IodineGBAGraphicsGlueCode.js

"use strict";
/*
 Copyright (C) 2012-2014 Grant Galitz
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
function GlueCodeGfx() {
    this.didRAF = false;                      //Set when rAF has been used.
    this.graphicsFound = 0;                   //Do we have graphics output sink found yet?
    this.offscreenWidth = 240;                //Width of the GBA screen.
    this.offscreenHeight = 160;               //Height of the GBA screen.
    this.doSmoothing = true;
    //Cache some frame buffer lengths:
    var offscreenRGBCount = this.offscreenWidth * this.offscreenHeight * 3;
    this.swizzledFrameFree = [getUint8Array(offscreenRGBCount), getUint8Array(offscreenRGBCount)];
    this.swizzledFrameReady = [];
    this.initializeGraphicsBuffer();          //Pre-set the swizzled buffer for first frame.
}
GlueCodeGfx.prototype.attachCanvas = function (canvas) {
    this.canvas = canvas;
    this.graphicsFound = this.initializeCanvasTarget();
    this.setSmoothScaling(this.doSmoothing);
}
GlueCodeGfx.prototype.detachCanvas = function () {
    this.canvas = null;
}
GlueCodeGfx.prototype.recomputeDimension = function () {
    //Cache some dimension info:
    this.canvasLastWidth = this.canvas.clientWidth;
    this.canvasLastHeight = this.canvas.clientHeight;
    if (window.mozRequestAnimationFrame) {    //Sniff out firefox for selecting this path.
        //Set target as unscaled:
        this.onscreenWidth = this.canvas.width = this.offscreenWidth;
        this.onscreenHeight = this.canvas.height = this.offscreenHeight;
    }
    else {
        //Set target canvas as scaled:
        this.onscreenWidth = this.canvas.width = this.canvas.clientWidth;
        this.onscreenHeight = this.canvas.height = this.canvas.clientHeight;
    }
}
GlueCodeGfx.prototype.initializeCanvasTarget = function () {
    try {
        //Obtain dimensional information:
        this.recomputeDimension();
        //Get handles on the canvases:
        this.canvasOffscreen = document.createElement("canvas");
        this.canvasOffscreen.width = this.offscreenWidth;
        this.canvasOffscreen.height = this.offscreenHeight;
        this.drawContextOffscreen = this.canvasOffscreen.getContext("2d");
        this.drawContextOnscreen = this.canvas.getContext("2d");
        //Get a CanvasPixelArray buffer:
        this.canvasBuffer = this.getBuffer(this.drawContextOffscreen, this.offscreenWidth, this.offscreenHeight);
        //Initialize Alpha Channel:
        this.initializeAlpha(this.canvasBuffer.data);
        //Draw swizzled buffer out as a test:
        this.requestDraw();
        this.checkRAF();
        //Success:
        return true;
    }
    catch (error) {
        //Failure:
        return false;
    }
}
GlueCodeGfx.prototype.setSmoothScaling = function (doSmoothing) {
    this.doSmoothing = doSmoothing;
    if (this.graphicsFound) {
        this.canvas.setAttribute("style", (this.canvas.getAttribute("style") || "") + "; image-rendering: " + ((doSmoothing) ? "auto" : "-webkit-optimize-contrast") + ";" +
            "image-rendering: " + ((doSmoothing) ? "optimizeQuality" : "-o-crisp-edges") + ";" +
            "image-rendering: " + ((doSmoothing) ? "optimizeQuality" : "-moz-crisp-edges") + ";" +
            "-ms-interpolation-mode: " + ((doSmoothing) ? "bicubic" : "nearest-neighbor") + ";");
        this.drawContextOnscreen.mozImageSmoothingEnabled = doSmoothing;
        this.drawContextOnscreen.webkitImageSmoothingEnabled = doSmoothing;
        this.drawContextOnscreen.imageSmoothingEnabled = doSmoothing;
    }
}
GlueCodeGfx.prototype.initializeAlpha = function (canvasData) {
    var length = canvasData.length;
    for (var indexGFXIterate = 3; indexGFXIterate < length; indexGFXIterate += 4) {
        canvasData[indexGFXIterate] = 0xFF;
    }
}
GlueCodeGfx.prototype.getBuffer = function (canvasContext, width, height) {
    //Get a CanvasPixelArray buffer:
    var buffer = null;
    try {
        buffer = this.drawContextOffscreen.createImageData(width, height);
    }
    catch (error) {
        buffer = this.drawContextOffscreen.getImageData(0, 0, width, height);
    }
    return buffer;
}
GlueCodeGfx.prototype.copyBuffer = function (buffer) {
    if (this.graphicsFound) {
        if (this.swizzledFrameFree.length == 0) {
            if (this.didRAF) {
                this.requestDrawSingle();
            }
            else {
                this.swizzledFrameFree.push(this.swizzledFrameReady.shift());
            }
        }
        var swizzledFrame = this.swizzledFrameFree.shift();
        var length = swizzledFrame.length;
        if (buffer.buffer) {
            swizzledFrame.set(buffer);
        }
        else {
            for (var bufferIndex = 0; bufferIndex < length; ++bufferIndex) {
                swizzledFrame[bufferIndex] = buffer[bufferIndex];
            }
        }
        this.swizzledFrameReady.push(swizzledFrame);
        if (!window.requestAnimationFrame) {
            this.requestDraw();
        }
        else if (!this.didRAF) {
            //Prime RAF draw:
            var parentObj = this;
            window.requestAnimationFrame(function () {
                if (parentObj.canvas) {
                    parentObj.requestRAFDraw();
                }
            });
        }
    }
}
GlueCodeGfx.prototype.requestRAFDraw = function () {
    this.didRAF = true;
    this.requestDraw();
}
GlueCodeGfx.prototype.requestDrawSingle = function () {
    if (this.swizzledFrameReady.length > 0) {
        var canvasData = this.canvasBuffer.data;
        var bufferIndex = 0;
        var swizzledFrame = this.swizzledFrameReady.shift();
        var length = canvasData.length;
        for (var canvasIndex = 0; canvasIndex < length; ++canvasIndex) {
            canvasData[canvasIndex++] = swizzledFrame[bufferIndex++];
            canvasData[canvasIndex++] = swizzledFrame[bufferIndex++];
            canvasData[canvasIndex++] = swizzledFrame[bufferIndex++];
        }
        this.swizzledFrameFree.push(swizzledFrame);
        this.graphicsBlit();
    }
}
GlueCodeGfx.prototype.requestDraw = function () {
    this.requestDrawSingle();
    if (this.didRAF) {
        var parentObj = this;
        window.requestAnimationFrame(function () {
            if (parentObj.canvas) {
                parentObj.requestDraw();
            }
        });
    }
}
GlueCodeGfx.prototype.graphicsBlit = function () {
    if (this.canvasLastWidth != this.canvas.clientWidth || this.canvasLastHeight != this.canvas.clientHeight) {
        this.recomputeDimension();
        this.setSmoothScaling(this.doSmoothing);
    }
    if (this.offscreenWidth == this.onscreenWidth && this.offscreenHeight == this.onscreenHeight) {
        //Canvas does not need to scale, draw directly to final:
        this.drawContextOnscreen.putImageData(this.canvasBuffer, 0, 0);
    }
    else {
        //Canvas needs to scale, draw to offscreen first:
        this.drawContextOffscreen.putImageData(this.canvasBuffer, 0, 0);
        //Scale offscreen canvas image onto the final:
        this.drawContextOnscreen.drawImage(this.canvasOffscreen, 0, 0, this.onscreenWidth, this.onscreenHeight);
    }
}
GlueCodeGfx.prototype.initializeGraphicsBuffer = function () {
    //Initialize the first frame to a white screen:
    var swizzledFrame = this.swizzledFrameFree.shift();
    var length = swizzledFrame.length;
    for (var bufferIndex = 0; bufferIndex < length; ++bufferIndex) {
        swizzledFrame[bufferIndex] = 0xF8;
    }
    this.swizzledFrameReady.push(swizzledFrame);
}
GlueCodeGfx.prototype.checkRAF = function () {
    window.requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame ||
    window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
}