MinaGabriel · November 7, 2024 14:29
diff --git a/gistfile1.txt b/gistfile1.txt
 <!DOCTYPE html>
 <html lang="en">
 <head>
    <meta charset="utf-8"/>
    <title>Translate a Triangle</title>

 <body onload="main()">
 <canvas id="webgl" width="400" height="400">
    Please use a browser that supports "canvas"
 </canvas>
 </body>

 <script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/webgl-utils.js"></script>
 <script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/webgl-debug.js"></script>
 <script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/cuon-utils.js"></script>
 <script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/cuon-matrix.js"></script>
 <script type="text/javascript">

 // Rotation angle (degrees/second)
 var ANGLE_STEP = 45.0;


 // LookAtTrianglesWithKeys.js (c) 2012 matsuda
 // Vertex shader program
 var VSHADER_SOURCE =
  'attribute vec4 a_Position;\n' +
  'attribute vec4 a_Color;\n' +
  'uniform mat4 u_ViewMatrix;\n' +
  'uniform mat4 u_ModelMatrix;\n' +
  'uniform mat4 u_ProjMatrix;\n' +
  'varying vec4 v_Color;\n' +
  'void main() {\n' +
  '  gl_Position = u_ProjMatrix * u_ViewMatrix * u_ModelMatrix * a_Position;\n' +
  '  v_Color = a_Color;\n' +
  '}\n';

 // Fragment shader program
 var FSHADER_SOURCE =
  '#ifdef GL_ES\n' +
  'precision mediump float;\n' +
  '#endif\n' +
  'varying vec4 v_Color;\n' +
  'void main() {\n' +
  '  gl_FragColor = v_Color;\n' +
  '}\n';

 function main() {
  // Retrieve <canvas> element
  var canvas = document.getElementById('webgl');

  // Get the rendering context for WebGL
  var gl = getWebGLContext(canvas);
  if (!gl) {
    console.log('Failed to get the rendering context for WebGL');
    return;
  }

  // Initialize shaders
  if (!initShaders(gl, VSHADER_SOURCE, FSHADER_SOURCE)) {
    console.log('Failed to intialize shaders.');
    return;
  }

  // Set the vertex coordinates and color (the blue triangle is in the front)
  var n = initVertexBuffers(gl);
  if (n < 0) {
    console.log('Failed to set the vertex information');
    return;
  }

  // Specify the color for clearing <canvas>
  gl.clearColor(0, 0, 0, 1);

  // Get the storage location of u_ViewMatrix
  var u_ViewMatrix = gl.getUniformLocation(gl.program, 'u_ViewMatrix');
  if(!u_ViewMatrix) { 
    console.log('Failed to get the storage locations of u_ViewMatrix');
    return;
  }

  // Get storage location of u_ModelMatrix
  var u_ModelMatrix = gl.getUniformLocation(gl.program, 'u_ModelMatrix');
  if (!u_ModelMatrix) { 
    console.log('Failed to get the storage location of u_ModelMatrix');
    return;
  }

  // get the storage location of u_ProjMatrix
  var u_ProjMatrix = gl.getUniformLocation(gl.program, 'u_ProjMatrix');
  if (!u_ProjMatrix) { 
    console.log('Failed to get the storage location of u_ProjMatrix');
    return;
  }


  // Current rotation angle
  var currentAngle = 0.0;
  // rotation Model matrix
  var modelMatrix = new Matrix4();

  // Create the matrix to set the eye point, and the line of sight
  var projMatrix = new Matrix4();

  // Create the view matrix
  var viewMatrix = new Matrix4();
  // Register the event handler to be called on key press
  document.onkeydown = function(ev){ 
    keydown(ev, gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix); 
    console.log("keydown");
  };


  // Start drawing
  var tick = function() {
    currentAngle = animate(currentAngle);  // Update the rotation angle
    draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix);   // Draw the triangle
    requestAnimationFrame(tick, canvas); // Request that the browser calls tick
  };
  tick();

  //draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix);   // Draw
 }

 function initVertexBuffers(gl) {
  var verticesColors = new Float32Array([
    // Vertex coordinates and color
     0.0,  0.5,  -0.4,  0.4,  1.0,  0.4, // The back green one
    -0.5, -0.5,  -0.4,  0.4,  1.0,  0.4,
     0.5, -0.5,  -0.4,  1.0,  0.4,  0.4, 
   
  ]);
  var n = 3;

  // Create a buffer object
  var vertexColorbuffer = gl.createBuffer();  
  if (!vertexColorbuffer) {
    console.log('Failed to create the buffer object');
    return -1;
  }

  // Write the vertex information and enable it
  gl.bindBuffer(gl.ARRAY_BUFFER, vertexColorbuffer);
  gl.bufferData(gl.ARRAY_BUFFER, verticesColors, gl.STATIC_DRAW);

  var FSIZE = verticesColors.BYTES_PER_ELEMENT;
  //Get the storage location of a_Position, assign and enable buffer
  var a_Position = gl.getAttribLocation(gl.program, 'a_Position');
  if(a_Position < 0) {
    console.log('Failed to get the storage location of a_Position');
    return -1;
  }

  gl.vertexAttribPointer(a_Position, 3, gl.FLOAT, false, FSIZE * 6, 0);
  gl.enableVertexAttribArray(a_Position); 
   // Enable the assignment of the buffer object

  // Get the storage location of a_Position, assign buffer and enable
  var a_Color = gl.getAttribLocation(gl.program, 'a_Color');
  if(a_Color < 0) {
    console.log('Failed to get the storage location of a_Color');
    return -1;
  }
  // Assign the buffer object to a_Color variable
  gl.vertexAttribPointer(a_Color, 3, gl.FLOAT, false, FSIZE * 6, FSIZE * 3);
  gl.enableVertexAttribArray(a_Color);  
  // Enable the assignment of the buffer object

  return n;
 }

 var g_eyeX = 0.20, g_eyeY = 0.25, g_eyeZ = 0.25; // Eye position
 function keydown(ev, gl, n, u_ViewMatrix, viewMatrix,  currentAngle, modelMatrix, u_ModelMatrix,projMatrix, u_ProjMatrix) {
    if(ev.keyCode == 39) { // The right arrow key was pressed
      g_eyeX += 0.01;
    } else 
    if (ev.keyCode == 37) { // The left arrow key was pressed
      g_eyeX -= 0.01;
    } else { return; }
    draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix);    
 }

 function draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix) {

      // Specify the viewing volume
  projMatrix.setOrtho(-1.5, 1.5, -1.5, 1.0, 0, 1.5);

    // Pass the projection matrix to u_ProjMatrix
    gl.uniformMatrix4fv(u_ProjMatrix, false, projMatrix.elements);

    // Set the rotation matrix
  modelMatrix.setRotate(-currentAngle, 0, 0, 1); // Rotation angle, rotation axis (0, 0, 1)

  // Set the matrix to be used for to set the camera view
  viewMatrix.setLookAt(g_eyeX, g_eyeY, g_eyeZ, 0, 0, 0, 0, 1, 0);

  // Pass the view projection matrix
  gl.uniformMatrix4fv(u_ViewMatrix, false, viewMatrix.elements);
  // Pass the rotation matrix to the vertex shader
  gl.uniformMatrix4fv(u_ModelMatrix, false, modelMatrix.elements);

  gl.clear(gl.COLOR_BUFFER_BIT);     // Clear <canvas>

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

 // Last time that this function was called
 var g_last = Date.now();
 function animate(angle) {
  // Calculate the elapsed time
  var now = Date.now();
  var elapsed = now - g_last;
  g_last = now;
  // Update the current rotation angle (adjusted by the elapsed time)
  var newAngle = angle + (ANGLE_STEP * elapsed) / 1000.0;
  return newAngle %= 360;
 }

 </script>
 </head>
 </html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="utf-8"/>
	<title>Translate a Triangle</title>

	<body onload="main()">
	<canvas id="webgl" width="400" height="400">
	Please use a browser that supports "canvas"
	</canvas>
	</body>

	<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/webgl-utils.js"></script>
	<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/webgl-debug.js"></script>
	<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/cuon-utils.js"></script>
	<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/cuon-matrix.js"></script>
	<script type="text/javascript">

	// Rotation angle (degrees/second)
	var ANGLE_STEP = 45.0;


	// LookAtTrianglesWithKeys.js (c) 2012 matsuda
	// Vertex shader program
	var VSHADER_SOURCE =
	'attribute vec4 a_Position;\n' +
	'attribute vec4 a_Color;\n' +
	'uniform mat4 u_ViewMatrix;\n' +
	'uniform mat4 u_ModelMatrix;\n' +
	'uniform mat4 u_ProjMatrix;\n' +
	'varying vec4 v_Color;\n' +
	'void main() {\n' +
	' gl_Position = u_ProjMatrix * u_ViewMatrix * u_ModelMatrix * a_Position;\n' +
	' v_Color = a_Color;\n' +
	'}\n';

	// Fragment shader program
	var FSHADER_SOURCE =
	'#ifdef GL_ES\n' +
	'precision mediump float;\n' +
	'#endif\n' +
	'varying vec4 v_Color;\n' +
	'void main() {\n' +
	' gl_FragColor = v_Color;\n' +
	'}\n';

	function main() {
	// Retrieve <canvas> element
	var canvas = document.getElementById('webgl');

	// Get the rendering context for WebGL
	var gl = getWebGLContext(canvas);
	if (!gl) {
	console.log('Failed to get the rendering context for WebGL');
	return;
	}

	// Initialize shaders
	if (!initShaders(gl, VSHADER_SOURCE, FSHADER_SOURCE)) {
	console.log('Failed to intialize shaders.');
	return;
	}

	// Set the vertex coordinates and color (the blue triangle is in the front)
	var n = initVertexBuffers(gl);
	if (n < 0) {
	console.log('Failed to set the vertex information');
	return;
	}

	// Specify the color for clearing <canvas>
	gl.clearColor(0, 0, 0, 1);

	// Get the storage location of u_ViewMatrix
	var u_ViewMatrix = gl.getUniformLocation(gl.program, 'u_ViewMatrix');
	if(!u_ViewMatrix) {
	console.log('Failed to get the storage locations of u_ViewMatrix');
	return;
	}

	// Get storage location of u_ModelMatrix
	var u_ModelMatrix = gl.getUniformLocation(gl.program, 'u_ModelMatrix');
	if (!u_ModelMatrix) {
	console.log('Failed to get the storage location of u_ModelMatrix');
	return;
	}

	// get the storage location of u_ProjMatrix
	var u_ProjMatrix = gl.getUniformLocation(gl.program, 'u_ProjMatrix');
	if (!u_ProjMatrix) {
	console.log('Failed to get the storage location of u_ProjMatrix');
	return;
	}


	// Current rotation angle
	var currentAngle = 0.0;
	// rotation Model matrix
	var modelMatrix = new Matrix4();

	// Create the matrix to set the eye point, and the line of sight
	var projMatrix = new Matrix4();

	// Create the view matrix
	var viewMatrix = new Matrix4();
	// Register the event handler to be called on key press
	document.onkeydown = function(ev){
	keydown(ev, gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix);
	console.log("keydown");
	};


	// Start drawing
	var tick = function() {
	currentAngle = animate(currentAngle); // Update the rotation angle
	draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix); // Draw the triangle
	requestAnimationFrame(tick, canvas); // Request that the browser calls tick
	};
	tick();

	//draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix); // Draw
	}

	function initVertexBuffers(gl) {
	var verticesColors = new Float32Array([
	// Vertex coordinates and color
	0.0, 0.5, -0.4, 0.4, 1.0, 0.4, // The back green one
	-0.5, -0.5, -0.4, 0.4, 1.0, 0.4,
	0.5, -0.5, -0.4, 1.0, 0.4, 0.4,

	]);
	var n = 3;

	// Create a buffer object
	var vertexColorbuffer = gl.createBuffer();
	if (!vertexColorbuffer) {
	console.log('Failed to create the buffer object');
	return -1;
	}

	// Write the vertex information and enable it
	gl.bindBuffer(gl.ARRAY_BUFFER, vertexColorbuffer);
	gl.bufferData(gl.ARRAY_BUFFER, verticesColors, gl.STATIC_DRAW);

	var FSIZE = verticesColors.BYTES_PER_ELEMENT;
	//Get the storage location of a_Position, assign and enable buffer
	var a_Position = gl.getAttribLocation(gl.program, 'a_Position');
	if(a_Position < 0) {
	console.log('Failed to get the storage location of a_Position');
	return -1;
	}

	gl.vertexAttribPointer(a_Position, 3, gl.FLOAT, false, FSIZE * 6, 0);
	gl.enableVertexAttribArray(a_Position);
	// Enable the assignment of the buffer object

	// Get the storage location of a_Position, assign buffer and enable
	var a_Color = gl.getAttribLocation(gl.program, 'a_Color');
	if(a_Color < 0) {
	console.log('Failed to get the storage location of a_Color');
	return -1;
	}
	// Assign the buffer object to a_Color variable
	gl.vertexAttribPointer(a_Color, 3, gl.FLOAT, false, FSIZE * 6, FSIZE * 3);
	gl.enableVertexAttribArray(a_Color);
	// Enable the assignment of the buffer object

	return n;
	}

	var g_eyeX = 0.20, g_eyeY = 0.25, g_eyeZ = 0.25; // Eye position
	function keydown(ev, gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix,projMatrix, u_ProjMatrix) {
	if(ev.keyCode == 39) { // The right arrow key was pressed
	g_eyeX += 0.01;
	} else
	if (ev.keyCode == 37) { // The left arrow key was pressed
	g_eyeX -= 0.01;
	} else { return; }
	draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix);
	}

	function draw(gl, n, u_ViewMatrix, viewMatrix, currentAngle, modelMatrix, u_ModelMatrix, projMatrix, u_ProjMatrix) {

	// Specify the viewing volume
	projMatrix.setOrtho(-1.5, 1.5, -1.5, 1.0, 0, 1.5);

	// Pass the projection matrix to u_ProjMatrix
	gl.uniformMatrix4fv(u_ProjMatrix, false, projMatrix.elements);

	// Set the rotation matrix
	modelMatrix.setRotate(-currentAngle, 0, 0, 1); // Rotation angle, rotation axis (0, 0, 1)

	// Set the matrix to be used for to set the camera view
	viewMatrix.setLookAt(g_eyeX, g_eyeY, g_eyeZ, 0, 0, 0, 0, 1, 0);

	// Pass the view projection matrix
	gl.uniformMatrix4fv(u_ViewMatrix, false, viewMatrix.elements);
	// Pass the rotation matrix to the vertex shader
	gl.uniformMatrix4fv(u_ModelMatrix, false, modelMatrix.elements);

	gl.clear(gl.COLOR_BUFFER_BIT); // Clear <canvas>

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

	// Last time that this function was called
	var g_last = Date.now();
	function animate(angle) {
	// Calculate the elapsed time
	var now = Date.now();
	var elapsed = now - g_last;
	g_last = now;
	// Update the current rotation angle (adjusted by the elapsed time)
	var newAngle = angle + (ANGLE_STEP * elapsed) / 1000.0;
	return newAngle %= 360;
	}

	</script>
	</head>
	</html>