Add is_fixed_in_frame uniform which allows mobjects to not get rotated by the camera

manimlib/camera/camera.py

@@ -148,7 +148,7 @@ class Camera(object):
         "light_source_position": [-10, 10, 10],
         "apply_depth_test": False,
         # Measured in pixel widths, used for vector graphics
-        "anti_alias_width": 1.5,
+        "anti_alias_width": 3,
         # Although vector graphics handle antialiasing fine
         # without multisampling, for 3d scenes one might want
         # to set samples to be greater than 0.
@@ -362,14 +362,11 @@ class Camera(object):
                 for name, path in info["texture_paths"].items():
                     tid = self.get_texture_id(path)
                     shader[name].value = tid
-            for name, value in info["uniforms"].items():
-                shader[name].value = value
-
-            self.set_shader_uniforms(shader)
+            self.set_shader_uniforms(shader, sid)
             self.id_to_shader[sid] = shader
         return self.id_to_shader[sid]
 
-    def set_shader_uniforms(self, shader):
+    def set_shader_uniforms(self, shader, sid):
         if shader is None:
             return
 
@@ -378,13 +375,15 @@ class Camera(object):
         transform = self.frame.get_inverse_camera_position_matrix()
         light = self.light_source.get_location()
         transformed_light = np.dot(transform, [*light, 1])[:3]
-        mapping = {
-            'to_screen_space': tuple(transform.T.flatten()),
-            'frame_shape': self.frame.get_shape(),
-            'focal_distance': self.frame.get_focal_distance(),
-            'anti_alias_width': anti_alias_width,
-            'light_source_position': tuple(transformed_light),
-        }
+        mapping = dict()
+        mapping['to_screen_space'] = tuple(transform.T.flatten())
+        mapping['frame_shape'] = self.frame.get_shape()
+        mapping['focal_distance'] = self.frame.get_focal_distance()
+        mapping['anti_alias_width'] = anti_alias_width
+        mapping['light_source_position'] = tuple(transformed_light)
+        # Potentially overwrite with whatever came from the mobject
+        mapping.update(shader_id_to_info(sid)["uniforms"])
+
         for key, value in mapping.items():
             try:
                 shader[key].value = value
@@ -393,7 +392,7 @@ class Camera(object):
 
     def refresh_shader_uniforms(self):
         for sid, shader in self.id_to_shader.items():
-            self.set_shader_uniforms(shader)
+            self.set_shader_uniforms(shader, sid)
 
     def init_textures(self):
         self.path_to_texture_id = {}

manimlib/mobject/mobject.py

@@ -51,6 +51,8 @@ class Mobject(Container):
         "frag_shader_file": "",
         "render_primative": moderngl.TRIANGLE_STRIP,
         "texture_paths": None,
+        # If true, the mobject will not get rotated according to camera position
+        "is_fixed_in_frame": False,
         # Must match in attributes of vert shader
         "shader_dtype": [
             ('point', np.float32, (3,)),
@@ -455,8 +457,19 @@ class Mobject(Container):
         # Redundant with default behavior of scale now.
         return self.scale(scale_factor, about_point=point)
 
-    def pose_at_angle(self, angle=TAU / 14, axis=UR, **kwargs):
-        return self.rotate(angle, axis, **kwargs)
+    def fix_in_frame(self, family=True):
+        self.is_fixed_in_frame = True
+        if family:
+            for submob in self.submobjects:
+                submob.fix_in_frame(family)
+        return self
+
+    def unfix_from_frame(self, family=True):
+        self.is_fixed_in_frame = False
+        if family:
+            for submob in self.submobjects:
+                submob.unfix_from_frame(family)
+        return self
 
     # Positioning methods
 
@@ -1221,7 +1234,9 @@ class Mobject(Container):
         )
 
     def get_shader_uniforms(self):
-        return {}
+        return {
+            "is_fixed_in_frame": float(self.is_fixed_in_frame),
+        }
 
     def get_shader_data(self):
         # Typically to be implemented by subclasses

manimlib/mobject/types/surface.py

@@ -214,7 +214,9 @@ class TexturedSurface(ParametricSurface):
         return self
 
     def get_shader_uniforms(self):
-        return {"num_textures": self.num_textures}
+        result = super().get_shader_uniforms()
+        result["num_textures"] = self.num_textures
+        return result
 
     def fill_in_shader_color_info(self, data):
         data["im_coords"] = self.get_triangle_ready_array(self.im_coords)

manimlib/mobject/types/vectorized_mobject.py

@@ -830,7 +830,7 @@ class VMobject(Mobject):
             render_primative=self.render_primative,
         )
         fill_info = get_shader_info(
-            uniforms={},
+            uniforms=self.get_shader_uniforms(),
             vert_file=self.fill_vert_shader_file,
             geom_file=self.fill_geom_shader_file,
             frag_file=self.fill_frag_shader_file,
@@ -870,13 +870,15 @@ class VMobject(Mobject):
         return result
 
     def get_stroke_uniforms(self):
-        joint_type_to_code = {
+        j_map = {
             "auto": 0,
             "round": 1,
             "bevel": 2,
             "miter": 3,
         }
-        return {"joint_type": joint_type_to_code[self.joint_type]}
+        result = super().get_shader_uniforms()
+        result["join_type"] = j_map[self.joint_type]
+        return result
 
     def get_stroke_shader_data(self):
         rgbas = self.get_stroke_rgbas()

manimlib/shaders/get_gl_Position.glsl

@@ -1,15 +1,24 @@
 // Assumes the following uniforms exist in the surrounding context:
 // uniform vec2 frame_shape;
 // uniform float focal_distance;
+// uniform float is_fixed_in_frame;
+
+const vec2 DEFAULT_FRAME_SHAPE = vec2(8 * 16 / 9, 8);
 
 vec4 get_gl_Position(vec3 point){
-    point.x *= 2 / frame_shape.x;
-    point.y *= 2 / frame_shape.y;
-    point.z /= focal_distance;
-    point.xy /= max(1 - point.z, 0);
-    // Todo, does this discontinuity add weirdness?  Theoretically, by this point,
-    // the z-coordiante of gl_Position only matter for z-indexing.  The reason
-    // for thie line is to avoid agressive clipping of distant points.
-    if(point.z < 0) point.z *= 0.1;
+    if(!bool(is_fixed_in_frame)){
+        point.x *= 2 / frame_shape.x;
+        point.y *= 2 / frame_shape.y;
+        point.z /= focal_distance;
+        point.xy /= max(1 - point.z, 0);
+        // Todo, does this discontinuity add weirdness?  Theoretically, by this point,
+        // the z-coordiante of gl_Position only matter for z-indexing.  The reason
+        // for thie line is to avoid agressive clipping of distant points.
+        if(point.z < 0) point.z *= 0.1;
+    } else{
+        point.x *= 2 / DEFAULT_FRAME_SHAPE.x;
+        point.y *= 2 / DEFAULT_FRAME_SHAPE.y;
+
+    }
     return vec4(point.xy, -point.z, 1);
 }

manimlib/shaders/image_vert.glsl

@@ -3,6 +3,7 @@
 uniform vec2 frame_shape;
 uniform float anti_alias_width;
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 uniform float focal_distance;
 
 uniform sampler2D Texture;

manimlib/shaders/position_point_into_frame.glsl

@@ -1,7 +1,12 @@
 // Must be used in an environment with the following uniforms:
 // uniform mat4 to_screen_space;
+// uniform float is_fixed_in_frame;
 
 vec3 position_point_into_frame(vec3 point){
-    // Simply apply the pre-computed to_screen_space matrix.
-    return (to_screen_space * vec4(point, 1)).xyz;
+    if(bool(is_fixed_in_frame)){
+        return point;
+    }else{
+        // Simply apply the pre-computed to_screen_space matrix.
+        return (to_screen_space * vec4(point, 1)).xyz;
+    }
 }

manimlib/shaders/quadratic_bezier_fill_frag.glsl

@@ -1,6 +1,7 @@
 #version 330
 
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 
 in vec4 color;
 in float fill_all;  // Either 0 or 1e

manimlib/shaders/quadratic_bezier_fill_geom.glsl

@@ -7,6 +7,7 @@ uniform float anti_alias_width;
 // Needed for get_gl_Position
 uniform vec2 frame_shape;
 uniform float focal_distance;
+uniform float is_fixed_in_frame;
 uniform vec3 light_source_position;
 
 in vec3 bp[3];

manimlib/shaders/quadratic_bezier_fill_vert.glsl

@@ -1,6 +1,7 @@
 #version 330
 
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 
 in vec3 point;
 in vec3 unit_normal;

manimlib/shaders/quadratic_bezier_stroke_frag.glsl

@@ -1,6 +1,7 @@
 #version 330
 
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 uniform vec3 light_source_position;
 
 in vec2 uv_coords;

manimlib/shaders/quadratic_bezier_stroke_geom.glsl

@@ -6,6 +6,7 @@ layout (triangle_strip, max_vertices = 5) out;
 // Needed for get_gl_Position
 uniform vec2 frame_shape;
 uniform float focal_distance;
+uniform float is_fixed_in_frame;
 uniform float anti_alias_width;
 uniform vec3 light_source_position;
 uniform float joint_type;

manimlib/shaders/quadratic_bezier_stroke_vert.glsl

@@ -1,6 +1,7 @@
 #version 330
 
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 uniform float focal_distance;
 
 in vec3 point;

manimlib/shaders/simple_vert.glsl

@@ -3,6 +3,7 @@
 uniform vec2 frame_shape;
 uniform float anti_alias_width;
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 uniform float focal_distance;
 
 in vec3 point;

manimlib/shaders/surface_vert.glsl

@@ -1,8 +1,8 @@
 #version 330
 
 uniform vec2 frame_shape;
-uniform float anti_alias_width;
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 uniform float focal_distance;
 uniform vec3 light_source_position;
 

manimlib/shaders/textured_surface_vert.glsl

@@ -1,8 +1,8 @@
 #version 330
 
 uniform vec2 frame_shape;
-uniform float anti_alias_width;
 uniform mat4 to_screen_space;
+uniform float is_fixed_in_frame;
 uniform float focal_distance;
 uniform vec3 light_source_position;