Bug 1768094 - Add even more vecN_scalar friend operators to avoid some implicit conversions. r=gfx-reviewers,bradwerth

There are a few more cases we need to cover of the float OP vecN_scalar variety that are still left.

Differential Revision: https://phabricator.services.mozilla.com/D145932

gfx/wr/swgl/src/glsl.h

@@ -405,6 +405,9 @@ struct vec2_scalar {
   friend vec2_scalar operator-(vec2_scalar a, float b) {
     return vec2_scalar(a.x - b, a.y - b);
   }
+  friend vec2_scalar operator-(float a, vec2_scalar b) {
+    return vec2_scalar(a - b.x, a - b.y);
+  }
   friend vec2_scalar operator+(vec2_scalar a, vec2_scalar b) {
     return vec2_scalar(a.x + b.x, a.y + b.y);
   }
@@ -1742,6 +1745,9 @@ struct vec4_scalar {
   friend vec4_scalar operator*(vec4_scalar a, float b) {
     return vec4_scalar{a.x * b, a.y * b, a.z * b, a.w * b};
   }
+  friend vec4_scalar operator*(float a, vec4_scalar b) {
+    return vec4_scalar{a * b.x, a * b.y, a * b.z, a * b.w};
+  }
   vec4_scalar& operator*=(float a) {
     x *= a;
     y *= a;