From 394d87effb99bea1d935a82b730ca2ba3edf9a4b Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Fri, 13 Jan 2023 17:26:59 -0800
Subject: [PATCH] Small style tweaks to quadratic_bezier_fill/geom

---
 manimlib/shaders/inserts/get_unit_normal.glsl | 34 +++++++++----------
 .../shaders/quadratic_bezier_fill/geom.glsl   | 18 +++++-----
 .../shaders/quadratic_bezier_fill/vert.glsl   |  4 +--
 3 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/manimlib/shaders/inserts/get_unit_normal.glsl b/manimlib/shaders/inserts/get_unit_normal.glsl
index f5d43382..879871d8 100644
--- a/manimlib/shaders/inserts/get_unit_normal.glsl
+++ b/manimlib/shaders/inserts/get_unit_normal.glsl
@@ -1,22 +1,20 @@
-vec3 get_unit_normal(in vec3[3] points){
+vec3 get_unit_normal(vec3 p0, vec3 p1, vec3 p2){
     float tol = 1e-6;
-    vec3 v1 = normalize(points[1] - points[0]);
-    vec3 v2 = normalize(points[2] - points[1]);
+    vec3 v1 = normalize(p1 - p0);
+    vec3 v2 = normalize(p2 - p1);
     vec3 cp = cross(v1, v2);
     float cp_norm = length(cp);
-    if(cp_norm < tol){
-        // Three points form a line, so find a normal vector
-        // to that line in the plane shared with the z-axis
-        vec3 k_hat = vec3(0.0, 0.0, 1.0);
-        vec3 comb = v1 + v2;
-        vec3 new_cp = cross(cross(comb, k_hat), comb);
-        float new_cp_norm = length(new_cp);
-        if(new_cp_norm < tol){
-            // We only come here if all three points line up
-            // on the z-axis.
-            return vec3(0.0, -1.0, 0.0);
-        }
-        return new_cp / new_cp_norm;
-    }
-    return cp / cp_norm;
+
+    if(cp_norm > tol) return cp / cp_norm;
+
+    // Otherwise, three pionts form a line, so find
+    // a normal vector to that line in the plane shared
+    // with the z-axis
+    vec3 comb = v1 + v2;
+    cp = cross(cross(comb, vec3(0.0, 0.0, 1.0)), comb);
+    cp_norm = length(cp);
+    if(cp_norm > tol) return cp / cp_norm;
+
+    // Otherwise, the points line up with the z-axis.
+    return vec3(0.0, -1.0, 0.0);
 }
\ No newline at end of file
diff --git a/manimlib/shaders/quadratic_bezier_fill/geom.glsl b/manimlib/shaders/quadratic_bezier_fill/geom.glsl
index 7f53a8a7..7b0918d4 100644
--- a/manimlib/shaders/quadratic_bezier_fill/geom.glsl
+++ b/manimlib/shaders/quadratic_bezier_fill/geom.glsl
@@ -17,7 +17,7 @@ uniform float reflectiveness;
 uniform float gloss;
 uniform float shadow;
 
-in vec3 bp[3];
+in vec3 verts[3];
 in float v_orientation[3];
 in vec4 v_color[3];
 in float v_vert_index[3];
@@ -61,17 +61,13 @@ void emit_vertex_wrapper(vec3 point, int index){
 
 void emit_simple_triangle(){
     for(int i = 0; i < 3; i++){
-        emit_vertex_wrapper(bp[i], i);
+        emit_vertex_wrapper(verts[i], i);
     }
     EndPrimitive();
 }
 
 
-void emit_pentagon(vec3[3] points, vec3 normal){
-    vec3 p0 = points[0];
-    vec3 p1 = points[1];
-    vec3 p2 = points[2];
-
+void emit_pentagon(vec3 p0, vec3 p1, vec3 p2, vec3 normal){
     // Tangent vectors
     vec3 t01 = normalize(p1 - p0);
     vec3 t12 = normalize(p2 - p1);
@@ -125,10 +121,12 @@ void main(){
         return;
     }
 
-    vec3[3] verts = vec3[3](bp[0], bp[1], bp[2]);
-    unit_normal = get_unit_normal(verts);
+    vec3 p0 = verts[0];
+    vec3 p1 = verts[1];
+    vec3 p2 = verts[2];
+    unit_normal = get_unit_normal(p0, p1, p2);
     orientation = v_orientation[1];
 
-    emit_pentagon(verts, unit_normal);
+    emit_pentagon(p0, p1, p2, unit_normal);
 }
 
diff --git a/manimlib/shaders/quadratic_bezier_fill/vert.glsl b/manimlib/shaders/quadratic_bezier_fill/vert.glsl
index 2a0fc1a2..2c0ca1c3 100644
--- a/manimlib/shaders/quadratic_bezier_fill/vert.glsl
+++ b/manimlib/shaders/quadratic_bezier_fill/vert.glsl
@@ -7,7 +7,7 @@ in float orientation;
 in vec4 color;
 in float vert_index;
 
-out vec3 bp;  // Bezier control point
+out vec3 verts;  // Bezier control point
 out float v_orientation;
 out vec4 v_color;
 out float v_vert_index;
@@ -16,7 +16,7 @@ out float v_vert_index;
 #INSERT position_point_into_frame.glsl
 
 void main(){
-    bp = position_point_into_frame(point);
+    verts = position_point_into_frame(point);
     v_orientation = orientation;
     v_color = color;
     v_vert_index = vert_index;