Rename delete_program to delete_shader (add delete_shader, delete_pip…

…eline to the metal backend as place holder)

src/graphics.rs

@@ -1251,7 +1251,7 @@ pub trait RenderingBackend {
     ///
     /// There is no protection against using deleted programs later. However its not a CPU-level Porgram and thats why
     /// this function is not marked as unsafe
-    fn delete_program(&mut self, program: ShaderId);
+    fn delete_shader(&mut self, program: ShaderId);
 
     /// Set a new viewport rectangle.
     /// Should be applied after begin_pass.

src/graphics/gl.rs

@@ -819,7 +819,7 @@ impl RenderingBackend for GlContext {
         t.delete();
     }
 
-    fn delete_program(&mut self, program: ShaderId) {
+    fn delete_shader(&mut self, program: ShaderId) {
         unsafe { glDeleteProgram(self.shaders[program.0].program) };
         self.shaders.remove(program.0);
         self.cache.cur_pipeline = None;

src/graphics/metal.rs

@@ -1248,6 +1248,8 @@ impl RenderingBackend for MetalContext {
         }
     }
 
+    fn delete_shader(&mut self, shader: ShaderId) {}
+    fn delete_pipeline(&mut self, pipeline: Pipeline) {}
     fn commit_frame(&mut self) {
         unsafe {
             assert!(!self.command_queue.is_null());