jeans.js

/// <reference path="webgl.d.ts" />

let jeans = class {
    constructor(gl, pos) {
        this.positionBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, this.positionBuffer);

        this.positions = [
             // Front face
             -0.2, 0.0, 0.0,
             -0.05, 0.0, 0.0,
             -0.05, 0.4, 0.0,
             -0.2, 0.4, 0.0,
             //Back Face
            -0.05, 0.0, 0.0,
            -0.05, 0.0, -0.2,
            -0.05, 0.4, -0.2,
            -0.05, 0.4, 0.0,
             //Top Face
            -0.2, 0.0, 0.0,
            -0.2, 0.0, -0.2,
            -0.2, 0.4, -0.2,
            -0.2, 0.4, 0.0,
            //Top Face
            -0.2, 0.4, 0.0,
            -0.05, 0.4, 0.0,
            -0.05, 0.4, -0.2,
            -0.2, 0.4, -0.2,

             // Front face
             0.2, 0.0, 0.0,
             0.05, 0.0, 0.0,
             0.05, 0.4, 0.0,
             0.2, 0.4, 0.0,
             //Back Face
             0.05, 0.0, 0.0,
             0.05, 0.0, -0.2,
             0.05, 0.4, -0.2,
             0.05, 0.4, 0.0,
             //Top Face
             0.2, 0.0, 0.0,
             0.2, 0.0, -0.2,
             0.2, 0.4, -0.2,
             0.2, 0.4, 0.0,
             //Top Face
             0.2, 0.4, 0.0,
             0.05, 0.4, 0.0,
             0.05, 0.4, -0.2,
             0.2, 0.4, -0.2,
        ];

        this.rotation = 0;

        this.pos = pos;

        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(this.positions), gl.STATIC_DRAW);
        
        const textureCoordBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, textureCoordBuffer);

  const textureCoordinates = [
    // Front
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Back
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Top
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Front
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Back
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Top
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Back
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
    // Top
    0.0,  0.0,
    1.0,  0.0,
    1.0,  1.0,
    0.0,  1.0,
  ];

  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoordinates),
                gl.STATIC_DRAW);

        // Build the element array buffer; this specifies the indices
        // into the vertex arrays for each face's vertices.

        const indexBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);

        // This array defines each face as two triangles, using the
        // indices into the vertex array to specify each triangle's
        // position.

        const indices = [
            0, 1, 2,    0, 2, 3, // front
            4, 5, 6,    4, 6, 7,
            8, 9, 10,   8, 10, 11,
            12, 13, 14,  12, 14, 15,
            16, 17, 18,  16, 18, 19,
            20, 21, 22,  20, 22, 23,
            24, 25, 26,  24, 26, 27,
            28, 29, 30,  28, 30, 31,
        ];

        // Now send the element array to GL

        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,
            new Uint16Array(indices), gl.STATIC_DRAW);

        this.buffer = {
            position: this.positionBuffer,
             textureCoord: textureCoordBuffer,
            indices: indexBuffer,
        }

    }

    drawjeans(gl, projectionMatrix, programInfo, deltaTime, texture) {
        const modelViewMatrix = mat4.create();
        mat4.translate(
            modelViewMatrix,
            modelViewMatrix,
            this.pos
        );
        
        //this.rotation += Math.PI / (((Math.random()) % 100) + 50);

        mat4.rotate(modelViewMatrix,
            modelViewMatrix,
            this.rotation,
            [1, 1, 1]);

        {
            const numComponents = 3;
            const type = gl.FLOAT;
            const normalize = false;
            const stride = 0;
            const offset = 0;
            gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer.position);
            gl.vertexAttribPointer(
                programInfo.attribLocations.vertexPosition,
                numComponents,
                type,
                normalize,
                stride,
                offset);
            gl.enableVertexAttribArray(
                programInfo.attribLocations.vertexPosition);
        }

        // tell webgl how to pull out the texture coordinates from buffer
		{
		    const num = 2; // every coordinate composed of 2 values
		    const type = gl.FLOAT; // the data in the buffer is 32 bit float
		    const normalize = false; // don't normalize
		    const stride = 0; // how many bytes to get from one set to the next
		    const offset = 0; // how many bytes inside the buffer to start from
		    gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer.textureCoord);
		    gl.vertexAttribPointer(programInfo.attribLocations.textureCoord, num, type, normalize, stride, offset);
		    gl.enableVertexAttribArray(programInfo.attribLocations.textureCoord);
		}

		  // Tell WebGL we want to affect texture unit 0
		  gl.activeTexture(gl.TEXTURE0);
		
		  // Bind the texture to texture unit 0
		  gl.bindTexture(gl.TEXTURE_2D, texture);
		
		  // Tell the shader we bound the texture to texture unit 0
		  gl.uniform1i(programInfo.uniformLocations.uSampler, 0);

        // Tell WebGL which indices to use to index the vertices
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.buffer.indices);

        // Tell WebGL to use our program when drawing

        gl.useProgram(programInfo.program);

        // Set the shader uniforms

        gl.uniformMatrix4fv(
            programInfo.uniformLocations.projectionMatrix,
            false,
            projectionMatrix);
        gl.uniformMatrix4fv(
            programInfo.uniformLocations.modelViewMatrix,
            false,
            modelViewMatrix);

        {
            const vertexCount = 48;
            const type = gl.UNSIGNED_SHORT;
            const offset = 0;
            gl.drawElements(gl.TRIANGLES, vertexCount, type, offset);
        }

    }
};

//
// Initialize a texture and load an image.
// When the image finished loading copy it into the texture.
//
function loadTexture(gl, url) {
  const texture = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, texture);

  // Because images have to be download over the internet
  // they might take a moment until they are ready.
  // Until then put a single pixel in the texture so we can
  // use it immediately. When the image has finished downloading
  // we'll update the texture with the contents of the image.
  const level = 0;
  const internalFormat = gl.RGBA;
  const width = 1;
  const height = 1;
  const border = 0;
  const srcFormat = gl.RGBA;
  const srcType = gl.UNSIGNED_BYTE;
  const pixel = new Uint8Array([0, 0, 255, 255]);  // opaque blue
  gl.texImage2D(gl.TEXTURE_2D, level, internalFormat,
                width, height, border, srcFormat, srcType,
                pixel);

  const image = new Image();
  image.onload = function() {
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texImage2D(gl.TEXTURE_2D, level, internalFormat,
                  srcFormat, srcType, image);

    // WebGL1 has different requirements for power of 2 images
    // vs non power of 2 images so check if the image is a
    // power of 2 in both dimensions.
    if (isPowerOf2(image.width) && isPowerOf2(image.height)) {
       // Yes, it's a power of 2. Generate mips.
       gl.generateMipmap(gl.TEXTURE_2D);
    } else {
       // No, it's not a power of 2. Turn off mips and set
       // wrapping to clamp to edge
       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.LINEAR);
    }
  };
  image.src = url;

  return texture;
}

function isPowerOf2(value) {
  return (value & (value - 1)) == 0;
}