webgl: Add shader validation and translation

This commit adds angle-based validation and translation to WebGL
shaders.

The changes to the tex_image_2d test is neccessary (it was not valid
GLES 2.0 shader language).

components/canvas/webgl_paint_task.rs

@@ -112,14 +112,12 @@ impl WebGLPaintTask {
                 gl::enable_vertex_attrib_array(attrib_id),
             CanvasWebGLMsg::GetAttribLocation(program_id, name, chan) =>
                 self.get_attrib_location(program_id, name, chan),
-            CanvasWebGLMsg::GetShaderInfoLog(shader_id, chan) =>
-                self.get_shader_info_log(shader_id, chan),
             CanvasWebGLMsg::GetShaderParameter(shader_id, param_id, chan) =>
                 self.get_shader_parameter(shader_id, param_id, chan),
             CanvasWebGLMsg::GetUniformLocation(program_id, name, chan) =>
                 self.get_uniform_location(program_id, name, chan),
-            CanvasWebGLMsg::CompileShader(shader_id) =>
-                self.compile_shader(shader_id),
+            CanvasWebGLMsg::CompileShader(shader_id, source) =>
+                self.compile_shader(shader_id, source),
             CanvasWebGLMsg::CreateBuffer(chan) =>
                 self.create_buffer(chan),
             CanvasWebGLMsg::CreateFramebuffer(chan) =>
@@ -154,8 +152,6 @@ impl WebGLPaintTask {
                 gl::bind_texture(target, id),
             CanvasWebGLMsg::LinkProgram(program_id) =>
                 gl::link_program(program_id),
-            CanvasWebGLMsg::ShaderSource(shader_id, source) =>
-                gl::shader_source(shader_id, &[source.as_bytes()]),
             CanvasWebGLMsg::Uniform4fv(uniform_id, data) =>
                 gl::uniform_4f(uniform_id, data[0], data[1], data[2], data[3]),
             CanvasWebGLMsg::UseProgram(program_id) =>
@@ -303,11 +299,9 @@ impl WebGLPaintTask {
         gl::bind_framebuffer(target, id);
     }
 
-    // TODO(ecoal95): This is not spec-compliant, we must check
-    // the version of GLSL used. This functionality should probably
-    // be in the WebGLShader object
     #[inline]
-    fn compile_shader(&self, shader_id: u32) {
+    fn compile_shader(&self, shader_id: u32, source: String) {
+        gl::shader_source(shader_id, &[source.as_bytes()]);
         gl::compile_shader(shader_id);
     }
 
@@ -323,13 +317,6 @@ impl WebGLPaintTask {
         chan.send(attrib_location).unwrap();
     }
 
-    fn get_shader_info_log(&self, shader_id: u32, chan: IpcSender<Option<String>>) {
-        // TODO(ecoal95): Right now we always return a value, we should
-        // check for gl errors and return None there
-        let info = gl::get_shader_info_log(shader_id);
-        chan.send(Some(info)).unwrap();
-    }
-
     fn get_shader_parameter(&self,
                             shader_id: u32,
                             param_id: u32,

components/canvas_traits/lib.rs

@@ -138,7 +138,7 @@ pub enum CanvasWebGLMsg {
     DepthRange(f64, f64),
     Enable(u32),
     Disable(u32),
-    CompileShader(u32),
+    CompileShader(u32, String),
     CreateBuffer(IpcSender<Option<NonZero<u32>>>),
     CreateFramebuffer(IpcSender<Option<NonZero<u32>>>),
     CreateRenderbuffer(IpcSender<Option<NonZero<u32>>>),
@@ -157,7 +157,6 @@ pub enum CanvasWebGLMsg {
     BindTexture(u32, u32),
     DrawArrays(u32, i32, i32),
     EnableVertexAttribArray(u32),
-    GetShaderInfoLog(u32, IpcSender<Option<String>>),
     GetShaderParameter(u32, u32, IpcSender<WebGLShaderParameter>),
     GetAttribLocation(u32, String, IpcSender<Option<i32>>),
     GetUniformLocation(u32, String, IpcSender<Option<i32>>),
@@ -166,7 +165,6 @@ pub enum CanvasWebGLMsg {
     LineWidth(f32),
     PixelStorei(u32, i32),
     LinkProgram(u32),
-    ShaderSource(u32, String),
     Uniform4fv(i32, Vec<f32>),
     UseProgram(u32),
     VertexAttribPointer2f(u32, i32, bool, i32, u32),

components/script/Cargo.toml

@@ -55,6 +55,10 @@ features = ["query_encoding", "serde_serialization"]
 [dependencies.offscreen_gl_context]
 git = "https://github.com/ecoal95/rust-offscreen-rendering-context"
 
+[dependencies.angle]
+git = "https://github.com/ecoal95/angle"
+branch = "servo"
+
 [dependencies.cssparser]
 version = "0.3"
 features = [ "serde-serialization" ]

components/script/dom/webglshader.rs

@@ -11,10 +11,19 @@ use dom::webglobject::WebGLObject;
 
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
 
+use angle::hl::{BuiltInResources, Output, ShaderValidator};
 use canvas_traits::{CanvasMsg, CanvasWebGLMsg, WebGLResult, WebGLError, WebGLShaderParameter};
 use ipc_channel::ipc::{self, IpcSender};
 use std::cell::Cell;
 use std::cell::RefCell;
+use std::sync::{Once, ONCE_INIT};
+
+#[derive(Clone, Copy, PartialEq, Debug, JSTraceable, HeapSizeOf)]
+pub enum ShaderCompilationStatus {
+    NotCompiled,
+    Succeeded,
+    Failed,
+}
 
 #[dom_struct]
 pub struct WebGLShader {
@@ -22,20 +31,32 @@ pub struct WebGLShader {
     id: u32,
     gl_type: u32,
     source: RefCell<Option<String>>,
+    info_log: RefCell<Option<String>>,
     is_deleted: Cell<bool>,
-    // TODO(ecoal95): Evaluate moving this to `WebGLObject`
+    compilation_status: Cell<ShaderCompilationStatus>,
     #[ignore_heap_size_of = "Defined in ipc-channel"]
     renderer: IpcSender<CanvasMsg>,
 }
 
+#[cfg(not(target_os = "android"))]
+const SHADER_OUTPUT_FORMAT: Output = Output::Glsl;
+
+#[cfg(target_os = "android")]
+const SHADER_OUTPUT_FORMAT: Output = Output::Essl;
+
+static GLSLANG_INITIALIZATION: Once = ONCE_INIT;
+
 impl WebGLShader {
     fn new_inherited(renderer: IpcSender<CanvasMsg>, id: u32, shader_type: u32) -> WebGLShader {
+        GLSLANG_INITIALIZATION.call_once(|| ::angle::hl::initialize().unwrap());
         WebGLShader {
             webgl_object: WebGLObject::new_inherited(),
             id: id,
             gl_type: shader_type,
             source: RefCell::new(None),
+            info_log: RefCell::new(None),
             is_deleted: Cell::new(false),
+            compilation_status: Cell::new(ShaderCompilationStatus::NotCompiled),
             renderer: renderer,
         }
     }
@@ -69,10 +90,33 @@ impl WebGLShader {
         self.gl_type
     }
 
-    // TODO(ecoal95): Validate shaders to be conforming to the WebGL spec
     /// glCompileShader
     pub fn compile(&self) {
-        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CompileShader(self.id))).unwrap()
+        if self.compilation_status.get() != ShaderCompilationStatus::NotCompiled {
+            debug!("Compiling already compiled shader {}", self.id);
+        }
+
+        if let Some(ref source) = *self.source.borrow() {
+            let validator = ShaderValidator::for_webgl(self.gl_type,
+                                                       SHADER_OUTPUT_FORMAT,
+                                                       &BuiltInResources::default()).unwrap();
+            match validator.compile_and_translate(&[source.as_bytes()]) {
+                Ok(translated_source) => {
+                    // NOTE: At this point we should be pretty sure that the compilation in the paint task
+                    // will succeed.
+                    // It could be interesting to retrieve the info log from the paint task though
+                    let msg = CanvasWebGLMsg::CompileShader(self.id, translated_source);
+                    self.renderer.send(CanvasMsg::WebGL(msg)).unwrap();
+                    self.compilation_status.set(ShaderCompilationStatus::Succeeded);
+                },
+                Err(error) => {
+                    self.compilation_status.set(ShaderCompilationStatus::Failed);
+                    debug!("Shader {} compilation failed: {}", self.id, error);
+                },
+            }
+
+            *self.info_log.borrow_mut() = Some(validator.info_log());
+        }
     }
 
     /// Mark this shader as deleted (if it wasn't previously)
@@ -86,9 +130,7 @@ impl WebGLShader {
 
     /// glGetShaderInfoLog
     pub fn info_log(&self) -> Option<String> {
-        let (sender, receiver) = ipc::channel().unwrap();
-        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetShaderInfoLog(self.id, sender))).unwrap();
-        receiver.recv().unwrap()
+        self.info_log.borrow().clone()
     }
 
     /// glGetShaderParameter
@@ -110,7 +152,6 @@ impl WebGLShader {
 
     /// glShaderSource
     pub fn set_source(&self, source: String) {
-        *self.source.borrow_mut() = Some(source.clone());
-        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::ShaderSource(self.id, source))).unwrap()
+        *self.source.borrow_mut() = Some(source);
     }
 }

components/script/lib.rs

@@ -78,6 +78,7 @@ extern crate url;
 extern crate uuid;
 extern crate string_cache;
 extern crate offscreen_gl_context;
+extern crate angle;
 extern crate tendril;
 
 pub mod cors;

components/servo/Cargo.lock

@@ -56,6 +56,14 @@ name = "android_glue"
 version = "0.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "angle"
+version = "0.1.0"
+source = "git+https://github.com/ecoal95/angle?branch=servo#77288884bd7a89bf3019ca94dcda6c94cb178aa4"
+dependencies = [
+ "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "aster"
 version = "0.4.1"
@@ -1349,6 +1357,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "script"
 version = "0.0.1"
 dependencies = [
+ "angle 0.1.0 (git+https://github.com/ecoal95/angle?branch=servo)",
  "bitflags 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas 0.0.1",
  "canvas_traits 0.0.1",

ports/cef/Cargo.lock

@@ -55,6 +55,14 @@ name = "android_glue"
 version = "0.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "angle"
+version = "0.1.0"
+source = "git+https://github.com/ecoal95/angle?branch=servo#77288884bd7a89bf3019ca94dcda6c94cb178aa4"
+dependencies = [
+ "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "aster"
 version = "0.4.1"
@@ -1327,6 +1335,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "script"
 version = "0.0.1"
 dependencies = [
+ "angle 0.1.0 (git+https://github.com/ecoal95/angle?branch=servo)",
  "bitflags 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas 0.0.1",
  "canvas_traits 0.0.1",

ports/gonk/Cargo.lock

@@ -41,6 +41,14 @@ dependencies = [
  "memchr 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "angle"
+version = "0.1.0"
+source = "git+https://github.com/ecoal95/angle?branch=servo#77288884bd7a89bf3019ca94dcda6c94cb178aa4"
+dependencies = [
+ "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "aster"
 version = "0.4.1"
@@ -1193,6 +1201,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "script"
 version = "0.0.1"
 dependencies = [
+ "angle 0.1.0 (git+https://github.com/ecoal95/angle?branch=servo)",
  "bitflags 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas 0.0.1",
  "canvas_traits 0.0.1",

tests/ref/webgl-context/tex_image_2d_simple.html

@@ -10,6 +10,7 @@
   </style>
   <canvas id="c" width="256" height="256"></canvas>
   <script id="vertex_shader" type="x-shader/x-vertex">
+  precision mediump float;
   attribute vec2 a_texCoord;
   attribute vec2 a_position;
   varying vec2 v_texCoord;
@@ -21,6 +22,7 @@
   </script>
 
   <script id="fragment_shader" type="x-shader/x-fragment">
+  precision mediump float;
   uniform sampler2D u_image;
   varying vec2 v_texCoord;
   void main() {