Add convenience function for graphics pipe

vulkan-rs/src/pipelines/graphics_pipeline.rs

@@ -307,6 +307,21 @@ impl GraphicsPipelineBuilder {
         self
     }
 
+    pub fn whole_area(self, width: u32, height: u32) -> Self {
+        self.add_viewport(VkViewport {
+            x: 0.0,
+            y: 0.0,
+            width: width as f32,
+            height: height as f32,
+            minDepth: 0.0,
+            maxDepth: 1.0,
+        })
+        .add_scissor(VkRect2D {
+            offset: VkOffset2D { x: 0, y: 0 },
+            extent: VkExtent2D { width, height },
+        })
+    }
+
     pub fn build(
         mut self,
         device: Arc<Device>,