gpu: pack 2D transforms in vec4 values

Instead of separate 2d scale and transform, pack them into a single
4d value.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/shaders/intersect.vert

@@ -8,8 +8,7 @@ layout(location = 0) in vec2 pos;
 layout(location = 1) in vec2 uv;
 
 layout(binding = 0) uniform Block {
-	vec2 scale;
-	vec2 offset;
+	vec4 uvTransform;
 };
 
 layout(location = 0) out vec2 vUV;
@@ -18,5 +17,5 @@ void main() {
   vec2 p = pos;
   p.y = -p.y;
   gl_Position = vec4(p, 0, 1);
-  vUV = uv*scale + offset;
+  vUV = uv*uvTransform.xy + uvTransform.zw;
 }