Revert emit_pentagon to work on 3d vectors

manimlib/shaders/quadratic_bezier_fill/geom.glsl

@@ -67,28 +67,25 @@ void emit_simple_triangle(){
 }
 
 
-void emit_pentagon(vec3[3] points){
+void emit_pentagon(vec3[3] points, vec3 normal){
-    vec2 p0 = points[0].xy;
+    vec3 p0 = points[0];
-    vec2 p1 = points[1].xy;
+    vec3 p1 = points[1];
-    vec2 p2 = points[2].xy;
+    vec3 p2 = points[2];
 
     // Tangent vectors
-    vec2 t01 = normalize(p1 - p0);
+    vec3 t01 = normalize(p1 - p0);
-    vec2 t12 = normalize(p2 - p1);
+    vec3 t12 = normalize(p2 - p1);
 
-    // Vectors perpendicular to the curve in the plane
+    // Vectors perpendicular to the curve in the plane of the curve pointing outside the curve
-    // of the curve pointing outside the curve
+    vec3 p0_perp = cross(t01, normal);
-    float cross_prod = cross2d(t01, t12);
+    vec3 p2_perp = cross(t12, normal);
-    float sgn = cross_prod >= 0.0 ? 1.0 : -1.0;
-    vec2 p0_perp = sgn * vec2(t01.y, -t01.x);
-    vec2 p2_perp = sgn * vec2(t12.y, -t12.x);
 
-    float angle = asin(clamp(cross_prod, -1, 1));
+    float angle = acos(clamp(dot(t01, t12), -1, 1));
-    is_linear = float(abs(angle) < ANGLE_THRESHOLD);
+    is_linear = float(angle < ANGLE_THRESHOLD);
 
     bool fill_inside = orientation > 0.0;
     float aaw = anti_alias_width * frame_shape.y / pixel_shape.y;
-    vec2 corners[5] = vec2[5](p0, p0, p1, p2, p2);
+    vec3 corners[5] = vec3[5](p0, p0, p1, p2, p2);
 
     if(fill_inside || bool(is_linear)){
         // Add buffer outside the curve
@@ -103,13 +100,13 @@ void emit_pentagon(vec3[3] points){
     }
 
     // Compute xy_to_uv matrix, and potentially re-evaluate bezier degree
-    mat3 xy_to_uv = get_xy_to_uv(vec2[3](p0, p1, p2), is_linear, is_linear);
+    mat3 xy_to_uv = get_xy_to_uv(vec2[3](p0.xy, p1.xy, p2.xy), is_linear, is_linear);
     uv_anti_alias_width = aaw * length(xy_to_uv[0].xy);
 
     for(int i = 0; i < 5; i++){
         int j = int(sign(i - 1) + 1);  // Maps i = [0, 1, 2, 3, 4] onto j = [0, 0, 1, 2, 2]
-        vec3 corner = vec3(corners[i], points[j].z);
+        vec3 corner = corners[i];
-        uv_coords = (xy_to_uv * vec3(corners[i], 1.0)).xy;
+        uv_coords = (xy_to_uv * vec3(corner.xy, 1.0)).xy;
         emit_vertex_wrapper(corner, j);
     }
     EndPrimitive();
@@ -132,6 +129,6 @@ void main(){
     unit_normal = get_unit_normal(verts);
     orientation = v_orientation[0];
 
-    emit_pentagon(verts);
+    emit_pentagon(verts, unit_normal);
 }