From b7831ef3f1479c16e75a71f7f5ef0dc61f7175d4 Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Tue, 17 Jan 2023 17:27:20 -0800
Subject: [PATCH] Go back to computing xyz-to-uv before repositioning

---
 manimlib/shaders/quadratic_bezier_stroke/geom.glsl | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/manimlib/shaders/quadratic_bezier_stroke/geom.glsl b/manimlib/shaders/quadratic_bezier_stroke/geom.glsl
index b38787df..7673de91 100644
--- a/manimlib/shaders/quadratic_bezier_stroke/geom.glsl
+++ b/manimlib/shaders/quadratic_bezier_stroke/geom.glsl
@@ -179,12 +179,7 @@ void main() {
     // the case of a linear curve (bezier degree 1), just put it on
     // the segment from (0, 0) to (1, 0)
     // mat3 xy_to_uv = get_xy_to_uv(p0.xy, p1.xy, p2.xy, is_linear, is_linear);
-    mat4 xyz_to_uv = get_xyz_to_uv(
-        position_point_into_frame(p0),
-        position_point_into_frame(p1),
-        position_point_into_frame(p2),
-        is_linear, is_linear
-    );
+    mat4 xyz_to_uv = get_xyz_to_uv(p0, p1, p2, is_linear, is_linear);
 
     float uv_scale_factor = length(xyz_to_uv[0].xyz);
     float scaled_aaw = anti_alias_width * (frame_shape.y / pixel_shape.y);
@@ -196,15 +191,14 @@ void main() {
     // Emit each corner
     for(int i = 0; i < 6; i++){
         int vert_index = i / 2;
-        vec3 pos = corners[i];
-        uv_coords = (xyz_to_uv * vec4(pos, 1)).xy;
+        uv_coords = (xyz_to_uv * vec4(corners[i], 1)).xy;
         uv_stroke_width = uv_scale_factor * v_stroke_width[vert_index];
         color = finalize_color(
             v_color[vert_index],
             corners[i],
             vec3(0.0, 0.0, 1.0) // TODO
         );
-        gl_Position = get_gl_Position(pos);
+        gl_Position = get_gl_Position(position_point_into_frame(corners[i]));
         EmitVertex();
     }
     EndPrimitive();