Gizmo fixes (#7956)

* fix: correct alpha channel usage in fragment color output

* fix: optimize visibility setter to prevent unnecessary updates

* fix: add alpha channel check to discard transparent fragments in unlit shader

* fix: update alpha channel threshold for fragment discard in unlit shader

* fix: add axis flipping functionality in ScaleGizmo based on camera direction

Author: kpal81xd

src/extras/gizmo/scale-gizmo.js

@@ -580,14 +580,16 @@ class ScaleGizmo extends TransformGizmo {
         }
 
         // mirror axes
-        const cameraDir = this.cameraDir;
-        const rot = tmpQ1.copy(this._rootStartRot);
-        let dot = cameraDir.dot(rot.transformVector(Vec3.RIGHT, tmpV1));
-        point.x *= dot < 0 ? -1 : 1;
-        dot = cameraDir.dot(rot.transformVector(Vec3.UP, tmpV1));
-        point.y *= dot < 0 ? -1 : 1;
-        dot = cameraDir.dot(rot.transformVector(Vec3.FORWARD, tmpV1));
-        point.z *= dot > 0 ? -1 : 1;
+        if (this.flipAxes) {
+            const cameraDir = this.cameraDir;
+            const rot = tmpQ1.copy(this._rootStartRot);
+            let dot = cameraDir.dot(rot.transformVector(Vec3.RIGHT, tmpV1));
+            point.x *= dot < 0 ? -1 : 1;
+            dot = cameraDir.dot(rot.transformVector(Vec3.UP, tmpV1));
+            point.y *= dot < 0 ? -1 : 1;
+            dot = cameraDir.dot(rot.transformVector(Vec3.FORWARD, tmpV1));
+            point.z *= dot > 0 ? -1 : 1;
+        }
 
         // uniform scaling for planes
         if (this._uniform && isPlane) {

src/extras/gizmo/shaders.js

@@ -29,7 +29,10 @@ export const unlitShader = {
         uniform vec4 uColor;
 
         void main(void) {
-            gl_FragColor = vec4(gammaCorrectOutput(decodeGamma(uColor)), uColor.w);
+            if (uColor.a < 1.0 / 255.0) {
+                discard;
+            }
+            gl_FragColor = vec4(gammaCorrectOutput(decodeGamma(uColor)), uColor.a);
             #if DEPTH_WRITE == 0
                 gl_FragDepth = 0.0;
             #endif
@@ -58,7 +61,10 @@ export const unlitShader = {
         @fragment
         fn fragmentMain(input: FragmentInput) -> FragmentOutput {
             var output: FragmentOutput;
-            output.color = vec4f(gammaCorrectOutput(decodeGamma(uniform.uColor)), uniform.uColor.w);
+            if (uniform.uColor.a < 1.0 / 255.0) {
+                discard;
+            }
+            output.color = vec4f(gammaCorrectOutput(decodeGamma(uniform.uColor)), uniform.uColor.a);
             #if DEPTH_WRITE == 0
                 output.fragDepth = 0.0;
             #endif

src/extras/gizmo/shape/shape.js

@@ -230,6 +230,9 @@ class Shape {
      * @type {boolean}
      */
     set visible(value) {
+        if (value === this._visible) {
+            return;
+        }
         for (let i = 0; i < this.meshInstances.length; i++) {
             this.meshInstances[i].visible = value;
         }