Multiple changes + fixes

samples/basic_triangle/shaders/basic_triangle.vert

@@ -1,7 +1,7 @@
 #version 450
 #pragma shader_stage(vertex)
 
-// in layout(location=0) vec2 position;
+in layout(location=0) vec2 position;
 
 layout(set=0, binding=0) uniform data {
   vec4 positions[3];
@@ -12,4 +12,5 @@ void main() {
     // gl_Position = vec4(position, 0.0, 1.0);
     // gl_Position = vec4(inputData.positions[gl_VertexIndex], 0.0, 1.0);
     gl_Position = vertexData.positions[gl_VertexIndex];
-}
+    // gl_Position = vec4(position, 0.0, 1.0);
+}