From 313b02d24f0beac85787a2d842ea2ac85e5541c2 Mon Sep 17 00:00:00 2001
From: Mike Welsh <mwelsh@gmail.com>
Date: Wed, 23 Sep 2020 14:41:27 -0700
Subject: [PATCH] webgl: Fall back to canvas if not using hardware acceleration

Display WebGL driver info, detect whether hardware acceleration
is enabled, and fall back to the canvas backend in this case.
---
 render/webgl/Cargo.toml |  6 +++---
 render/webgl/src/lib.rs | 15 ++++++++++++++-
 web/src/lib.rs          | 10 ++++++----
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/render/webgl/Cargo.toml b/render/webgl/Cargo.toml
index b0aed2f03..4aae31f0f 100644
--- a/render/webgl/Cargo.toml
+++ b/render/webgl/Cargo.toml
@@ -25,6 +25,6 @@ default-features = false
 
 [dependencies.web-sys]
 version = "0.3.45"
-features = ["HtmlCanvasElement", "HtmlElement", "Node", "OesVertexArrayObject", "WebGlBuffer", "WebGlFramebuffer", "WebGlProgram", 
-            "WebGlRenderbuffer", "WebGlRenderingContext", "WebGl2RenderingContext", "WebGlShader", "WebGlTexture", "WebGlUniformLocation", 
-            "WebGlVertexArrayObject"]
+features = ["HtmlCanvasElement", "HtmlElement", "Node", "OesVertexArrayObject", "WebGlBuffer", "WebglDebugRendererInfo",
+            "WebGlFramebuffer", "WebGlProgram", "WebGlRenderbuffer", "WebGlRenderingContext", "WebGl2RenderingContext",
+            "WebGlShader", "WebGlTexture", "WebGlUniformLocation", "WebGlVertexArrayObject"]
diff --git a/render/webgl/src/lib.rs b/render/webgl/src/lib.rs
index f7f4c235c..a92311f52 100644
--- a/render/webgl/src/lib.rs
+++ b/render/webgl/src/lib.rs
@@ -11,7 +11,7 @@ use wasm_bindgen::{JsCast, JsValue};
 use web_sys::{
     HtmlCanvasElement, OesVertexArrayObject, WebGl2RenderingContext as Gl2, WebGlBuffer,
     WebGlFramebuffer, WebGlProgram, WebGlRenderbuffer, WebGlRenderingContext as Gl, WebGlShader,
-    WebGlTexture, WebGlUniformLocation, WebGlVertexArrayObject,
+    WebGlTexture, WebGlUniformLocation, WebGlVertexArrayObject, WebglDebugRendererInfo,
 };
 
 type Error = Box<dyn std::error::Error>;
@@ -76,6 +76,7 @@ impl WebGlRenderBackend {
             ("alpha", JsValue::FALSE),
             ("antialias", JsValue::FALSE),
             ("depth", JsValue::FALSE),
+            ("failIfMajorPerformanceCaveat", JsValue::TRUE), // fail if no GPU available
         ];
         let context_options = js_sys::Object::new();
         for (name, value) in options.iter() {
@@ -141,6 +142,18 @@ impl WebGlRenderBackend {
             }
         };
 
+        // Get WebGL driver info.
+        let driver_info = if gl.get_extension("WEBGL_debug_renderer_info").is_ok() {
+            gl.get_parameter(WebglDebugRendererInfo::UNMASKED_RENDERER_WEBGL)
+                .ok()
+                .and_then(|val| val.as_string())
+                .unwrap_or_else(|| "<unknown>".to_string())
+        } else {
+            "<unknown>".to_string()
+        };
+
+        log::info!("WebGL graphics driver: {}", driver_info);
+
         let color_vertex = Self::compile_shader(&gl, Gl::VERTEX_SHADER, COLOR_VERTEX_GLSL)?;
         let texture_vertex = Self::compile_shader(&gl, Gl::VERTEX_SHADER, TEXTURE_VERTEX_GLSL)?;
         let color_fragment = Self::compile_shader(&gl, Gl::FRAGMENT_SHADER, COLOR_FRAGMENT_GLSL)?;
diff --git a/web/src/lib.rs b/web/src/lib.rs
index aab2ce21b..f954c3f0d 100644
--- a/web/src/lib.rs
+++ b/web/src/lib.rs
@@ -835,8 +835,9 @@ fn create_renderer(
             .into_js_result()?
             .dyn_into()
             .map_err(|_| "Expected HtmlCanvasElement")?;
-        if let Ok(renderer) = ruffle_render_webgl::WebGlRenderBackend::new(&canvas) {
-            return Ok((canvas, Box::new(renderer)));
+        match ruffle_render_webgl::WebGlRenderBackend::new(&canvas) {
+            Ok(renderer) => return Ok((canvas, Box::new(renderer))),
+            Err(error) => log::error!("Error creating WebGL renderer: {}", error),
         }
     }
 
@@ -848,8 +849,9 @@ fn create_renderer(
             .into_js_result()?
             .dyn_into()
             .map_err(|_| "Expected HtmlCanvasElement")?;
-        if let Ok(renderer) = ruffle_render_canvas::WebCanvasRenderBackend::new(&canvas) {
-            return Ok((canvas, Box::new(renderer)));
+        match ruffle_render_canvas::WebCanvasRenderBackend::new(&canvas) {
+            Ok(renderer) => return Ok((canvas, Box::new(renderer))),
+            Err(error) => log::error!("Error creating canvas renderer: {}", error),
         }
     }