Куб с двумя текстурами

Question

/**
 * A class creating buffers for a textured box to render it with WebGL
 */
class RasterTextureBox {
    /**
     * Creates all WebGL buffers for the textured box
     *     6 ------- 7
     *    / |       / |
     *   3 ------- 2  |
     *   |  |      |  |
     *   |  5 -----|- 4
     *   | /       | /
     *   0 ------- 1
     *  looking in negative z axis direction
     * @param {WebGLContext} gl - The canvas' context
     * @param {Vector} minPoint - The minimal x,y,z of the box
     * @param {Vector} maxPoint - The maximal x,y,z of the box
     */
    constructor(gl, minPoint, maxPoint, texture) {
        this.gl = gl;
        const mi = minPoint;
        const ma = maxPoint;
        let vertices = [
            // front
            mi.x, mi.y, ma.z, ma.x, mi.y, ma.z, ma.x, ma.y, ma.z,
            ma.x, ma.y, ma.z, mi.x, ma.y, ma.z, mi.x, mi.y, ma.z,
            // back
            ma.x, mi.y, mi.z, mi.x, mi.y, mi.z, mi.x, ma.y, mi.z,
            mi.x, ma.y, mi.z, ma.x, ma.y, mi.z, ma.x, mi.y, mi.z,
            // right
            ma.x, mi.y, ma.z, ma.x, mi.y, mi.z, ma.x, ma.y, mi.z,
            ma.x, ma.y, mi.z, ma.x, ma.y, ma.z, ma.x, mi.y, ma.z,
            // top
            mi.x, ma.y, ma.z, ma.x, ma.y, ma.z, ma.x, ma.y, mi.z,
            ma.x, ma.y, mi.z, mi.x, ma.y, mi.z, mi.x, ma.y, ma.z,
            // left
            mi.x, mi.y, mi.z, mi.x, mi.y, ma.z, mi.x, ma.y, ma.z,
            mi.x, ma.y, ma.z, mi.x, ma.y, mi.z, mi.x, mi.y, mi.z,
            // bottom
            mi.x, mi.y, mi.z, ma.x, mi.y, mi.z, ma.x, mi.y, ma.z,
            ma.x, mi.y, ma.z, mi.x, mi.y, ma.z, mi.x, mi.y, mi.z
        ];

        const vertexBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
        this.vertexBuffer = vertexBuffer;
        this.elements = vertices.length / 3;

        let cubeTexture = gl.createTexture();
        let cubeImage = new Image();
        cubeImage.onload = function () {
            gl.bindTexture(gl.TEXTURE_2D, cubeTexture);
            gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, cubeImage);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
            gl.bindTexture(gl.TEXTURE_2D, null);
        }
        cubeImage.src = texture;
        this.texBuffer = cubeTexture;

        let uv = [
            // front
            0, 0, 1, 0, 1, 1,
            1, 1, 0, 1, 0, 0,
            // back
            0, 0, 1, 0, 1, 1,
            1, 1, 0, 1, 0, 0,
            // right
            0, 0, 1, 0, 1, 1,
            1, 1, 0, 1, 0, 0,
            // top
            0, 0, 1, 0, 1, 1,
            1, 1, 0, 1, 0, 0,
            // left
            0, 0, 1, 0, 1, 1,
            1, 1, 0, 1, 0, 0,
            // bottom
            0, 0, 1, 0, 1, 1,
            1, 1, 0, 1, 0, 0,
        ];
        let uvBuffer = this.gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, uvBuffer);
        gl.bufferData(this.gl.ARRAY_BUFFER, new Float32Array(uv),
            gl.STATIC_DRAW);
        this.texCoords = uvBuffer;
    }

    /**
     * Renders the textured box
     * @param {Shader} shader - The shader used to render
     */
    render(shader) {
        this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.vertexBuffer);
        const positionLocation = shader.getAttributeLocation("a_position");
        this.gl.enableVertexAttribArray(positionLocation);
        this.gl.vertexAttribPointer(positionLocation, 3, this.gl.FLOAT, false, 0, 0);

        // Bind the texture coordinates in this.texCoords
        // to their attribute in the shader
        // TODO [exercise 9]
        this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.texCoords);
        const texCoordLocation = shader.getAttributeLocation("a_texCoord");
        this.gl.enableVertexAttribArray(texCoordLocation);
        this.gl.vertexAttribPointer(texCoordLocation, 2, this.gl.FLOAT, false, 0, 0);

        this.gl.activeTexture(gl.TEXTURE0);
        this.gl.bindTexture(gl.TEXTURE_2D, this.texBuffer);
        shader.getUniformInt("sampler").set(0);
        this.gl.drawArrays(this.gl.TRIANGLES, 0, this.elements);

        this.gl.disableVertexAttribArray(positionLocation);

        // TODO [exercise 9] disable texture vertex attrib array
        this.gl.disableVertexAttribArray(texCoordLocation);
    }
}

<script id="2d-fragment-shader" type="x-shader/x-fragment">
precision mediump float;

uniform sampler2D sampler;
varying vec2 v_texCoord;

void main( void ) {
  //gl_FragColor = vec4( 0.0, 0.0, 0.5, 1.0 );
  // Read fragment color from texture
  // TODO [exercise 9]
  gl_FragColor = texture2D(sampler, vec2(v_texCoord.s, v_texCoord.t));
}
</script>

<script id="2d-vertex-shader" type="x-shader/x-vertex">
attribute vec3 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;

uniform mat4 M;
uniform mat4 V;
uniform mat4 P;

void main(void)
{
    gl_Position = P * V * M * vec4( a_position, 1.0 );
    v_texCoord = a_texCoord;
}

Привет, я пытаюсь добавить две текстуры на мой куб (код сверху). Я могу объединить два изображения два одно, но я не знаю, как объединить мой куб с двумя изображениями. У моего куба уже есть одна текстура, я просто хочу добавить еще одну через конструктор. Ждем вашей помощи! Я благодарен за каждый совет или примеры кода!

<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>WebGL - 2 Textures</title>
    <link type="text/css" href="webgl-tutorials.css" rel="stylesheet" />
</head>
<body>
<canvas id="canvas"></canvas>
</body>
<!-- vertex shader -->
<script id="2d-vertex-shader" type="x-shader/x-vertex">
attribute vec2 a_position;
attribute vec2 a_texCoord;

uniform vec2 u_resolution;

varying vec2 v_texCoord;

void main() {
   // convert the rectangle from pixels to 0.0 to 1.0
   vec2 zeroToOne = a_position / u_resolution;

   // convert from 0->1 to 0->2
   vec2 zeroToTwo = zeroToOne * 2.0;

   // convert from 0->2 to -1->+1 (clipspace)
   vec2 clipSpace = zeroToTwo - 1.0;

   gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);

   // pass the texCoord to the fragment shader
   // The GPU will interpolate this value between points.
   v_texCoord = a_texCoord;
}
</script>
<!-- fragment shader -->
<script id="2d-fragment-shader" type="x-shader/x-fragment">
precision mediump float;

// our textures
uniform sampler2D u_image0;
uniform sampler2D u_image1;

// the texCoords passed in from the vertex shader.
varying vec2 v_texCoord;

void main() {
   vec4 color0 = texture2D(u_image0, v_texCoord);
   vec4 color1 = texture2D(u_image1, v_texCoord);
   gl_FragColor = color0 * color1;
}
</script>
<!--
for most samples webgl-utils only provides shader compiling/linking and
canvas resizing because why clutter the examples with code that's the same in every sample.
See http://webglfundamentals.org/webgl/lessons/webgl-boilerplate.html
and http://webglfundamentals.org/webgl/lessons/webgl-resizing-the-canvas.html
for webgl-utils, m3, m4, and webgl-lessons-ui.
-->
<script src="https://webgl2fundamentals.org/webgl/resources/webgl-utils.js"></script>
<script>
    "use strict";

    function loadImage(url, callback) {
        var image = new Image();
        image.src = url;
        image.onload = callback;
        return image;
    }

    function loadImages(urls, callback) {
        var images = [];
        var imagesToLoad = urls.length;

        // Called each time an image finished
        // loading.
        var onImageLoad = function() {
            --imagesToLoad;
            // If all the images are loaded call the callback.
            if (imagesToLoad == 0) {
                callback(images);
            }
        };

        for (var ii = 0; ii < imagesToLoad; ++ii) {
            var image = loadImage(urls[ii], onImageLoad);
            images.push(image);
        }
    }

    function main() {
        loadImages([
            "star.jpg",
            "normal.png",
        ], render);
    }

    function render(images) {
        // Get A WebGL context
        /** @type {HTMLCanvasElement} */
        var canvas = document.getElementById("canvas");
        var gl = canvas.getContext("webgl");
        if (!gl) {
            return;
        }

        // setup GLSL program
        var program = webglUtils.createProgramFromScripts(gl, ["2d-vertex-shader", "2d-fragment-shader"]);
        gl.useProgram(program);

        // look up where the vertex data needs to go.
        var positionLocation = gl.getAttribLocation(program, "a_position");
        var texcoordLocation = gl.getAttribLocation(program, "a_texCoord");

        // Create a buffer to put three 2d clip space points in
        var positionBuffer = gl.createBuffer();

        // Bind it to ARRAY_BUFFER (think of it as ARRAY_BUFFER = positionBuffer)
        gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
        // Set a rectangle the same size as the image.
        setRectangle(gl, 0, 0, images[0].width, images[0].height);

        // provide texture coordinates for the rectangle.
        var texcoordBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
            0.0,  0.0,
            1.0,  0.0,
            0.0,  1.0,
            0.0,  1.0,
            1.0,  0.0,
            1.0,  1.0,
        ]), gl.STATIC_DRAW);

        // create 2 textures
        var textures = [];
        for (var ii = 0; ii < 2; ++ii) {
            var texture = gl.createTexture();
            gl.bindTexture(gl.TEXTURE_2D, texture);

            // Set the parameters so we can render any size image.
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

            // Upload the image into the texture.
            gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, images[ii]);

            // add the texture to the array of textures.
            textures.push(texture);
        }

        // lookup uniforms
        var resolutionLocation = gl.getUniformLocation(program, "u_resolution");

        // lookup the sampler locations.
        var u_image0Location = gl.getUniformLocation(program, "u_image0");
        var u_image1Location = gl.getUniformLocation(program, "u_image1");

        webglUtils.resizeCanvasToDisplaySize(gl.canvas);

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

        // Clear the canvas
        gl.clearColor(0, 0, 0, 0);
        gl.clear(gl.COLOR_BUFFER_BIT);

        // Tell it to use our program (pair of shaders)
        gl.useProgram(program);

        // Turn on the position attribute
        gl.enableVertexAttribArray(positionLocation);

        // Bind the position buffer.
        gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);

        // Tell the position attribute how to get data out of positionBuffer (ARRAY_BUFFER)
        var size = 2;          // 2 components per iteration
        var type = gl.FLOAT;   // the data is 32bit floats
        var normalize = false; // don't normalize the data
        var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
        var offset = 0;        // start at the beginning of the buffer
        gl.vertexAttribPointer(
            positionLocation, size, type, normalize, stride, offset)

        // Turn on the teccord attribute
        gl.enableVertexAttribArray(texcoordLocation);

        // Bind the position buffer.
        gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);

        // Tell the position attribute how to get data out of positionBuffer (ARRAY_BUFFER)
        var size = 2;          // 2 components per iteration
        var type = gl.FLOAT;   // the data is 32bit floats
        var normalize = false; // don't normalize the data
        var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
        var offset = 0;        // start at the beginning of the buffer
        gl.vertexAttribPointer(
            texcoordLocation, size, type, normalize, stride, offset)

        // set the resolution
        gl.uniform2f(resolutionLocation, gl.canvas.width, gl.canvas.height);

        // set which texture units to render with.
        gl.uniform1i(u_image0Location, 0);  // texture unit 0
        gl.uniform1i(u_image1Location, 1);  // texture unit 1

        // Set each texture unit to use a particular texture.
        gl.activeTexture(gl.TEXTURE0);
        gl.bindTexture(gl.TEXTURE_2D, textures[0]);
        gl.activeTexture(gl.TEXTURE1);
        gl.bindTexture(gl.TEXTURE_2D, textures[1]);

        // Draw the rectangle.
        gl.drawArrays(gl.TRIANGLES, 0, 6);
    }

    function setRectangle(gl, x, y, width, height) {
        var x1 = x;
        var x2 = x + width;
        var y1 = y;
        var y2 = y + height;
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
            x1, y1,
            x2, y1,
            x1, y2,
            x1, y2,
            x2, y1,
            x2, y2,
        ]), gl.STATIC_DRAW);
    }

    main();
</script>
</html>

Answer 1

Если ваш код работает, вам нужно изменить фрагментный шейдер на использование двух текстур

<script id="2d-fragment-shader" type="x-shader/x-fragment">
precision mediump float;

uniform sampler2D sampler1;
uniform sampler2D sampler2;
varying vec2 v_texCoord;

void main( void ) {
  //gl_FragColor = vec4( 0.0, 0.0, 0.5, 1.0 );
  // Read fragment color from texture
  // TODO [exercise 9]
  gl_FragColor = texture2D(sampler1, vec2(v_texCoord.s, v_texCoord.t)) *
                 texture2D(sampler2, vec2(v_texCoord.s, v_texCoord.t));
}
</script>

И вам нужно, чтобы ваш JavaScript загружал 2 текстуры

 * @param {strings[]} textures An array of urls for textures
 */
constructor(gl, minPoint, maxPoint, textures) {

    this.texBuffers = textures.map((texture) => {
      const cubeTexture = gl.createTexture();
      const cubeImage = new Image();
      cubeImage.onload = function () {
        gl.bindTexture(gl.TEXTURE_2D, cubeTexture);
        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, cubeImage);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
        gl.bindTexture(gl.TEXTURE_2D, null);
      }
      cubeImage.src = texture;
      return cubeTexture;
    });

Затем в коде рендеринга вам нужно установить обе текстуры

    this.texBuffers.forEach((texBuffer, ndx) => {
      this.gl.activeTexture(gl.TEXTURE0 + ndx);
      this.gl.bindTexture(gl.TEXTURE_2D, texBuffer);
      shader.getUniformInt(`sampler${ndx}`).set(ndx);
    });

И вы бы назвали свой конструктор вот так

const rtBox = new RasterTextureBox(gl, minPoint, maxPoint, [
  "some/url/to/image1.png",
  "some/url/to/image2.png",
]);