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pixi.js / src / mesh / Mesh.js
@Grzegorz PrzybyƂowicz Grzegorz PrzybyƂowicz on 8 May 2015 10 KB Rope supports textures from spritheet
var core = require('../core');

/**
 * Base mesh class
 * @class
 * @extends Container
 * @memberof PIXI.mesh
 * @param texture {Texture} The texture to use
 * @param [vertices] {Float32Arrif you want to specify the vertices
 * @param [uvs] {Float32Array} if you want to specify the uvs
 * @param [indices] {Uint16Array} if you want to specify the indices
 * @param [drawMode] {number} the drawMode, can be any of the Mesh.DRAW_MODES consts
 */
function Mesh(texture, vertices, uvs, indices, drawMode)
{
    core.Container.call(this);

    /**
     * The texture of the Mesh
     *
     * @member {Texture}
     */
    this.texture = texture;

    /**
     * The Uvs of the Mesh
     *
     * @member {Float32Array}
     */
    this.uvs = uvs || new Float32Array([0, 1,
                                 1, 1,
                                 1, 0,
                                 0, 1]);

    /**
     * An array of vertices
     *
     * @member {Float32Array}
     */
    this.vertices = vertices || new Float32Array([0, 0,
                                      100, 0,
                                      100, 100,
                                      0, 100]);

    /*
     * @member {Uint16Array} An array containing the indices of the vertices
     */
    //  TODO auto generate this based on draw mode!
    this.indices = indices || new Uint16Array([0, 1, 2, 3]);

    /**
     * Whether the Mesh is dirty or not
     *
     * @member {boolean}
     */
    this.dirty = true;

    /**
     * The blend mode to be applied to the sprite. Set to blendModes.NORMAL to remove any blend mode.
     *
     * @member {number}
     * @default CONST.BLEND_MODES.NORMAL;
     */
    this.blendMode = core.BLEND_MODES.NORMAL;

    /**
     * Triangles in canvas mode are automatically antialiased, use this value to force triangles to overlap a bit with each other.
     *
     * @member {number}
     */
    this.canvasPadding = 0;

    /**
     * The way the Mesh should be drawn, can be any of the Mesh.DRAW_MODES consts
     *
     * @member {number}
     */
    this.drawMode = drawMode || Mesh.DRAW_MODES.TRIANGLE_MESH;
}

// constructor
Mesh.prototype = Object.create(core.Container.prototype);
Mesh.prototype.constructor = Mesh;
module.exports = Mesh;

/**
 * Renders the object using the WebGL renderer
 *
 * @param renderer {WebGLRenderer} a reference to the WebGL renderer
 * @private
 */
Mesh.prototype._renderWebGL = function (renderer)
{
    renderer.setObjectRenderer(renderer.plugins.mesh);
    renderer.plugins.mesh.render(this);
};

/**
 * Renders the object using the Canvas renderer
 *
 * @param renderer {CanvasRenderer}
 * @private
 */
Mesh.prototype._renderCanvas = function (renderer)
{
    var context = renderer.context;

    var transform = this.worldTransform;

    if (renderer.roundPixels)
    {
        context.setTransform(transform.a, transform.b, transform.c, transform.d, transform.tx | 0, transform.ty | 0);
    }
    else
    {
        context.setTransform(transform.a, transform.b, transform.c, transform.d, transform.tx, transform.ty);
    }

    if (this.drawMode === Mesh.DRAW_MODES.TRIANGLE_MESH)
    {
        this._renderCanvasTriangleMesh(context);
    }
    else
    {
        this._renderCanvasTriangles(context);
    }
};

/**
 * Draws the object in Triangle Mesh mode using canvas
 *
 * @param context {CanvasRenderingContext2D} the current drawing context
 * @private
 */
Mesh.prototype._renderCanvasTriangleMesh = function (context)
{
    // draw triangles!!
    var vertices = this.vertices;
    var uvs = this.uvs;

    var length = vertices.length / 2;
    // this.count++;

    for (var i = 0; i < length - 2; i++)
    {
        // draw some triangles!
        var index = i * 2;
        this._renderCanvasDrawTriangle(context, vertices, uvs, index, (index + 2), (index + 4));
    }
};

/**
 * Draws the object in triangle mode using canvas
 *
 * @param context {CanvasRenderingContext2D} the current drawing context
 * @private
 */
Mesh.prototype._renderCanvasTriangles = function (context)
{
    // draw triangles!!
    var vertices = this.vertices;
    var uvs = this.uvs;
    var indices = this.indices;

    var length = indices.length;
    // this.count++;

    for (var i = 0; i < length; i += 3)
    {
        // draw some triangles!
        var index0 = indices[i] * 2, index1 = indices[i + 1] * 2, index2 = indices[i + 2] * 2;
        this._renderCanvasDrawTriangle(context, vertices, uvs, index0, index1, index2);
    }
};

/**
 * Draws one of the triangles that form this Mesh
 *
 * @param context {CanvasRenderingContext2D} the current drawing context
 * @param vertices {Float32Array} a reference to the vertices of the Mesh
 * @param uvs {Float32Array} a reference to the uvs of the Mesh
 * @param index0 {number} the index of the first vertex
 * @param index1 {number} the index of the second vertex
 * @param index2 {number} the index of the third vertex
 * @private
 */
Mesh.prototype._renderCanvasDrawTriangle = function (context, vertices, uvs, index0, index1, index2)
{
    var textureSource = this.texture.baseTexture.source;
    var textureWidth = this.texture.baseTexture.width;
    var textureHeight = this.texture.baseTexture.height;

    var x0 = vertices[index0], x1 = vertices[index1], x2 = vertices[index2];
    var y0 = vertices[index0 + 1], y1 = vertices[index1 + 1], y2 = vertices[index2 + 1];

    var u0 = uvs[index0] * textureWidth, u1 = uvs[index1] * textureWidth, u2 = uvs[index2] * textureWidth;
    var v0 = uvs[index0 + 1] * textureHeight, v1 = uvs[index1 + 1] * textureHeight, v2 = uvs[index2 + 1] * textureHeight;

    if (this.canvasPadding > 0)
    {
        var paddingX = this.canvasPadding / this.worldTransform.a;
        var paddingY = this.canvasPadding / this.worldTransform.d;
        var centerX = (x0 + x1 + x2) / 3;
        var centerY = (y0 + y1 + y2) / 3;

        var normX = x0 - centerX;
        var normY = y0 - centerY;

        var dist = Math.sqrt(normX * normX + normY * normY);
        x0 = centerX + (normX / dist) * (dist + paddingX);
        y0 = centerY + (normY / dist) * (dist + paddingY);

        //

        normX = x1 - centerX;
        normY = y1 - centerY;

        dist = Math.sqrt(normX * normX + normY * normY);
        x1 = centerX + (normX / dist) * (dist + paddingX);
        y1 = centerY + (normY / dist) * (dist + paddingY);

        normX = x2 - centerX;
        normY = y2 - centerY;

        dist = Math.sqrt(normX * normX + normY * normY);
        x2 = centerX + (normX / dist) * (dist + paddingX);
        y2 = centerY + (normY / dist) * (dist + paddingY);
    }

    context.save();
    context.beginPath();


    context.moveTo(x0, y0);
    context.lineTo(x1, y1);
    context.lineTo(x2, y2);

    context.closePath();

    context.clip();

    // Compute matrix transform
    var delta =  (u0 * v1)      + (v0 * u2)      + (u1 * v2)      - (v1 * u2)      - (v0 * u1)      - (u0 * v2);
    var deltaA = (x0 * v1)      + (v0 * x2)      + (x1 * v2)      - (v1 * x2)      - (v0 * x1)      - (x0 * v2);
    var deltaB = (u0 * x1)      + (x0 * u2)      + (u1 * x2)      - (x1 * u2)      - (x0 * u1)      - (u0 * x2);
    var deltaC = (u0 * v1 * x2) + (v0 * x1 * u2) + (x0 * u1 * v2) - (x0 * v1 * u2) - (v0 * u1 * x2) - (u0 * x1 * v2);
    var deltaD = (y0 * v1)      + (v0 * y2)      + (y1 * v2)      - (v1 * y2)      - (v0 * y1)      - (y0 * v2);
    var deltaE = (u0 * y1)      + (y0 * u2)      + (u1 * y2)      - (y1 * u2)      - (y0 * u1)      - (u0 * y2);
    var deltaF = (u0 * v1 * y2) + (v0 * y1 * u2) + (y0 * u1 * v2) - (y0 * v1 * u2) - (v0 * u1 * y2) - (u0 * y1 * v2);

    context.transform(deltaA / delta, deltaD / delta,
        deltaB / delta, deltaE / delta,
        deltaC / delta, deltaF / delta);

    context.drawImage(textureSource, 0, 0);
    context.restore();
};



/**
 * Renders a flat Mesh
 *
 * @param Mesh {Mesh} The Mesh to render
 * @private
 */
Mesh.prototype.renderMeshFlat = function (Mesh)
{
    var context = this.context;
    var vertices = Mesh.vertices;

    var length = vertices.length/2;
    // this.count++;

    context.beginPath();
    for (var i=1; i < length-2; i++)
    {
        // draw some triangles!
        var index = i*2;

        var x0 = vertices[index],   x1 = vertices[index+2], x2 = vertices[index+4];
        var y0 = vertices[index+1], y1 = vertices[index+3], y2 = vertices[index+5];

        context.moveTo(x0, y0);
        context.lineTo(x1, y1);
        context.lineTo(x2, y2);
    }

    context.fillStyle = '#FF0000';
    context.fill();
    context.closePath();
};

/*
Mesh.prototype.setTexture = function (texture)
{
    //TODO SET THE TEXTURES
    //TODO VISIBILITY
    //TODO SETTER

    // stop current texture
    this.texture = texture;
    this.width   = texture.frame.width;
    this.height  = texture.frame.height;
    this.updateFrame = true;
};
 */

/**
 * When the texture is updated, this event will fire to update the scale and frame
 *
 * @param event
 * @private
 */

Mesh.prototype.onTextureUpdate = function ()
{
    this.updateFrame = true;
};

/**
 * Returns the bounds of the mesh as a rectangle. The bounds calculation takes the worldTransform into account.
 *
 * @param matrix {Matrix} the transformation matrix of the sprite
 * @return {Rectangle} the framing rectangle
 */
Mesh.prototype.getBounds = function (matrix)
{
    var worldTransform = matrix || this.worldTransform;

    var a = worldTransform.a;
    var b = worldTransform.b;
    var c = worldTransform.c;
    var d = worldTransform.d;
    var tx = worldTransform.tx;
    var ty = worldTransform.ty;

    var maxX = -Infinity;
    var maxY = -Infinity;

    var minX = Infinity;
    var minY = Infinity;

    var vertices = this.vertices;
    for (var i = 0, n = vertices.length; i < n; i += 2)
    {
        var rawX = vertices[i], rawY = vertices[i + 1];
        var x = (a * rawX) + (c * rawY) + tx;
        var y = (d * rawY) + (b * rawX) + ty;

        minX = x < minX ? x : minX;
        minY = y < minY ? y : minY;

        maxX = x > maxX ? x : maxX;
        maxY = y > maxY ? y : maxY;
    }

    if (minX === -Infinity || maxY === Infinity)
    {
        return core.math.Rectangle.EMPTY;
    }

    var bounds = this._bounds;

    bounds.x = minX;
    bounds.width = maxX - minX;

    bounds.y = minY;
    bounds.height = maxY - minY;

    // store a reference so that if this function gets called again in the render cycle we do not have to recalculate
    this._currentBounds = bounds;

    return bounds;
};

/**
 * Different drawing buffer modes supported
 *
 * @static
 * @constant
 * @property {object} DRAW_MODES
 * @property {number} DRAW_MODES.TRIANGLE_MESH
 * @property {number} DRAW_MODES.TRIANGLES
 */
Mesh.DRAW_MODES = {
    TRIANGLE_MESH: 0,
    TRIANGLES: 1
};