servo/components/script/dom/webglrenderingcontext.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use canvas::webgl_paint_task::WebGLPaintTask;
use canvas_traits::{CanvasMsg, CanvasWebGLMsg, CanvasCommonMsg};
use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding;
use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::{
    WebGLContextAttributes, WebGLRenderingContextMethods, WebGLRenderingContextConstants};
use dom::bindings::global::{GlobalRef, GlobalField};
use dom::bindings::js::{JS, JSRef, LayoutJS, Temporary};
use dom::bindings::utils::{Reflector, reflect_dom_object};
use dom::bindings::conversions::ToJSValConvertible;
use dom::htmlcanvaselement::{HTMLCanvasElement};
use dom::webglbuffer::{WebGLBuffer, WebGLBufferHelpers};
use dom::webglshader::{WebGLShader, WebGLShaderHelpers};
use dom::webglprogram::{WebGLProgram, WebGLProgramHelpers};
use dom::webgluniformlocation::{WebGLUniformLocation, WebGLUniformLocationHelpers};
use geom::size::Size2D;
use js::jsapi::{JSContext, JSObject};
use js::jsfriendapi::bindgen::{JS_GetFloat32ArrayData, JS_GetObjectAsArrayBufferView};
use js::jsval::{JSVal, NullValue, Int32Value};
use std::mem;
use std::ptr;
use std::sync::mpsc::{channel, Sender};
use util::str::DOMString;
use offscreen_gl_context::GLContextAttributes;

#[dom_struct]
pub struct WebGLRenderingContext {
    reflector_: Reflector,
    global: GlobalField,
    renderer: Sender<CanvasMsg>,
    canvas: JS<HTMLCanvasElement>,
}

impl WebGLRenderingContext {
    fn new_inherited(global: GlobalRef,
                     canvas: JSRef<HTMLCanvasElement>,
                     size: Size2D<i32>,
                     attrs: GLContextAttributes)
                     -> Result<WebGLRenderingContext, &'static str> {
        let chan = try!(WebGLPaintTask::start(size, attrs));

        Ok(WebGLRenderingContext {
            reflector_: Reflector::new(),
            global: GlobalField::from_rooted(&global),
            renderer: chan,
            canvas: JS::from_rooted(canvas),
        })
    }

    pub fn new(global: GlobalRef, canvas: JSRef<HTMLCanvasElement>, size: Size2D<i32>, attrs: GLContextAttributes)
               -> Option<Temporary<WebGLRenderingContext>> {
        match WebGLRenderingContext::new_inherited(global, canvas, size, attrs) {
            Ok(ctx) => Some(reflect_dom_object(box ctx, global,
                                               WebGLRenderingContextBinding::Wrap)),
            Err(msg) => {
                error!("Couldn't create WebGLRenderingContext: {}", msg);
                None
            }
        }
    }

    pub fn recreate(&self, size: Size2D<i32>) {
        self.renderer.send(CanvasMsg::Common(CanvasCommonMsg::Recreate(size))).unwrap();
    }
}

impl Drop for WebGLRenderingContext {
    fn drop(&mut self) {
        self.renderer.send(CanvasMsg::Common(CanvasCommonMsg::Close)).unwrap();
    }
}

impl<'a> WebGLRenderingContextMethods for JSRef<'a, WebGLRenderingContext> {
    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.1
    fn Canvas(self) -> Temporary<HTMLCanvasElement> {
        Temporary::from_rooted(self.canvas)
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.1
    fn DrawingBufferWidth(self) -> i32 {
        let (sender, receiver) = channel();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DrawingBufferWidth(sender))).unwrap();
        receiver.recv().unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.1
    fn DrawingBufferHeight(self) -> i32 {
        let (sender, receiver) = channel();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DrawingBufferHeight(sender))).unwrap();
        receiver.recv().unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3
    fn GetParameter(self, cx: *mut JSContext, parameter: u32) -> JSVal {
        // TODO(ecoal95): Implement the missing parameters from the spec
        match parameter {
            WebGLRenderingContextConstants::VERSION =>
                DOMString::from_str("WebGL 1.0").to_jsval(cx),
            WebGLRenderingContextConstants::RENDERER |
            WebGLRenderingContextConstants::VENDOR =>
                DOMString::from_str("Mozilla/Servo").to_jsval(cx),
            _ => NullValue(),
        }
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.2
    fn GetContextAttributes(self) -> Option<WebGLContextAttributes> {
        let (sender, receiver) = channel();

        // If the send does not succeed, assume context lost
        if let Err(_) = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetContextAttributes(sender))) {
            return None;
        }
        let attrs = receiver.recv().unwrap();

        Some(WebGLContextAttributes {
            alpha: attrs.alpha,
            antialias: attrs.antialias,
            depth: attrs.depth,
            failIfMajorPerformanceCaveat: false,
            preferLowPowerToHighPerformance: false,
            premultipliedAlpha: attrs.premultiplied_alpha,
            preserveDrawingBuffer: attrs.preserve_drawing_buffer,
            stencil: attrs.stencil
        })
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn AttachShader(self, program: Option<JSRef<WebGLProgram>>, shader: Option<JSRef<WebGLShader>>) {
        let program_id = match program {
            Some(program) => program.get_id(),
            None => return,
        };
        let shader_id = match shader {
            Some(shader) => shader.get_id(),
            None => return,
        };
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::AttachShader(program_id, shader_id))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.5
    fn BindBuffer(self, buffer_type: u32, buffer: Option<JSRef<WebGLBuffer>>) {
        let buffer_id = match buffer {
            Some(buffer) => buffer.get_id(),
            None => return,
        };
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::BindBuffer(buffer_type, buffer_id))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.5
    #[allow(unsafe_code)]
    fn BufferData(self, cx: *mut JSContext, target: u32, data: Option<*mut JSObject>, usage: u32) {
        let data = match data {
            Some(data) => data,
            None => return,
        };
        let data_vec;
        unsafe {
            let mut length = 0;
            let mut ptr = ptr::null_mut();
            let buffer_data = JS_GetObjectAsArrayBufferView(cx, data, &mut length, &mut ptr);
            if buffer_data.is_null() {
                panic!("Argument data to WebGLRenderingContext.bufferdata is not a Float32Array")
            }
            let data_f32 = JS_GetFloat32ArrayData(buffer_data, cx);
            let data_vec_length = length / mem::size_of::<f32>() as u32;
            data_vec = Vec::from_raw_buf(data_f32, data_vec_length as usize);
        }
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::BufferData(target, data_vec, usage))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.11
    fn Clear(self, mask: u32) {
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::Clear(mask))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3
    fn ClearColor(self, red: f32, green: f32, blue: f32, alpha: f32) {
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::ClearColor(red, green, blue, alpha))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn CompileShader(self, shader: Option<JSRef<WebGLShader>>) {
        let shader_id = match shader {
            Some(shader) => shader.get_id(),
            None => return,
        };
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CompileShader(shader_id))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.5
    fn CreateBuffer(self) -> Option<Temporary<WebGLBuffer>> {
        let (sender, receiver) = channel::<u32>();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CreateBuffer(sender))).unwrap();
        Some(WebGLBuffer::new(self.global.root().r(), receiver.recv().unwrap()))
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn CreateProgram(self) -> Option<Temporary<WebGLProgram>> {
        let (sender, receiver) = channel::<u32>();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CreateProgram(sender))).unwrap();
        Some(WebGLProgram::new(self.global.root().r(), receiver.recv().unwrap()))
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn CreateShader(self, shader_type: u32) -> Option<Temporary<WebGLShader>> {
        let (sender, receiver) = channel::<u32>();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CreateShader(shader_type, sender))).unwrap();
        Some(WebGLShader::new(self.global.root().r(), receiver.recv().unwrap()))
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.11
    fn DrawArrays(self, mode: u32, first: i32, count: i32) {
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DrawArrays(mode, first, count))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
    fn EnableVertexAttribArray(self, attrib_id: u32) {
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::EnableVertexAttribArray(attrib_id))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
    fn GetAttribLocation(self, program: Option<JSRef<WebGLProgram>>, name: DOMString) -> i32 {
        let program_id = match program {
            Some(program) => program.get_id(),
            None => return -1,
        };
        let (sender, receiver) = channel::<i32>();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetAttribLocation(program_id, name, sender))).unwrap();
        receiver.recv().unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn GetShaderInfoLog(self, shader: Option<JSRef<WebGLShader>>) -> Option<DOMString> {
        let shader_id = match shader {
            Some(shader) => shader.get_id(),
            None => return None,
        };
        let (sender, receiver) = channel::<String>();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetShaderInfoLog(shader_id, sender))).unwrap();
        let info = receiver.recv().unwrap();
        Some(info)
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn GetShaderParameter(self, _: *mut JSContext, shader: Option<JSRef<WebGLShader>>, param_id: u32) -> JSVal {
        let shader_id = match shader {
            Some(shader) => shader.get_id(),
            None => return NullValue(),
        };
        let (sender, receiver) = channel::<i32>();
        let msg = CanvasMsg::WebGL(CanvasWebGLMsg::GetShaderParameter(shader_id, param_id, sender));
        self.renderer.send(msg).unwrap();
        Int32Value(receiver.recv().unwrap())
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
    fn GetUniformLocation(self,
                          program: Option<JSRef<WebGLProgram>>,
                          name: DOMString) -> Option<Temporary<WebGLUniformLocation>> {
        let program_id = match program {
            Some(program) => program.get_id(),
            None => return None,
        };
        let (sender, receiver) = channel::<u32>();
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetUniformLocation(program_id, name, sender))).unwrap();
        Some(WebGLUniformLocation::new(self.global.root().r(), receiver.recv().unwrap()))
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn LinkProgram(self, program: Option<JSRef<WebGLProgram>>) {
        let program_id = match program {
            Some(program) => program.get_id(),
            None => return,
        };
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::LinkProgram(program_id))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn ShaderSource(self, shader: Option<JSRef<WebGLShader>>, source: DOMString) {
        let shader_id = match shader {
            Some(shader) => shader.get_id(),
            None => return,
        };
        let source_lines: Vec<String> = source.trim()
                                              .split(|c: char| c == '\n')
                                              .map(|line: &str| String::from_str(line) + "\n")
                                              .collect();
        let msg = CanvasMsg::WebGL(CanvasWebGLMsg::ShaderSource(shader_id, source_lines));
        self.renderer.send(msg).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
    #[allow(unsafe_code)]
    fn Uniform4fv(self,
                  cx: *mut JSContext,
                  uniform: Option<JSRef<WebGLUniformLocation>>,
                  data: Option<*mut JSObject>) {
        let uniform_id = match uniform {
            Some(uniform) => uniform.get_id(),
            None => return,
        };
        let data = match data {
            Some(data) => data,
            None => return,
        };
        let data_vec: Vec<f32>;
        unsafe {
            let data_f32 = JS_GetFloat32ArrayData(data, cx);
            data_vec = Vec::from_raw_buf(data_f32, 4);
        }
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::Uniform4fv(uniform_id, data_vec))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
    fn UseProgram(self, program: Option<JSRef<WebGLProgram>>) {
        let program_id = match program {
            Some(program) => program.get_id(),
            None => return,
        };
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::UseProgram(program_id as u32))).unwrap()
    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
    fn VertexAttribPointer(self, attrib_id: u32, size: i32, data_type: u32,
                           normalized: bool, stride: i32, offset: i64) {
        match data_type {
            WebGLRenderingContextConstants::FLOAT => {
               let msg = CanvasMsg::WebGL(
                   CanvasWebGLMsg::VertexAttribPointer2f(attrib_id, size, normalized, stride, offset));
                self.renderer.send(msg).unwrap()
            }
            _ => panic!("VertexAttribPointer: Data Type not supported")
        }

    }

    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.4
    fn Viewport(self, x: i32, y: i32, width: i32, height: i32) {
        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::Viewport(x, y, width, height))).unwrap()
    }
}

pub trait LayoutCanvasWebGLRenderingContextHelpers {
    #[allow(unsafe_code)]
    unsafe fn get_renderer(&self) -> Sender<CanvasMsg>;
}

impl LayoutCanvasWebGLRenderingContextHelpers for LayoutJS<WebGLRenderingContext> {
    #[allow(unsafe_code)]
    unsafe fn get_renderer(&self) -> Sender<CanvasMsg> {
        (*self.unsafe_get()).renderer.clone()
    }
}