Full range wgpu partial fix (#2597)

* Full range HDR works?

* Fix full range for non-HDR

* Cleanup

* Adjust this note

* Fix CI

* Fix server

* Return fractions

alvr/client_core/resources/staging_fragment.glsl

@@ -3,9 +3,17 @@
 
 uniform samplerExternalOES tex;
 
+// Convert from limited colors to full
+const float LIMITED_MIN = 16.0 / 255.0;
+const float LIMITED_MAX = 235.0 / 255.0;
+
 in vec2 uv;
 out vec4 out_color;
 
 void main() {
-    out_color = texture(tex, uv);
+    vec3 color = texture(tex, uv).rgb;
+#ifdef FIX_LIMITED_RANGE
+    color = LIMITED_MIN + ((LIMITED_MAX - LIMITED_MIN) * color);
+#endif
+    out_color = vec4(color, 1.0);
 }

alvr/client_core/resources/stream.wgsl

@@ -4,11 +4,6 @@ const DIV1: f32 = 0.94786729857; // 1.0 / 1.055
 const THRESHOLD: f32 = 0.04045;
 const GAMMA: vec3f = vec3f(2.4);
 
-// Convert from limited colors to full
-const LIMITED_MIN: f32 = 0.06274509803; // 16.0 / 255.0
-const LIMITED_MAX: f32 = 0.92156862745; // 235.0 / 255.0
-
-override FIX_LIMITED_RANGE: bool;
 override ENABLE_SRGB_CORRECTION: bool;
 override ENCODING_GAMMA: f32;
 
@@ -118,11 +113,6 @@ fn fragment_main(@location(0) uv: vec2f) -> @location(0) vec4f {
 
     var color = textureSample(stream_texture, stream_sampler, corrected_uv).rgb;
 
-    if FIX_LIMITED_RANGE {
-        // For some reason, the encoder shifts full-range color into the negatives and over one.
-        color = LIMITED_MIN + ((LIMITED_MAX - LIMITED_MIN) * color);
-    }
-
     if ENABLE_SRGB_CORRECTION {
         let condition = vec3f(f32(color.r < THRESHOLD), f32(color.g < THRESHOLD), f32(color.b < THRESHOLD));
         let lowValues = color * DIV12;

alvr/client_core/src/graphics/staging.rs

@@ -62,14 +62,24 @@ impl StagingRenderer {
         context: Rc<GraphicsContext>,
         staging_textures: [gl::Texture; 2],
         view_resolution: UVec2,
+        fix_limited_range: bool,
     ) -> Self {
         let gl = &context.gl_context;
         context.make_current();
 
+        // Add #defines into the shader after the first line
+        let mut frag_lines: Vec<&str> = include_str!("../../resources/staging_fragment.glsl")
+            .lines()
+            .collect();
+        if fix_limited_range {
+            frag_lines.insert(1, "#line 0 1\n#define FIX_LIMITED_RANGE");
+        }
+        let frag_str = frag_lines.join("\n");
+
         let program = create_program(
             gl,
             include_str!("../../resources/staging_vertex.glsl"),
-            include_str!("../../resources/staging_fragment.glsl"),
+            frag_str.as_str(),
         );
 
         unsafe {

alvr/client_core/src/graphics/stream.rs

@@ -84,7 +84,6 @@ impl StreamRenderer {
                 "ENABLE_SRGB_CORRECTION".into(),
                 enable_srgb_correction.into(),
             ),
-            ("FIX_LIMITED_RANGE".into(), fix_limited_range.into()),
             ("ENCODING_GAMMA".into(), encoding_gamma.into()),
         ]);
 
@@ -203,6 +202,7 @@ impl StreamRenderer {
             Rc::clone(&context),
             staging_textures_gl.try_into().unwrap(),
             staging_resolution,
+            fix_limited_range,
         );
 
         Self {

alvr/client_openxr/src/stream.rs

@@ -33,6 +33,7 @@ const DECODER_MAX_TIMEOUT_MULTIPLIER: f32 = 0.8;
 pub struct ParsedStreamConfig {
     pub view_resolution: UVec2,
     pub refresh_rate_hint: f32,
+    pub use_full_range: bool,
     pub encoding_gamma: f32,
     pub enable_hdr: bool,
     pub passthrough: Option<PassthroughMode>,
@@ -50,6 +51,7 @@ impl ParsedStreamConfig {
         Self {
             view_resolution: config.negotiated_config.view_resolution,
             refresh_rate_hint: config.negotiated_config.refresh_rate_hint,
+            use_full_range: config.negotiated_config.use_full_range,
             encoding_gamma: config.negotiated_config.encoding_gamma,
             enable_hdr: config.negotiated_config.enable_hdr,
             passthrough: config.settings.video.passthrough.as_option().cloned(),
@@ -180,7 +182,7 @@ impl StreamContext {
             format,
             config.foveated_encoding_config.clone(),
             platform != Platform::Lynx && !((platform.is_pico()) && config.enable_hdr),
-            !config.enable_hdr,
+            config.use_full_range && !config.enable_hdr, // TODO: figure out why HDR doesn't need the limited range hackfix in staging?
             config.encoding_gamma,
             config.passthrough.clone(),
         );

alvr/packets/src/lib.rs

@@ -129,6 +129,7 @@ pub struct NegotiatedStreamingConfig {
     // This is needed to detect when to use SteamVR hand trackers. This does NOT imply if multimodal
     // input is supported
     pub use_multimodal_protocol: bool,
+    pub use_full_range: bool,
     pub encoding_gamma: f32,
     pub enable_hdr: bool,
     pub wired: bool,
@@ -173,6 +174,8 @@ pub fn decode_stream_config(packet: &StreamConfigPacket) -> Result<StreamConfig>
             .unwrap_or_else(|_| settings.video.foveated_encoding.enabled());
     let use_multimodal_protocol =
         json::from_value(negotiated_json["use_multimodal_protocol"].clone()).unwrap_or(false);
+    let use_full_range = json::from_value(negotiated_json["use_full_range"].clone())
+        .unwrap_or(settings.video.encoder_config.use_full_range);
     let encoding_gamma = json::from_value(negotiated_json["encoding_gamma"].clone()).unwrap_or(1.0);
     let enable_hdr = json::from_value(negotiated_json["enable_hdr"].clone()).unwrap_or(false);
     let wired = json::from_value(negotiated_json["wired"].clone())?;
@@ -186,6 +189,7 @@ pub fn decode_stream_config(packet: &StreamConfigPacket) -> Result<StreamConfig>
             game_audio_sample_rate,
             enable_foveated_encoding,
             use_multimodal_protocol,
+            use_full_range,
             encoding_gamma,
             enable_hdr,
             wired,

alvr/server_core/src/connection.rs

@@ -766,6 +766,7 @@ fn connection_pipeline(
             game_audio_sample_rate,
             enable_foveated_encoding,
             use_multimodal_protocol: streaming_caps.multimodal_protocol,
+            use_full_range,
             encoding_gamma,
             enable_hdr,
             wired,