三维中的精灵动画变得像素化

Question

我尝试使用超过30帧的精灵表格来制作纹理动画。然而，即使我能够完美地执行所需的动画，如果帧超过30，输出也会变得像素化。请告诉我为什么会发生这种情况。

下面提到的例子： http://stemkoski.github.com/Three.js/Texture-Animation.html

function TextureAnimator(texture, tilesHoriz, tilesVert, numTiles, tileDispDuration) 
{   
    // note: texture passed by reference, will be updated by the update function.

    this.tilesHorizontal = tilesHoriz;
    this.tilesVertical = tilesVert;

    // how many images does this spritesheet contain?
    //  usually equals tilesHoriz * tilesVert, but not necessarily,
    //  if there at blank tiles at the bottom of the spritesheet. 
    this.numberOfTiles = numTiles;
    texture.wrapS = texture.wrapT = THREE.RepeatWrapping; 
    texture.repeat.set( 1 / this.tilesHorizontal, 1 / this.tilesVertical );

    // how long should each image be displayed?
    this.tileDisplayDuration = tileDispDuration;

    // how long has the current image been displayed?
    this.currentDisplayTime = 0;

    // which image is currently being displayed?
    this.currentTile = 0;

    this.update = function( milliSec )
    {
        this.currentDisplayTime += milliSec;
        while (this.currentDisplayTime > this.tileDisplayDuration)
        {
            this.currentDisplayTime -= this.tileDisplayDuration;
            this.currentTile++;
            if (this.currentTile == this.numberOfTiles)
                this.currentTile = 0;
            var currentColumn = this.currentTile % this.tilesHorizontal;
            texture.offset.x = currentColumn / this.tilesHorizontal;
            var currentRow = Math.floor( this.currentTile / this.tilesHorizontal );
            texture.offset.y = currentRow / this.tilesVertical;
        }
    };
}       

超过25帧的纹理变得像素化

var runnerTexture = new THREE.ImageUtils.loadTexture( 'images/run.png' );
// a texture with 10 frames arranged horizontally, display each for 75 millisec
annie = new TextureAnimator( runnerTexture, 10, 1, 10, 75 ); 
var runnerMaterial = new THREE.MeshBasicMaterial( { map: runnerTexture } );