Flat tangent (#8751)

* Flat tangent

* Whats new

* whats new

Co-authored-by: Alejandro Toledo <alex@pixelspace.com>

dist/preview release/what's new.md

@@ -9,7 +9,7 @@
 - Reflection probes can now be used to give accurate shading with PBR ([CraigFeldpsar](https://github.com/craigfeldspar) and ([Sebavan](https://github.com/sebavan/)))
 - Added SubSurfaceScattering on PBR materials ([CraigFeldpsar](https://github.com/craigfeldspar) and ([Sebavan](https://github.com/sebavan/)))
 - Added editing of PBR materials, Post processes and Particle fragment shaders in the node material editor ([Popov72](https://github.com/Popov72))
-- Added Curve editor to manage selected entity's animations and edit animation groups in Inspector ([pixelspace](https://github.com/devpixelspace))
+- Added Curve editor to manage entity's animations and edit animation groups in Inspector ([pixelspace](https://github.com/devpixelspace))
 - Added support in `ShadowGenerator` for fast fake soft transparent shadows ([Popov72](https://github.com/Popov72))
 - Added support for **thin instances** for faster mesh instances. [Doc](https://doc.babylonjs.com/how_to/how_to_use_thininstances) ([Popov72](https://github.com/Popov72))
 

src/Animations/animation.ts

@@ -1029,10 +1029,10 @@ export class Animation {
             switch (dataType) {
                 case Animation.ANIMATIONTYPE_FLOAT:
                     key.values = [animationKey.value];
-                    if (animationKey.inTangent) {
+                    if (animationKey.inTangent !== undefined) {
                         key.values.push(animationKey.inTangent);
                     }
-                    if (animationKey.outTangent) {
+                    if (animationKey.outTangent !== undefined) {
                         if (animationKey.inTangent === undefined) {
                             key.values.push(undefined);
                         }
@@ -1045,10 +1045,10 @@ export class Animation {
                 case Animation.ANIMATIONTYPE_COLOR3:
                 case Animation.ANIMATIONTYPE_COLOR4:
                     key.values = animationKey.value.asArray();
-                    if (animationKey.inTangent) {
+                    if (animationKey.inTangent != undefined) {
                         key.values.push(animationKey.inTangent.asArray());
                     }
-                    if (animationKey.outTangent) {
+                    if (animationKey.outTangent != undefined) {
                         if (animationKey.inTangent === undefined) {
                             key.values.push(undefined);
                         }