Stop tracking unit_normal in data

Track orientation of each curve instead

manimlib/mobject/types/vectorized_mobject.py

@@ -53,7 +53,7 @@ class VMobject(Mobject):
     fill_shader_folder: str = "quadratic_bezier_fill"
     fill_dtype: Sequence[Tuple[str, type, Tuple[int]]] = [
         ('point', np.float32, (3,)),
-        ('unit_normal', np.float32, (3,)),
+        ('orientation', np.float32, (1,)),
         ('color', np.float32, (4,)),
         ('vert_index', np.float32, (1,)),
     ]
@@ -61,7 +61,6 @@ class VMobject(Mobject):
         ("point", np.float32, (3,)),
         ("prev_point", np.float32, (3,)),
         ("next_point", np.float32, (3,)),
-        ('unit_normal', np.float32, (3,)),
         ("stroke_width", np.float32, (1,)),
         ("color", np.float32, (4,)),
     ]
@@ -100,7 +99,6 @@ class VMobject(Mobject):
         self.flat_stroke = flat_stroke
 
         self.needs_new_triangulation = True
-        self.needs_new_unit_normal = True
         self.triangulation = np.zeros(0, dtype='i4')
 
         super().__init__(**kwargs)
@@ -115,7 +113,7 @@ class VMobject(Mobject):
             "fill_rgba": np.zeros((1, 4)),
             "stroke_rgba": np.zeros((1, 4)),
             "stroke_width": np.zeros((1, 1)),
-            "unit_normal": np.array(OUT, ndmin=2),
+            "orientation": np.zeros((1, 1)),
         })
 
     # These are here just to make type checkers happy
@@ -776,10 +774,7 @@ class VMobject(Mobject):
             sum((p0[:, 0] + p1[:, 0]) * (p1[:, 1] - p0[:, 1])),  # Add up (x1 + x2)*(y2 - y1)
         ])
 
-    def get_unit_normal(self, recompute: bool = False) -> Vect3:
-        if not self.needs_new_unit_normal and not recompute:
-            return self.data["unit_normal"][0]
-
+    def get_unit_normal(self) -> Vect3:
         if self.get_num_points() < 3:
             return OUT
 
@@ -793,13 +788,9 @@ class VMobject(Mobject):
                 points[1] - points[0],
                 points[2] - points[1],
             )
-        self.data["unit_normal"][:] = normal
-        self.needs_new_unit_normal = False
         return normal
 
-    def refresh_unit_normal(self):
-        for mob in self.get_family():
-            mob.needs_new_unit_normal = True
+    def refresh_unit_normal(self):  # TODO, Delete
         return self
 
     # Alignment
@@ -958,13 +949,10 @@ class VMobject(Mobject):
             mob.needs_new_triangulation = True
         return self
 
-    def get_triangulation(self, normal_vector: Vect3 | None = None):
+    def get_triangulation(self):
         # Figure out how to triangulate the interior to know
         # how to send the points as to the vertex shader.
         # First triangles come directly from the points
-        if normal_vector is None:
-            normal_vector = self.get_unit_normal(recompute=True)
-
         if not self.needs_new_triangulation:
             return self.triangulation
 
@@ -975,6 +963,7 @@ class VMobject(Mobject):
             self.needs_new_triangulation = False
             return self.triangulation
 
+        normal_vector = self.get_unit_normal()
         if not np.isclose(normal_vector, OUT).all():
             # Rotate points such that unit normal vector is OUT
             points = np.dot(points, z_to_vector(normal_vector))
@@ -988,6 +977,8 @@ class VMobject(Mobject):
 
         crosses = cross2d(v01s, v12s)
         convexities = np.sign(crosses)
+        orientations = np.sign(convexities.repeat(3))
+        self.data["orientation"] = orientations.reshape((len(orientations), 1))
 
         atol = self.tolerance_for_point_equality
         end_of_loop = np.zeros(len(b0s), dtype=bool)
@@ -1155,7 +1146,6 @@ class VMobject(Mobject):
 
         self.read_data_to_shader(self.stroke_data, "color", "stroke_rgba")
         self.read_data_to_shader(self.stroke_data, "stroke_width", "stroke_width")
-        self.read_data_to_shader(self.stroke_data, "unit_normal", "unit_normal")
 
         return self.stroke_data
 
@@ -1167,7 +1157,7 @@ class VMobject(Mobject):
 
         self.read_data_to_shader(self.fill_data, "point", "points")
         self.read_data_to_shader(self.fill_data, "color", "fill_rgba")
-        self.read_data_to_shader(self.fill_data, "unit_normal", "unit_normal")
+        self.read_data_to_shader(self.fill_data, "orientation", "orientation")
 
         return self.fill_data
 

manimlib/shaders/quadratic_bezier_fill/geom.glsl

@@ -17,7 +17,7 @@ uniform float gloss;
 uniform float shadow;
 
 in vec3 bp[3];
-in vec3 v_global_unit_normal[3];
+in float v_orientation[3];
 in vec4 v_color[3];
 in float v_vert_index[3];
 
@@ -32,6 +32,8 @@ out vec2 uv_coords;
 out vec2 uv_b2;
 out float bezier_degree;
 
+vec3 local_unit_normal;
+
 
 // Analog of import for manim only
 #INSERT quadratic_bezier_geometry_functions.glsl
@@ -44,7 +46,7 @@ void emit_vertex_wrapper(vec3 point, int index){
     color = finalize_color(
         v_color[index],
         point,
-        v_global_unit_normal[index],
+        local_unit_normal,
         light_source_position,
         camera_position,
         reflectiveness,
@@ -128,7 +130,7 @@ void main(){
     vec3 new_bp[3];
     bezier_degree = get_reduced_control_points(vec3[3](bp[0], bp[1], bp[2]), new_bp);
     vec3 local_unit_normal = get_unit_normal(new_bp);
-    orientation = sign(dot(v_global_unit_normal[0], local_unit_normal));
+    orientation = v_orientation[0];
 
     if(bezier_degree >= 1){
         emit_pentagon(new_bp, local_unit_normal);

manimlib/shaders/quadratic_bezier_fill/vert.glsl

@@ -3,12 +3,12 @@
 #INSERT camera_uniform_declarations.glsl
 
 in vec3 point;
-in vec3 unit_normal;
+in float orientation;
 in vec4 color;
 in float vert_index;
 
 out vec3 bp;  // Bezier control point
-out vec3 v_global_unit_normal;
+out float v_orientation;
 out vec4 v_color;
 out float v_vert_index;
 
@@ -17,7 +17,7 @@ out float v_vert_index;
 
 void main(){
     bp = position_point_into_frame(point);
-    v_global_unit_normal = rotate_point_into_frame(unit_normal);
+    v_orientation = orientation;
     v_color = color;
     v_vert_index = vert_index;
 }

manimlib/shaders/quadratic_bezier_stroke/geom.glsl

@@ -22,7 +22,6 @@ uniform float shadow;
 in vec3 bp[3];
 in vec3 prev_bp[3];
 in vec3 next_bp[3];
-in vec3 v_global_unit_normal[3];
 
 in vec4 v_color[3];
 in float v_stroke_width[3];
@@ -43,6 +42,8 @@ out float bezier_degree;
 out vec2 uv_coords;
 out vec2 uv_b2;
 
+vec3 unit_normal;
+
 // Codes for joint types
 const float AUTO_JOINT = 0;
 const float ROUND_JOINT = 1;
@@ -206,6 +207,7 @@ void main() {
     vec3 controls[3];
     vec3 prev[3];
     vec3 next[3];
+    unit_normal = get_unit_normal(controls);
     bezier_degree = get_reduced_control_points(vec3[3](bp[0], bp[1], bp[2]), controls);
     if(bezier_degree == 0.0) return;  // Null curve
     int degree = int(bezier_degree);
@@ -219,7 +221,7 @@ void main() {
         float sf = perspective_scale_factor(controls[i].z, focal_distance);
         if(bool(flat_stroke)){
             vec3 to_cam = normalize(vec3(0.0, 0.0, focal_distance) - controls[i]);
-            sf *= abs(dot(v_global_unit_normal[i], to_cam));
+            sf *= abs(dot(unit_normal, to_cam));
         }
         scaled_strokes[i] = v_stroke_width[i] * sf;
     }
@@ -259,7 +261,7 @@ void main() {
         color = finalize_color(
             v_color[index_map[i]],
             xyz_coords,
-            v_global_unit_normal[index_map[i]],
+            unit_normal,
             light_source_position,
             camera_position,
             reflectiveness,

manimlib/shaders/quadratic_bezier_stroke/vert.glsl

@@ -14,7 +14,6 @@ in vec4 color;
 out vec3 bp;
 out vec3 prev_bp;
 out vec3 next_bp;
-out vec3 v_global_unit_normal;
 
 out float v_stroke_width;
 out vec4 v_color;
@@ -27,7 +26,6 @@ void main(){
     bp = position_point_into_frame(point);
     prev_bp = position_point_into_frame(prev_point);
     next_bp = position_point_into_frame(next_point);
-    v_global_unit_normal = rotate_point_into_frame(unit_normal);
 
     v_stroke_width = STROKE_WIDTH_CONVERSION * stroke_width * frame_shape[1] / 8.0;
     v_color = color;