是否可以在一个立方体上放置两个图像？

Question

我正在尝试使用两个外部图像作为立方体的纹理。当我使用一个图像时，它可以完美工作并且渲染了我的多维数据集，但是在一个多维数据集上渲染两个图像时遇到了问题。一个是聚光灯的图像，中间有一个切口，因此可以从该孔中看到第二个图像。我得到的唯一警告是

WebGL警告：generateMipmap：Tex图像TEXTURE_2D级别0正在进行延迟初始化。

Answer 1

[当我尝试在Chrome 80中运行您的代码时，在JavaScript console中收到错误消息

第一个是这个

未捕获的TypeError：无法在'WebGLRenderingContext'上执行'texImage2D'：参数9的类型不是'ArrayBufferView'。在configureTexture1（js：148）

您正在尝试将HTMLImageElement传递给texImage2D，但唯一采用texImage2D的HTMLImageElement形式具有6个参数，而不是9。没有宽度，没有高度和边框参数。应该是

gl.texImage2D(
   gl.TEXTURE_2D,
   0,                // level
   gl.RGBA,          // internal format
   gl.RGBA,          // format
   gl.UNSIGNED_BYTE, // type
   someImageElement);

修复这两个错误会导致新的错误

警告：没有纹理绑定到单元1

当使用多个纹理时，需要将每个纹理分配给一个纹理单元。范例

// bind "someTexture" to texture unit 0
gl.activeTexture(gl.TEXTURE0 + 0);
gl.bindTexture(gl.TEXTURE_2D, someTexture);

// bind "otherTexture" to texture unit 1
gl.activeTexture(gl.TEXTURE0 + 1);
gl.bindTexture(gl.TEXTURE_2D, otherTexture);

var canvas;
var gl;

var numVertices  = 36;
var texSize = 64;

var image1 = document.getElementById("texImage1");
var image2 = document.getElementById("texImage2");

var program;

var texture1, texture2;

var pointsArray = [];
var colorsArray = [];
var texCoordsArray = [];


//texture coordinates
var texCoord = [
    vec2(0, 0),
    vec2(0, 1),
    vec2(1, 1),
    vec2(1, 0)
];

//cube dimensions
var vertices = [
    vec4( -0.5, -0.5,  0.5, 1.0 ),
    vec4( -0.5,  0.5,  0.5, 1.0 ),
    vec4( 0.5,  0.5,  0.5, 1.0 ),
    vec4( 0.5, -0.5,  0.5, 1.0 ),
    vec4( -0.5, -0.5, -0.5, 1.0 ),
    vec4( -0.5,  0.5, -0.5, 1.0 ),
    vec4( 0.5,  0.5, -0.5, 1.0 ),
    vec4( 0.5, -0.5, -0.5, 1.0 )
];

var vertexColors = [
    vec4( 0.0, 0.0, 0.0, 1.0 ),  
    vec4( 1.0, 0.0, 0.0, 1.0 ),  
    vec4( 1.0, 1.0, 0.0, 1.0 ),  
    vec4( 0.0, 1.0, 0.0, 1.0 ),  
    vec4( 0.0, 0.0, 1.0, 1.0 ),  
    vec4( 1.0, 0.0, 1.0, 1.0 ),  
    vec4( 0.0, 1.0, 1.0, 1.0 ),  
    vec4( 0.0, 1.0, 1.0, 1.0 )   
];

//rotation parameters
var xAxis = 0;
var yAxis = 1;
var zAxis = 2;
var axis = xAxis;

var theta = [45.0, 45.0, 45.0];

var thetaLoc;

function configureTexture1( image ) {
    texture1 = gl.createTexture();
    gl.activeTexture( gl.TEXTURE0 + 0 );
    gl.bindTexture( gl.TEXTURE_2D, texture1 );
    gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image1);
    gl.generateMipmap( gl.TEXTURE_2D );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER,gl.NEAREST_MIPMAP_LINEAR );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

    gl.uniform1i(gl.getUniformLocation( program, "texture1"), 0);
}


function configureTexture2( image ) {
    texture2 = gl.createTexture();
    gl.activeTexture( gl.TEXTURE0 + 1 );
    gl.bindTexture( gl.TEXTURE_2D, texture2 );
    gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image2);
    gl.generateMipmap( gl.TEXTURE_2D );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER,gl.NEAREST_MIPMAP_LINEAR );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

    gl.uniform1i(gl.getUniformLocation( program, "texture2"), 1);
}

function quad(a, b, c, d) {
     pointsArray.push(vertices[a]);
     colorsArray.push(vertexColors[a]);
     texCoordsArray.push(texCoord[0]);

     pointsArray.push(vertices[b]);
     colorsArray.push(vertexColors[a]);
     texCoordsArray.push(texCoord[1]);

     pointsArray.push(vertices[c]);
     colorsArray.push(vertexColors[a]);
     texCoordsArray.push(texCoord[2]);

     pointsArray.push(vertices[a]);
     colorsArray.push(vertexColors[a]);
     texCoordsArray.push(texCoord[0]);

     pointsArray.push(vertices[c]);
     colorsArray.push(vertexColors[a]);
     texCoordsArray.push(texCoord[2]);

     pointsArray.push(vertices[d]);
     colorsArray.push(vertexColors[a]);
     texCoordsArray.push(texCoord[3]);
}

function colorCube()
{
    quad( 1, 0, 3, 2 );
    quad( 2, 3, 7, 6 );
    quad( 3, 0, 4, 7 );
    quad( 6, 5, 1, 2 );
    quad( 4, 5, 6, 7 );
    quad( 5, 4, 0, 1 );
}


window.onload = function init() {

    canvas = document.getElementById( "gl-canvas" );

    gl = WebGLUtils.setupWebGL( canvas );
    if ( !gl ) { alert( "WebGL isn't available" ); }

    gl.viewport( 0, 0, canvas.width, canvas.height );
    gl.clearColor( 1.0, 1.0, 1.0, 1.0 );

    gl.enable(gl.DEPTH_TEST);

    program = initShaders( gl, "vertex-shader", "fragment-shader" );
    gl.useProgram( program );

    colorCube();


    //loading/initialising/binding buffers
    var cBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, cBuffer );
    gl.bufferData( gl.ARRAY_BUFFER, flatten(colorsArray), gl.STATIC_DRAW );

    var vColor = gl.getAttribLocation( program, "vColor" );
    gl.vertexAttribPointer( vColor, 4, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vColor );

    var vBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, vBuffer);
    gl.bufferData( gl.ARRAY_BUFFER, flatten(pointsArray), gl.STATIC_DRAW );

    var vPosition = gl.getAttribLocation( program, "vPosition" );
    gl.vertexAttribPointer( vPosition, 4, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vPosition );

    var tBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, tBuffer);
    gl.bufferData( gl.ARRAY_BUFFER, flatten(texCoordsArray), gl.STATIC_DRAW );

    var vTexCoord = gl.getAttribLocation( program, "vTexCoord" );
    gl.vertexAttribPointer( vTexCoord, 2, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vTexCoord );

    configureTexture1(image1);
    configureTexture2(image2);

    thetaLoc = gl.getUniformLocation(program, "theta");


 document.getElementById("ButtonX").onclick = function(){axis = xAxis;};
 document.getElementById("ButtonY").onclick = function(){axis = yAxis;};
 document.getElementById("ButtonZ").onclick = function(){axis = zAxis;};

    render();
}

var render = function() {
    gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
    theta[axis] += 2.0;
    gl.uniform3fv(thetaLoc, flatten(theta));
        
    gl.drawArrays( gl.TRIANGLES, 0, numVertices );
    requestAnimFrame(render);
}

<button id = "ButtonX">Rotate X</button>
<button id = "ButtonY">Rotate Y</button>
<button id = "ButtonZ">Rotate Z</button>

<script id="vertex-shader" type="x-shader/x-vertex">

attribute  vec4 vPosition;
attribute  vec4 vColor;
attribute  vec2 vTexCoord;

varying vec4 fColor;
varying vec2 fTexCoord;

uniform vec3 theta;

void main()
{

    vec3 angles = radians( theta );
    vec3 c = cos( angles );
    vec3 s = sin( angles );

    mat4 rx = mat4( 1.0,  0.0,  0.0, 0.0,
            0.0,  c.x,  s.x, 0.0,
            0.0, -s.x,  c.x, 0.0,
            0.0,  0.0,  0.0, 1.0 );

    mat4 ry = mat4( c.y, 0.0, -s.y, 0.0,
            0.0, 1.0,  0.0, 0.0,
            s.y, 0.0,  c.y, 0.0,
            0.0, 0.0,  0.0, 1.0 );


    mat4 rz = mat4( c.z, s.z, 0.0, 0.0,
            -s.z,  c.z, 0.0, 0.0,
            0.0,  0.0, 1.0, 0.0,
            0.0,  0.0, 0.0, 1.0 );

    fColor = vColor;
    fTexCoord = vTexCoord;
    gl_Position = rz * ry * rx * vPosition;

}
</script>

<script id="fragment-shader" type="x-shader/x-fragment">

precision mediump float;

varying vec4 fColor;
varying  vec2 fTexCoord;

uniform sampler2D texture1;
uniform sampler2D texture2;

void
main()
{
    gl_FragColor = fColor*(texture2D(texture1, fTexCoord)*texture2D(texture2, fTexCoord));

}
</script>

<script type="text/javascript"
src="https://esangel.github.io/WebGL/Common/webgl-utils.js"></script>
<script type="text/javascript" src="https://esangel.github.io/WebGL/Common/initShaders.js"></script>
<script type="text/javascript"
src="https://esangel.github.io/WebGL/Common/MV.js"></script>

<canvas id="gl-canvas" width="512" height="512">
Oops ... your browser doesn't support the HTML5 canvas element
</canvas>
<img id="texImage1" crossorigin=" " src = "https://i.imgur.com/ZKMnXce.png" crossOrigin="anonymous" hidden></img>
<img id="texImage2" crossorigin=" " src = "https://i.imgur.com/aqZRuFj.png" crossOrigin="anonymous" hidden></img>

我使用了这两个图像

一个F：https://i.imgur.com/ZKMnXce.png

白点：https://imgur.com/aqZRuFj

请注意，该代码未遵循正常的WebGL惯例。在初始化时，很多事情一次完成，只有在您绘制单件东西的情况下，这才起作用。

请参见this answer和/或this page和this one too