gl: add Rgba16Float format support for color attachments (#3045)

Co-authored-by: Connor Fitzgerald <connorwadefitzgerald@gmail.com>

CHANGELOG.md

@@ -104,7 +104,7 @@ SurfaceConfiguration {
 - Fix bug where the Vulkan backend would panic when using a supported window and display handle but the
   dependent extensions are not available by @i509VCB in [#3054](https://github.com/gfx-rs/wgpu/pull/3054).
 
-#### Gles
+#### GLES
 - Report vendor id for Mesa and Apple GPUs. By @i509VCB [#3036](https://github.com/gfx-rs/wgpu/pull/3036)
 - Report Apple M2 gpu as integrated. By @i509VCB [#3036](https://github.com/gfx-rs/wgpu/pull/3036)
 
@@ -131,6 +131,7 @@ SurfaceConfiguration {
   is the actual version of the device. By @i509VCB in [#3011](https://github.com/gfx-rs/wgpu/pull/3011)
 
 #### GLES
+- Add `Rgba16Float` format support for color attachments. By @jinleili in [#3045](https://github.com/gfx-rs/wgpu/pull/3045)
 - `TEXTURE_COMPRESSION_ASTC_HDR` feature detection  by @jinleili in [#3042](https://github.com/gfx-rs/wgpu/pull/3042)
 
 ### Performance

wgpu-hal/src/gles/adapter.rs

@@ -785,9 +785,7 @@ impl crate::Adapter<super::Api> for super::Adapter {
         &self,
         surface: &super::Surface,
     ) -> Option<crate::SurfaceCapabilities> {
-        if surface.presentable {
-            Some(crate::SurfaceCapabilities {
-                formats: if surface.supports_srgb() {
+        let mut formats = if surface.supports_srgb() {
             vec![
                 wgt::TextureFormat::Rgba8UnormSrgb,
                 #[cfg(not(target_arch = "wasm32"))]
@@ -799,7 +797,17 @@ impl crate::Adapter<super::Api> for super::Adapter {
                 #[cfg(not(target_arch = "wasm32"))]
                 wgt::TextureFormat::Bgra8Unorm,
             ]
-                },
+        };
+        if self
+            .shared
+            .private_caps
+            .contains(super::PrivateCapabilities::COLOR_BUFFER_HALF_FLOAT)
+        {
+            formats.push(wgt::TextureFormat::Rgba16Float)
+        }
+        if surface.presentable {
+            Some(crate::SurfaceCapabilities {
+                formats,
                 present_modes: vec![wgt::PresentMode::Fifo], //TODO
                 composite_alpha_modes: vec![wgt::CompositeAlphaMode::Opaque], //TODO
                 swap_chain_sizes: 2..=2,