数组 – webgl drawElements:attribs设置不正确(重复n次)

所以,我已经开始了一个相当即时的视觉,三维编程世界之旅.我目前在webgl中具有相当强大的
javascript和大多数面向Web的语言背景,但这是我的第一个图形语言.

在尝试绘制我的第一个相当简单的形状时,我遇到了一个我无法找到解决方案的错误.它读取chrome作为:

WebGL:INVALID_OPERATION:drawElements:attribs设置不正确(重复n次)

其中n是一个看似随机变化的数字.有问题的代码在这里:

var tessVertexPositionBuffer;
var tessVertexColorBuffer;
var tessVertexIndexBuffer;
function initBuffers () {
    tessVertexPositionBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, tessVertexPositionBuffer);
    var vertices = [
    //innerfront
        -1.0, 1.0, 1.0,
        1.0, 1.0, 1.0,
        1.0, -1.0, 1.0,
        -1.0, -1.0, 1.0,
    //innerleft
        -1.0, 1.0, 1.0,
        -1.0, -1.0, 1.0,
        -1.0, 1.0, -1.0,
        -1.0, -1.0, -1.0,
    //innerback
        -1.0, 1.0, -1.0,
        1.0, 1.0, -1.0,
        -1.0, -1.0, -1.0,
        1.0, -1.0, -1.0,
    //innerright
        1.0, 1.0, 1.0,
        1.0, -1.0, 1.0,
        1.0, 1.0, -1.0,
        1.0, -1.0, -1.0,

    //topfront
        -1.0, 1.0, 1.0,
        1.0, 1.0, 1.0,
        -2.0, 2.0, 2.0,
        2.0, 2.0, 2.0,
    //topleft
        -1.0, 1.0, 1.0,
        -2.0, 2.0, 2.0,
        -1.0, 1.0, -1.0,
        -2.0, 2.0, -2.0,
    //topback
        -1.0, 1.0, -1.0,
        1.0, 1.0, -1.0,
        -2.0, 2.0, -2.0,
        2.0, 2.0, -2.0,         
    //topright
        1.0, 1.0, 1.0,
        2.0, 2.0, 2.0,
        1.0, 1.0, -1.0,
        2.0, 2.0, -2.0,


    //outerfront
        -2.0, 2.0, 2.0,
        2.0, 2.0, 2.0,
        -2.0, -2.0, 2.0,
        2.0, -2.0, 2.0,
    //outerleft
        -2.0, 2.0, 2.0,
        -2.0, -2.0, 2.0,
        -2.0, 2.0, -2.0,
        -2.0, -2.0, -2.0,           
    //outerback
        -2.0, 2.0, -2.0,
        2.0, 2.0, -2.0,
        -2.0, -2.0, -2.0,
        2.0, -2.0, -2.0,
    //outerright
        2.0, 2.0, 2.0,
        2.0, -2.0, 2.0,
        2.0, 2.0, -2.0,
        2.0, -2.0, -2.0,            

    //bottomfront       
        2.0, 2.0, 2.0,
        -2.0, 2.0, 2.0,
        -2.0, -2.0, 2.0,
        2.0, -2.0, 2.0,
    //bottomleft
        -1.0, -1.0, 1.0,
        -2.0, -2.0, 2.0,
        -1.0, -1.0, -1.0,
        -2.0, -2.0, -2.0,
    //bottomback
        -1.0, -1.0, -1.0,
        1.0, -1.0, -1.0,
        -2.0, -2.0, -2.0,
        2.0, -2.0, -2.0,
    //bottomright
        1.0, -1.0, 1.0,
        2.0, -2.0, 2.0,
        1.0, -1.0, -1.0,
        2.0, -2.0, -2.0
    ];
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
    tessVertexPositionBuffer.itemSize = 3;
    tessVertexPositionBuffer.numItems = 64;

    tessVertexColorBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, tessVertexColorBuffer);
    var colors = [
        [0.7, 0.7, 0.7, 1.0], //all inner sides
        [0.7, 0.7, 0.7, 1.0], 
        [0.7, 0.7, 0.7, 1.0], 
        [0.7, 0.7, 0.7, 1.0], 

        [0.7, 0.0, 0.7, 1.0], //all top sides
        [0.7, 0.0, 0.7, 1.0], 
        [0.7, 0.0, 0.7, 1.0], 
        [0.7, 0.0, 0.7, 1.0], 

        [0.7, 0.7, 0.0, 1.0], //all outer sides
        [0.7, 0.7, 0.0, 1.0], 
        [0.7, 0.7, 0.0, 1.0], 
        [0.7, 0.7, 0.0, 1.0], 

        [0.0, 0.7, 0.7, 1.0], //all bottom sides
        [0.0, 0.7, 0.7, 1.0],
        [0.0, 0.7, 0.7, 1.0],
        [0.0, 0.7, 0.7, 1.0],
    ];
    var unpackedColors = [];
    for (var i in colors) {
        var color = colors[i];
        for (var j=0; j< 4; j++) {
            unpackedColors = unpackedColors.concat(color);
        }   
    }

    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(unpackedColors), gl.STATIC_DRAW);
    tessVertexColorBuffer.itemSize = 4;
    tessVertexColorBuffer.numItems = 64;


    tessVertexIndexBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, tessVertexIndexBuffer);
    var tessVertexIndices = [
        0, 1, 2,  0, 2, 3,
        4, 5, 6,  5, 6, 7,
        8, 9, 10,  9, 10, 11,
        12, 13, 14,  13, 14, 15,
        16, 17, 18,  17, 18, 19,
        20, 21, 22,  21, 22, 23,
        24, 25, 26,  25, 26, 27,
        28, 29, 30,  29, 30, 31,
        32, 33, 34,  33, 34, 35,
        36, 37, 38,  37, 38, 39,
        40, 41, 42,  41, 42, 43,
        44, 45, 46,  45, 46, 47,
        48, 49, 50,  48, 50, 51,
        52, 53, 54,  53, 54, 55,
        56, 57, 58,  57, 58, 59,
        60, 61, 62,  61, 62, 63
    ];  
    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(tessVertexIndices), gl.STATIC_DRAW);
    tessVertexIndexBuffer.itemSize = 1;
    tessVertexIndexBuffer.numItems = 96;
}

并且缓冲区的实际绘图如下:

    gl.bindBuffer(gl.ARRAY_BUFFER, tessVertexPositionBuffer);
    gl.vertexAttribPointer(shaderProgram.vetexPositionAttribute, tessVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);

    gl.bindBuffer(gl.ARRAY_BUFFER, tessVertexColorBuffer);
    gl.vertexAttribPointer(shaderProgram.vertexColorAttribute, tessVertexColorBuffer.itemSize, gl.FLOAT, false, 0, 0);

    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, tessVertexIndexBuffer);
    setMatrixUniforms();
    gl.drawElements(gl.TRIANGLES, tessVertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0);

现在,这是相对逐字逐句来自learnwebgl,我只是想绘制一个简单的形状.我相对肯定我的问题在于我的缓冲区类型,因为我真的不太了解它们(我发现的大多数关于webGl的文献都是对语言或HYPERSUPERPRO类型的一般理解的新手).

我真的被卡住了.我已经多次检查了实际的顶点位置/颜色/索引,除非我已经熟悉了足够的代码,我对简单的错误视而不见,我在那里找不到错误.

我非常感谢你能在这个主题上发光的任何灯光.

最佳答案 看起来你的问题只是一个小错字. “实际绘制缓冲区”代码的第二行应该是:

gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, tessVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);

您错过了该行的vertexPositionAttribute中的第一个r.

我修改了第4课LearningWebGL教程以使用你的代码(使用固定的拼写错误),我有一个链接here.

如果您注意到有一个蓝色三角形,并且在空间中完全相同的位置绘制一个黄色三角形,这会导致一些闪烁.我不确定这是否是故意的.

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