;
 out vec3 v_base_point;
+out vec3 v_unit_normal;
 out float v_vert_index;
 
 void main(){
     verts = point;
     v_color = fill_rgba;
     v_base_point = base_point;
+    v_unit_normal = unit_normal;
     v_vert_index = gl_VertexID;
 }