Black Octopus Cartoons: [code]

<head>

canvas {

border: 2px solid black;

background-color: blue;

}

video {

display: none;

}

</style>

integrity="sha512-zhHQR0/H5SEBL3Wn6yYSaTTZej12z0hVZKOv3TwCUXT1z5qeqGcXJLLrbERYRScEDDpYIJhPC1fk31gqR783iQ=="

crossorigin="anonymous" defer>

</script>

</script>

var cubeRotation = 0.0;

window.onload = main;

function main() {

const canvas = document.querySelector('#box');

const gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');

if (!gl) {

alert('Unable to initialize WebGL. Your browser or machine may not support it.');

return;

}

/* Vertex shader program

const vsSource = `

attribute vec4 aVertexPosition;

attribute vec4 aVertexColor;

uniform mat4 uModelViewMatrix;

uniform mat4 uProjectionMatrix;

varying lowp vec4 vColor;

void main(void) {

gl_Position = uProjectionMatrix * uModelViewMatrix * aVertexPosition;

vColor = aVertexColor;

}

// Fragment shader program

const fsSource = `

varying lowp vec4 vColor;

void main(void) {

gl_FragColor = vColor;

}

// Initialize a shader program; this is where all the lighting

// for the vertices and so forth is established.

const shaderProgram = initShaderProgram(gl, vsSource, fsSource);

// Collect all the info needed to use the shader program.

// Look up which attributes our shader program is using

// for aVertexPosition, aVertexColor and also

// look up uniform locations.

const programInfo = {

program: shaderProgram,

attribLocations: {

vertexPosition: gl.getAttribLocation(shaderProgram, 'aVertexPosition'),

vertexColor: gl.getAttribLocation(shaderProgram, 'aVertexColor'),

uniformLocations: {

projectionMatrix: gl.getUniformLocation(shaderProgram, 'uProjectionMatrix'),

modelViewMatrix: gl.getUniformLocation(shaderProgram, 'uModelViewMatrix'),

}

};

// Here's where we call the routine that builds all the

// objects we'll be drawing.

const buffers = initBuffers(gl);

var then = 0;

// Draw the scene repeatedly

function render(now) {

now *= 0.001;  // convert to seconds

const deltaTime = now - then;

then = now;

drawScene(gl, programInfo, buffers, deltaTime);

requestAnimationFrame(render);

}

requestAnimationFrame(render);

}

// initBuffers

// Initialize the buffers we'll need. For this demo, we just

// have one object -- a simple three-dimensional cube.

function initBuffers(gl) {

// Create a buffer for the cube's vertex positions.

const positionBuffer = gl.createBuffer();

// Select the positionBuffer as the one to apply buffer

// operations to from here out.

gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);

// Now create an array of positions for the cube.

const positions = [

/* Box */

1,1,1,

-1,1,1,

-1,-1,1,

1,-1,1,

-1, -1, 1,

-1, -1, -1,

-1,1, -1,

-1, 1, 1,

1, 1, 1,

1, 1, -1,

1,  -1, -1,

1,  -1, 1,

1, -1, 1,

-1, -1, 1,

-1, -1, -1,

1, -1, -1,

-1, 1, -1,

1, 1, -1,

1, -1, -1,

-1, -1, -1,

1, 1, 1,

1, 3, 1,

-1, 3, 1,

-1, 1, 1,

];

// Now pass the list of positions into WebGL to build the

// shape. We do this by creating a Float32Array from the

// JavaScript array, then use it to fill the current buffer.

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

// Now set up the colors for the faces. We'll use solid colors

// for each face.

const faceColors = [

/* Box */

[1, 1, 1, 1.0],

[.9, .9, .9, 1.0],

[.8, .8, .8, 1.0],

[.7, .7, .7, 1.0],

[.6, .6, .6, 1.0],

[.8, .8, .8, 1.0],

];

// Convert the array of colors into a table for all the vertices.

var colors = [];

for (var j = 0; j < faceColors.length; ++j) {

const c = faceColors[j];

// Repeat each color four times for the four vertices of the face

colors = colors.concat(c, c, c, c);

}

const colorBuffer = gl.createBuffer();

gl.bindBuffer(gl.ARRAY_BUFFER, colorBuffer);

gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(colors), 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,    // back

8,  9,  10,     8,  10, 11,   // top

12, 13, 14,     12, 14, 15,   // bottom

16, 17, 18,     16, 18, 19,   // right

20, 21, 22,     20, 22, 23,

];

// Now send the element array to GL

gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,

new Uint16Array(indices), gl.STATIC_DRAW);

return {

position: positionBuffer,

color: colorBuffer,

indices: indexBuffer,

};

}

// Draw the scene.

function drawScene(gl, programInfo, buffers, deltaTime) {

gl.clearColor(0.1, 0.0, 0.1, 0.9);  // Clear to black, fully opaque

gl.clearDepth(1.0);                 // Clear everything

gl.enable(gl.DEPTH_TEST);           // Enable depth testing

gl.depthFunc(gl.LEQUAL);            // Near things obscure far things

// Clear the canvas before we start drawing on it.

gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

// Create a perspective matrix, a special matrix that is

// used to simulate the distortion of perspective in a camera.

// Our field of view is 45 degrees, with a width/height

// ratio that matches the display size of the canvas

// and we only want to see objects between 0.1 units

// and 100 units away from the camera.

const fieldOfView = 45 * Math.PI / 180;   // in radians

const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;

const zNear = 0.1;

const zFar = 100.0;

const projectionMatrix = mat4.create();

// note: glmatrix.js always has the first argument

// as the destination to receive the result.

mat4.perspective(projectionMatrix,

fieldOfView,

aspect,

zNear,

zFar);

// Set the drawing position to the "identity" point, which is

// the center of the scene.

const modelViewMatrix = mat4.create();

// Now move the drawing position a bit to where we want to

// start drawing the square.

mat4.translate(modelViewMatrix,     // destination matrix

modelViewMatrix,     // matrix to translate

[.5, 0, -15]);  // amount to translate

mat4.rotate(modelViewMatrix,  // destination matrix

modelViewMatrix,  // matrix to rotate

cubeRotation,     // amount to rotate in radians

[.5,1,.5]);       // axis to rotate around (Z)

mat4.rotate(modelViewMatrix,  // destination matrix

modelViewMatrix,  // matrix to rotate

cubeRotation * 1,// amount to rotate in radians

[1,1,0]);       // axis to rotate around (X)

// Tell WebGL how to pull out the positions from the position

// buffer into the vertexPosition attribute

{

const numComponents = 3;

const type = gl.FLOAT;

const normalize = false;

const stride = 0;

const offset = 0;

gl.bindBuffer(gl.ARRAY_BUFFER, buffers.position);

gl.vertexAttribPointer(

programInfo.attribLocations.vertexPosition,

numComponents,

type,

normalize,

stride,

offset);

gl.enableVertexAttribArray(

programInfo.attribLocations.vertexPosition);

}

// Tell WebGL how to pull out the colors from the color buffer

// into the vertexColor attribute.

{

const numComponents = 4;

const type = gl.FLOAT;

const normalize = false;

const stride = 0;

const offset = 0;

gl.bindBuffer(gl.ARRAY_BUFFER, buffers.color);

gl.vertexAttribPointer(

programInfo.attribLocations.vertexColor,

numComponents,

type,

normalize,

stride,

offset);

gl.enableVertexAttribArray(

programInfo.attribLocations.vertexColor);

}

// Tell WebGL which indices to use to index the vertices

gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffers.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 = 36;

const type = gl.UNSIGNED_SHORT;

const offset = 0;

gl.drawElements(gl.TRIANGLES, vertexCount, type, offset);

}

// Update the rotation for the next draw

cubeRotation += deltaTime;

}

// Initialize a shader program, so WebGL knows how to draw our data

function initShaderProgram(gl, vsSource, fsSource) {

const vertexShader = loadShader(gl, gl.VERTEX_SHADER, vsSource);

const fragmentShader = loadShader(gl, gl.FRAGMENT_SHADER, fsSource);

// Create the shader program

const shaderProgram = gl.createProgram();

gl.attachShader(shaderProgram, vertexShader);

gl.attachShader(shaderProgram, fragmentShader);

gl.linkProgram(shaderProgram);

// If creating the shader program failed, alert

if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {

alert('Unable to initialize the shader program: ' + gl.getProgramInfoLog(shaderProgram));

return null;

}

return shaderProgram;

}

// creates a shader of the given type, uploads the source and

// compiles it.

function loadShader(gl, type, source) {

const shader = gl.createShader(type);

// Send the source to the shader object

gl.shaderSource(shader, source);

// Compile the shader program

gl.compileShader(shader);

// See if it compiled successfully

if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {

alert('An error occurred compiling the shaders: ' + gl.getShaderInfoLog(shader));

gl.deleteShader(shader);

return null;
  }
  return shader;
}
</script>
  
  </div>

</body>
</html>
">

[code]_box