External gles framebuffer (#7671)

wgpu-hal/src/gles/command.rs

@@ -523,6 +523,8 @@ impl crate::CommandEncoder for super::CommandEncoder {
             .any(|at| match at.target.view.inner {
                 #[cfg(webgl)]
                 super::TextureInner::ExternalFramebuffer { .. } => true,
+                #[cfg(native)]
+                super::TextureInner::ExternalNativeFramebuffer { .. } => true,
                 _ => false,
             });
 

wgpu-hal/src/gles/device.rs

@@ -969,6 +969,8 @@ impl crate::Device for super::Device {
                 }
                 #[cfg(webgl)]
                 super::TextureInner::ExternalFramebuffer { .. } => {}
+                #[cfg(native)]
+                super::TextureInner::ExternalNativeFramebuffer { .. } => {}
             }
         }
 

wgpu-hal/src/gles/mod.rs

@@ -366,9 +366,21 @@ pub enum TextureInner {
         target: BindTarget,
     },
     #[cfg(webgl)]
+    /// Render to a `WebGLFramebuffer`
+    ///
+    /// This is a web feature
     ExternalFramebuffer {
         inner: web_sys::WebGlFramebuffer,
     },
+    #[cfg(native)]
+    /// Render to a `glow::NativeFramebuffer`
+    /// Useful when the framebuffer to draw to
+    /// has a non-zero framebuffer ID
+    ///
+    /// This is a native feature
+    ExternalNativeFramebuffer {
+        inner: glow::NativeFramebuffer,
+    },
 }
 
 #[cfg(send_sync)]
@@ -385,6 +397,8 @@ impl TextureInner {
             Self::Texture { raw, target } => (raw, target),
             #[cfg(webgl)]
             Self::ExternalFramebuffer { .. } => panic!("Unexpected external framebuffer"),
+            #[cfg(native)]
+            Self::ExternalNativeFramebuffer { .. } => panic!("unexpected external framebuffer"),
         }
     }
 }

wgpu-hal/src/gles/queue.rs

@@ -158,6 +158,10 @@ impl super::Queue {
             super::TextureInner::ExternalFramebuffer { ref inner } => unsafe {
                 gl.bind_external_framebuffer(glow::FRAMEBUFFER, inner);
             },
+            #[cfg(native)]
+            super::TextureInner::ExternalNativeFramebuffer { ref inner } => unsafe {
+                gl.bind_framebuffer(glow::FRAMEBUFFER, Some(*inner));
+            },
         }
     }