This tutorial is not going to introduce anything earth-shattering. We just need to start doing a little bit of housekeeping.
I am sure you may be noticing now that the tutorial sample application has been growing quite a bit over the last few tutorials, and this starts making the code a little bit unwieldy.
The first thing I have done is to move all the Javascript for O3D completely out of the HTML page, and put it all into it’s own JS file. I won’t talk much more about that here, as that is a rather standard practice.
I am, however, more interested in the shaders. Up to now, all the shaders needed on the page have been stored in a textarea and then loaded into the effect when needed (which in our case was the initialisation function). Now, the problems with doing it this way is that it does not make it very easy to reuse the effect between multiple pages, and it also makes the HTML page substantially bigger and therefore harder to work with.
So what we need to do is move all the shader code into an external file, which in this tutorial, I have put into shaders/solidred.shader. This is simply a text file containing what used to be in the effects div.
Within the O3D code, the only change that needs to be done to load the shader is in the initialisation function where we load the shader, we need to a different function to load the shader from the external file into the effect, which is done with this code.
var redEffect = g_pack.createObject('Effect');
var shaderString = 'shaders/solidred.shader';
o3djs.effect.loadEffect(redEffect, shaderString);
The full listing of the tutorial is now in three files, so here they are:
tutorial7.html
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Tutorial 7: Moving the javascript and shaders out of the HTML
</title>
<script type="text/javascript" src="o3djs/base.js"></script>
<script type="text/javascript" src="tutorial7/tutorial7.js"></script>
</head>
<body>
<h1>Tutorial 7: Moving the Javascript and shaders out of the HTML</h1>
The Javascript and the shaders in this tutorial are now loaded from
external files rather than in the HTML
<br/>
<div id="o3d" style="width: 300px; height: 300px;"></div>
</body>
</html>
tutorial7.js
o3djs.require('o3djs.util');
o3djs.require('o3djs.math');
o3djs.require('o3djs.rendergraph');
o3djs.require('o3djs.canvas');
o3djs.require('o3djs.quaternions');
o3djs.require('o3djs.event');
o3djs.require('o3djs.arcball');
// Events
// Run the init() function once the page has finished loading.
// Run the uninit() function when the page has is unloaded.
window.onload = init;
window.onunload = uninit;
// global variables
var g_o3dElement;
var g_o3d;
var g_math;
var g_client;
var g_pack;
var g_clock = 0;
var g_timeMult = 1;
var g_cubeTransform;
var g_textCanvas;
var g_paint;
var g_canvasLib;
var g_3dRoot;
var g_hudRoot;
var g_viewInfo;
var g_hudViewInfo;
var g_keyPressDelta = 0.05;
var g_quaternions;
var g_aball;
var g_thisRot;
var g_lastRot;
var g_dragging = false;
var g_camera = {
eye: [0, 0, 5],
target: [0, 0, 0]
};
function startDragging(e) {
g_lastRot = g_thisRot;
g_aball.click([e.x, e.y]);
g_dragging = true;
}
function drag(e) {
if (g_dragging) {
var rotationQuat = g_aball.drag([e.x, e.y]);
var rot_mat = g_quaternions.quaternionToRotation(rotationQuat);
g_thisRot = g_math.matrix4.mul(g_lastRot, rot_mat);
var m = g_3dRoot.localMatrix;
g_math.matrix4.setUpper3x3(m, g_thisRot);
g_3dRoot.localMatrix = m;
}
}
function stopDragging(e) {
g_dragging = false;
}
function scrollMe(e) {
if (e.deltaY) {
g_camera.eye =
g_math.mulScalarVector((e.deltaY < 0 ? 11 : 13) / 12, g_camera.eye);
g_viewInfo.drawContext.view = g_math.matrix4.lookAt(g_camera.eye,
g_camera.target,
[0, 1, 0]);
}
}
function createCube(material) {
var cubeShape = g_pack.createObject('Shape');
var cubePrimitive = g_pack.createObject('Primitive');
var streamBank = g_pack.createObject('StreamBank');
cubePrimitive.material = material;
cubePrimitive.owner = cubeShape;
cubePrimitive.streamBank = streamBank;
cubePrimitive.primitiveType = g_o3d.Primitive.TRIANGLELIST;
cubePrimitive.numberPrimitives = 12; // 12 triangles
cubePrimitive.numberVertices = 8; // 8 vertices in total
var positionArray = [
-0.5, -0.5, 0.5, // vertex 0
0.5, -0.5, 0.5, // vertex 1
-0.5, 0.5, 0.5, // vertex 2
0.5, 0.5, 0.5, // vertex 3
-0.5, 0.5, -0.5, // vertex 4
0.5, 0.5, -0.5, // vertex 5
-0.5, -0.5, -0.5, // vertex 6
0.5, -0.5, -0.5 // vertex 7
];
var indicesArray = [
0, 1, 2, // face 1
2, 1, 3,
2, 3, 4, // face 2
4, 3, 5,
4, 5, 6, // face 3
6, 5, 7,
6, 7, 0, // face 4
0, 7, 1,
1, 7, 3, // face 5
3, 7, 5,
6, 0, 4, // face 6
4, 0, 2
];
var positionsBuffer = g_pack.createObject('VertexBuffer');
var positionsField = positionsBuffer.createField('FloatField', 3);
positionsBuffer.set(positionArray);
var indexBuffer = g_pack.createObject('IndexBuffer');
indexBuffer.set(indicesArray);
streamBank.setVertexStream(
g_o3d.Stream.POSITION, // This stream stores vertex positions
0, // First (and only) position stream
positionsField, // field: the field this stream uses.
0); // start_index
// Associate the triangle indices Buffer with the primitive.
cubePrimitive.indexBuffer = indexBuffer;
return cubeShape;
}
function drawText(str) {
// Clear to completely transparent.
g_textCanvas.canvas.clear([0.5, 0.5, 0.5, 0.5]);
// Reuse the global paint object
var paint = g_paint;
paint.color = [1, 1, 1, 1];
paint.textSize = 12;
paint.textTypeface = 'Comic Sans MS';
paint.textAlign = g_o3d.CanvasPaint.LEFT;
paint.shader = null;
g_textCanvas.canvas.drawText(str, 10, 30, paint);
g_textCanvas.updateTexture();
}
/**
* This method gets called every time O3D renders a frame. Here's
* where we update the cube's transform to make it spin.
* @param {o3d.RenderEvent} renderEvent The render event object that
* gives us the elapsed time since the last time a frame was rendered.
*/
function renderCallback(renderEvent) {
g_clock += renderEvent.elapsedTime * g_timeMult;
drawText("Hello world - " + (Math.round(g_clock * 100) / 100) + "s");
}
/**
* Function performing the rotate action in response to a key-press.
* Rotates the scene based on key pressed. (w ,s, a, d). Note that the
* x,y-axis referenced here are relative to the current view of scene.
* @param {keyPressed} The letter pressed, in lower case.
* @param {delta} The angle by which the scene should be rotated.
* @return true if an action was taken.
*/
function keyPressedAction(keyPressed, delta) {
var actionTaken = false;
switch(keyPressed) {
case 'a':
g_3dRoot.localMatrix =
g_math.matrix4.mul(g_3dRoot.localMatrix,
g_math.matrix4.rotationY(-delta));
actionTaken = true;
break;
case 'd':
g_3dRoot.localMatrix =
g_math.matrix4.mul(g_3dRoot.localMatrix,
g_math.matrix4.rotationY(delta));
actionTaken = true;
break;
case 'w':
g_3dRoot.localMatrix =
g_math.matrix4.mul(g_3dRoot.localMatrix,
g_math.matrix4.rotationX(-delta));
actionTaken = true;
break;
case 's':
g_3dRoot.localMatrix =
g_math.matrix4.mul(g_3dRoot.localMatrix,
g_math.matrix4.rotationX(delta));
actionTaken = true;
break;
}
return actionTaken;
}
/**
* Callback for the keypress event.
* Invokes the action to be performed for the key pressed.
* @param {event} keyPress event passed to us by javascript.
*/
function keyPressedCallback(event) {
event = event || window.event;
// Ignore accelerator key messages.
if (event.metaKey)
return;
var keyChar =String.fromCharCode(o3djs.event.getEventKeyChar(event));
// Just in case they have capslock on.
keyChar = keyChar.toLowerCase();
if (keyPressedAction(keyChar, g_keyPressDelta)) {
o3djs.event.cancel(event);
}
}
/**
* Creates the client area.
*/
function init() {
o3djs.util.makeClients(initStep2);
}
/**
* Initializes O3D.
* @param {Array} clientElements Array of o3d object elements.
*/
function initStep2(clientElements) {
// Initializes global variables and libraries.
g_o3dElement = clientElements[0];
g_client = g_o3dElement.client;
g_o3d = g_o3dElement.o3d;
g_math = o3djs.math;
g_quaternions = o3djs.quaternions;
// Initialize O3D sample libraries.
o3djs.base.init(g_o3dElement);
// Create a pack to manage the objects created.
g_pack = g_client.createPack();
//Create the arcball which is used for the rotation
g_aball = o3djs.arcball.create(300, 300);
//Initialise rotation matrixes
g_lastRot = g_math.matrix4.identity();
g_thisRot = g_math.matrix4.identity();
// Create 2 root transforms, one for the 3d parts and 2d parts.
// This is not strictly neccassary but it is helpful.
g_3dRoot = g_pack.createObject('Transform');
g_hudRoot = g_pack.createObject('Transform');
// Create the render graph for a view.
g_viewInfo = o3djs.rendergraph.createBasicView(
g_pack,
g_3dRoot,
g_client.renderGraphRoot);
// Set the background color to black.
g_viewInfo.clearBuffer.clearColor = [0, 0, 0, 1];
// Create a second view for the hud.
g_hudViewInfo = o3djs.rendergraph.createBasicView(
g_pack,
g_hudRoot,
g_client.renderGraphRoot);
// Make sure the hud gets drawn after the 3d stuff
g_hudViewInfo.root.priority = g_viewInfo.root.priority + 1;
// Turn off clearing the color for the hud since that would erase the
// 3d parts but leave clearing the depth and stencil so the HUD is
// unaffected by anything done by the 3d parts.
g_hudViewInfo.clearBuffer.clearColorFlag = false;
// Set up a perspective view
g_viewInfo.drawContext.projection = g_math.matrix4.perspective(
g_math.degToRad(30), // 30 degree fov.
g_client.width / g_client.height,
1, // Near plane.
5000); // Far plane.
// Set up our view transformation to look towards the world origin
// where the cube is located.
g_viewInfo.drawContext.view = g_math.matrix4.lookAt(g_camera.eye, //eye
g_camera.target, // target
[0, 1, 0]); // up
//Set up the 2d orthographic view
g_hudViewInfo.drawContext.projection = g_math.matrix4.orthographic(
0 + 0.5,
g_client.width + 0.5,
g_client.height + 0.5,
0 + 0.5,
0.001,
1000);
g_hudViewInfo.drawContext.view = g_math.matrix4.lookAt(
[0, 0, 1], // eye
[0, 0, 0], // target
[0, 1, 0]); // up
// Create an Effect object and initialize it using the shaders
// from the text area.
// Load effect
var redEffect = g_pack.createObject('Effect');
var shaderString = 'shaders/solidred.shader';
o3djs.effect.loadEffect(redEffect, shaderString);
// Create a Material for the mesh.
var redMaterial = g_pack.createObject('Material');
// Set the material's drawList.
redMaterial.drawList = g_viewInfo.performanceDrawList;
// Apply our effect to this material. The effect tells the 3D
// hardware which shaders to use.
redMaterial.effect = redEffect;
// Create the Shape for the cube mesh and assign its material.
var cubeShape = createCube(redMaterial);
// Create a new transform and parent the Shape under it.
g_cubeTransform = g_pack.createObject('Transform');
g_cubeTransform.addShape(cubeShape);
// Parent the cube's transform to the client root.
g_cubeTransform.parent = g_3dRoot;
// Generate the draw elements for the cube shape.
cubeShape.createDrawElements(g_pack, null);
// Create the global paint object that's used by draw operations.
g_paint = g_pack.createObject('CanvasPaint');
// Creates an instance of the canvas utilities library.
g_canvasLib = o3djs.canvas.create(g_pack, g_hudRoot, g_hudViewInfo);
// Create a canvas that will be used to display the text.
g_textCanvas = g_canvasLib.createXYQuad(70, 70, 0, 100, 50, true);
// Set our render callback for animation.
// This sets a function to be executed every time frame is rendered.
g_client.setRenderCallback(renderCallback);
//Set up a callback to interpret keypresses
window.document.onkeypress = keyPressedCallback;
//Set up mouse events
o3djs.event.addEventListener(g_o3dElement, 'mousedown', startDragging);
o3djs.event.addEventListener(g_o3dElement, 'mousemove', drag);
o3djs.event.addEventListener(g_o3dElement, 'mouseup', stopDragging);
o3djs.event.addEventListener(g_o3dElement, 'wheel', scrollMe);
}
/**
* Removes callbacks so they aren't called after the page has unloaded.
*/
function uninit() {
if (g_client) {
g_client.cleanup();
}
}
solidred.shader
// World View Projection matrix that will transform
// the input vertices to screen space.
float4x4 worldViewProjection : WorldViewProjection;
// input parameters for our vertex shader
struct VertexShaderInput {
float4 position : POSITION;
};
// input parameters for our pixel shader
struct PixelShaderInput {
float4 position : POSITION;
};
/**
* The vertex shader simply transforms input vertices to screen space
*/
PixelShaderInput vertexShaderFunction(VertexShaderInput input) {
PixelShaderInput output;
// Multiply the vertex positions by the worldViewProjection
// matrix to transform them to screen space.
output.position = mul(input.position, worldViewProjection);
return output;
}
/**
* This pixel shader just returns the color red.
*/
float4 pixelShaderFunction(PixelShaderInput input): COLOR {
return float4(1, 0, 0, 1); // Red.
}
// Here we tell our effect file *which* functions are
// our vertex and pixel shaders.
// #o3d VertexShaderEntryPoint vertexShaderFunction
// #o3d PixelShaderEntryPoint pixelShaderFunction
// #o3d MatrixLoadOrder RowMajor
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