i have trouble having scale font in libgdx. I want use 1 file .fnt to 3 different font scale. But the result the font still have same scale whatever i scale them 1 by 1 .
this is my code, i'm using AssetManager.
// this is I load the assetsFont
// Settings.fileSilverBoldFont is font location.
// load font
manager.load(Settings.fileSilverBoldFont, BitmapFont.class);
BitmapFont defaultFont = manager.get(Settings.fileSilverBoldFont, BitmapFont.class);
// edited, old -> defaultSmall = defaultFont; (reference object, my fault)
BitmapFont defaultSmall= new BitmapFont(defaultFont.getData(), defaultFont.getRegion(), true);
BitmapFont defaultNormal= defaultFont.getCache().getFont();
BitmapFont defaultBig= new BitmapFont(defaultFont.getData(), defaultFont.getRegion(), false);;
// set font sizes
defaultSmall.setScale(0.75f / Settings.widthRatio, 0.75f / Settings.heightRatio);
defaultNormal.setScale(1.0f / Settings.widthRatio, 1.0f / Settings.heightRatio);
defaultBig.setScale(2.0f / Settings.widthRatio, 2.0f / Settings.heightRatio);
// enable linear texture filtering for smooth fonts
defaultSmall.getRegion().getTexture().setFilter(TextureFilter.Linear, TextureFilter.Linear);
defaultNormal.getRegion().getTexture().setFilter(TextureFilter.Linear, TextureFilter.Linear);
defaultBig.getRegion().getTexture().setFilter(TextureFilter.Linear, TextureFilter.Linear);
Then i fill my font to my game controller initFont().
public void initFont(){
distanceFont = new BitmapFontCache(Assets.assetFont.defaultBig).getFont();
scoreFont = new BitmapFontCache(Assets.assetFont.defaultSmall).getFont();
}
At last i Render my font to screen in render(), I call game controller using variable controller.
public void render(float delta){
controller.scoreFont.draw(hudBatch, controller.scoreText, 160/Settings.widthRatio, hudCam.viewportHeight - (40/ Settings.heightRatio));
controller.distanceFont.draw(hudBatch, controller.distanceText, hudCam.viewportWidth/2, hudCam.viewportHeight - (40/ Settings.heightRatio));
}
I want to have scoreFont draw Small and distanceFont draw big font. but the result 2 of them still have same size. How can i have my scoreFont draw with small font and distanceFont draw with big font ?
found about reference object in java, now i'm change using new object of it, and it still same, I can't have different size of font.
Okey now i found, I must load using BitmapFont directly multiple times, this is solution what i do. I don't know how to use AssetManager properly to do that, maybe this is enough for this case.
// create three fonts using Libgdx's built-in 15px bitmap font
silverBoldSmall = new BitmapFont(Gdx.files.internal(Settings.fileSilverBoldFont));
silverBoldNormal = new BitmapFont(Gdx.files.internal(Settings.fileSilverBoldFont));
silverBoldBig = new BitmapFont(Gdx.files.internal(Settings.fileSilverBoldFont));
// set font sizes
silverBoldSmall.setScale(2f / Settings.widthRatio, 2f / Settings.heightRatio);
silverBoldNormal.setScale(3f / Settings.widthRatio, 3f / Settings.heightRatio);
silverBoldBig.setScale(4f / Settings.widthRatio, 4f / Settings.heightRatio);
You've only got one font instance.
BitmapFont defaultSmall= defaultFont;
BitmapFont defaultNormal= defaultFont;
BitmapFont defaultBig= defaultFont;
Then you change the scale three times on the same font...
defaultSmall.setScale(0.75f / Settings.widthRatio, 0.75f / Settings.heightRatio);
defaultNormal.setScale(1.0f / Settings.widthRatio, 1.0f / Settings.heightRatio);
defaultBig.setScale(2.0f / Settings.widthRatio, 2.0f / Settings.heightRatio);
If pointing this out doesn't make sense then you read up on how references work in Java.
I must load using BitmapFont directly multiple times, maybe this is enough for this case.
// create three fonts using Libgdx's built-in 15px bitmap font
BitmapFont defaultSmall= new BitmapFont(Gdx.files.internal(Settings.fileSilverBoldFont));
BitmapFont defaultNormal= new BitmapFont(Gdx.files.internal(Settings.fileSilverBoldFont));
BitmapFont defaultBig= new BitmapFont(Gdx.files.internal(Settings.fileSilverBoldFont));
I know this is old, but this my be relevant to people browsing still.
If you are grabbing your font from a skin (ex. font = skin.getFont("fontName")), a solution is to modify your json file and define multiple fonts which all point to the same font in your atlas.
In my case this looks like this
com.badlogic.gdx.graphics.g2d.BitmapFont: {
HelveticaNeue-Light: {
file: HelveticaNeue-Light.fnt
}
HelveticaNeue-Light2: {
file: HelveticaNeue-Light.fnt
}
}
And then when grabbing the fonts from your skin, you can access the multiple different ones which will create separate instances.
Related
The past few days I've been trying to figure out a display bug I don't understand. I've been working on a simple 2d platformer with box2d and orthogonal Tiled maps. So far so good, the physics work and using the b2d debug renderer I can assert proper player fixture and camera movement through the level.
Now next step I've tried to load textures to display sprites instead of debug shapes. This is where I stumble. I can load animations for my player body/fixture, but when I use the setCenter() method to center the texture on the fixture it is always out of center.
I've tried approaches via halving texture witdths and heights hoping to center the texture on the player fixture but I get the exact same off position rendering. I've played aorund with world/camera/screen unit coordinates but the misalignement persists.
I'm creating the player in my Player class with the following code.
First I define the player in box2d:
//define player's physical behaviour
public void definePlayer() {
//definitions to later use in a body
BodyDef bdef = new BodyDef();
bdef.position.set(120 / Constants.PPM, 60 / Constants.PPM);
bdef.type = BodyDef.BodyType.DynamicBody;
b2body = world.createBody(bdef);
//Define needed components of the player's main fixture
FixtureDef fdef = new FixtureDef();
PolygonShape shape = new PolygonShape();
shape.setAsBox(8 / Constants.PPM, 16 / Constants.PPM); //size of the player hitbox
//set the player's category bit
fdef.filter.categoryBits = Constants.PLAYER_BIT;
//set which category bits the player should collide with. If not mentioned here, no collision occurrs
fdef.filter.maskBits = Constants.GROUND_BIT |
Constants.GEM_BIT |
Constants.BRICK_BIT |
Constants.OBJECT_BIT |
Constants.ENEMY_BIT |
Constants.TREASURE_CHEST_BIT |
Constants.ENEMY_HEAD_BIT |
Constants.ITEM_BIT;
fdef.shape = shape;
b2body.createFixture(fdef).setUserData(this);
}
Then I call the texture Region to be drawn in the Player class constructor:
//define in box2d
definePlayer();
//set initial values for the player's location, width and height, initial animation.
setBounds(0, 0, 64 / Constants.PPM, 64 / Constants.PPM);
setRegion(playerStand.getKeyFrame(stateTimer, true));
And finally, I update() my player:
public void update(float delta) {
//center position of the sprite on its body
// setPosition(b2body.getPosition().x - getWidth() / 2, b2body.getPosition().y - getHeight() / 2);
setCenter(b2body.getPosition().x, b2body.getPosition().y);
setRegion(getFrame(delta));
//set all the boolean flags during update cycles approprietly. DO NOT manipulate b2bodies
//while the simulation happens! therefore, only set flags there, and call the appropriate
//methods outside the simulation step during update
checkForPitfall();
checkIfAttacking();
}
And my result is
this, facing right
and this, facing left
Update:
I've been trying to just run
setCenter(b2body.getPosition().x, b2body.getPosition().y);
as suggested, and I got the following result:
facing right and facing left.
The sprite texture flip code is as follows:
if((b2body.getLinearVelocity().x < 0 || !runningRight) && !region.isFlipX()) {
region.flip(true, false);
runningRight = false;
} else if ((b2body.getLinearVelocity().x > 0 || runningRight) && region.isFlipX()) {
region.flip(true, false);
runningRight = true;
}
I'm testing if either the boolean flag for facing right is set or the x-axis velocity of my player b2body has a positive/negative value and if my texture region is already flipped or not and then use libGDX's flip() accordingly. I should not be messing with fixture coords anywhere here, hence my confusion.
The coordinates of box2d fixtures are offsets from the position, the position isn't necessarily the center (although it could be depending on your shape definition offsets). So in your case i think the position is actually the lower left point of the box2d polygon shape.
In which case you don't need to adjust for width and height because sprites are also drawn from bottom left position. So all you need is ;
setPosition(b2body.getPosition().x , b2body.getPosition().y );
I'm guessing you flip the box2d body when the player looks left the position of the shape is now bottom right so the sprite offset of width/2 and height/2 is from the bottom right instead. So specifically when you are looking left you need an offset of
setPosition(b2body.getPosition().x - getWidth() , b2body.getPosition().y );
I think looking right will be fixed from this, but i don't know for sure how you handle looking left in terms of what you do to the body, but something is done because the offset changes entirely as shown in your capture. If you aren't doing some flipping you could add how you handle looking right to the question.
EDIT
It seems the answer was that the sprite wasn't centered in the sprite sheet and this additional space around the sprite caused the visual impression of being in the wrong place (see comments).
I want to create some effects in cocos2d-x by updating raw color data of sprite, does cocos2d-x supply any ways to do that?
Update: My buffer is 4-bytes (A-R-G-B) for each pixels, viewport dimensions are 640x480. So, the buffer has 640 * 480 * 4 = 1228800 bytes in length and I update its content frequently.
This solution regenerates the texture each time it is changed.
Note: the texture in this code uses the format RGBA - not ARGB.
The data(/texel) array m_TextureData and the sprite are allocated only once but the Texture2D object has to be released and recreated every time which might be a performance issue.
Note: the class names are the new ones from Cocos2d-x 3.1.x. In the main loop there's an alternative part for 2.2.x users. To use that one you have to use also the old class names (like ccColor4B, CCTexture2D, CCSprite).
in header:
Color4B *m_TextureData;
Texture2D *m_Texture;
Sprite *m_Sprite;
in implementation:
int w = 640; // width of texture
int h = 480; // height of texture
m_TextureData = new Color4B[w * h];
set colors directly - e.g.:
Color4B white;
white.r = 255;
white.g = 255;
white.b = 255;
white.a = 255;
m_TextureData[i] = white; // i is an index running from 0 to w*h-1
use data to initialize texture:
CCSize contentSize;
contentSize.width = w;
contentSize.height = h;
m_Texture = new Texture2D;
m_Texture->initWithData(m_TextureData, kCCTexture2DPixelFormat_RGBA8888, w, h, contentSize);
create a Sprite with this texture:
m_Sprite = Sprite::createWithTexture(m_Texture);
m_Sprite->retain();
add m_Sprite to your scene
in main loop:
to change color/texels of texture dynamically modify m_TextureData:
m_TextureData[i] = ...;
in Cocos2d-x 2.x:
In 2.2.x you actually have to release the old texture and create a new one:
m_Texture->release(); // make sure that ccGLDeleteTexture() is called internally to prevent memory leakage
m_Texture = new Texture2D;
m_Texture->initWithData(m_TextureData, kCCTexture2DPixelFormat_RGBA8888, w, h, contentSize);
m_Sprite->setTexture(m_Texture); // update sprite with new texture
in Cocos2d-x 3.1.x
m_Texture->updateWithData(m_TextureData, 0, 0, w, h);
Later, don't forget to clean up.
in destructor:
m_Sprite->release();
m_Texture->release();
delete [] m_TextureData;
I am building a windows phone 8 camera app. After a photograph has been taken i want to give the user the option of cropping specific part of the image. Like if there are some specific objects in the image, when crop option is selected, it should highlight or outline that specific part of the image, and it should be able to crop it, rather than manually cropping it.
Any specific ways to do it?.
Thanks In advance.
One way would be to create a WriteableBitmap and do a TranslateTransform of the original image into the WritableBitmap. Something like::
Image workImage = new Image { Source = originalImage, Width = originalWidth, Height = originalHeight };
WriteableBitmap writeableBitmap = new WriteableBitmap(newWidth, newHeight);
writeableBitmap.Render(temporaryImage, new TranslateTransform { X = (originalWidth – newWidth) / -2, Y = (originalHeight – newHEight) / -2 });
writeableBitmap.Invalidate();
//... or some other stream
Stream newImageStream = new MemoryStream();
//set whatever quality settings you like if 75 is no good
writeableBitmap.SaveJpeg(newImageStream, newWidth, newHeight, 0, 75);
// TODO: do something with newImageStream
I try to draw simple text in my android game on libgdx, but it's look sharp. How to make text look smooth in different resolutions? My Code:
private BitmapFont font;
font = new BitmapFont();
font.scale((ppuX*0.02f));
font.draw(spb, "Score:", width/2-ppuX*2f, height-0.5f*ppuY);
font.getRegion().getTexture().setFilter(TextureFilter.Linear, TextureFilter.Linear);
This gets the texture used in a BitmapFont and changes its filtering to bilinear, allowing higher resulting image quality while both up- and downscaling it at the cost of slightly slower (the difference is usually not noticeable) GPU rendering.
One solution is to use the FreeType extension to libgdx, as described here. This allows you to generate a bitmap font on the fly from a .ttf font. Typically you would do this at startup time once you know the target resolution.
Here's an example:
int viewportHeight;
BitmapFont titleFont;
BitmapFont textFont;
private void createFonts() {
FileHandle fontFile = Gdx.files.internal("data/Roboto-Bold.ttf");
FreeTypeFontGenerator generator = new FreeTypeFontGenerator(fontFile);
FreeTypeFontParameter parameter = new FreeTypeFontParameter();
parameter.size = 12;
textFont = generator.generateFont(parameter);
parameter.size = 24;
titleFont = generator.generateFont(parameter);
generator.dispose();
}
You should definitly have a quick look on custom font shaders and/or DistanceField-Fonts. They're easy to understand and similarly easy to implement:
https://github.com/libgdx/libgdx/wiki/Distance-field-fonts
DistanceFieldFonts stay smooth, even when you upscale them:
Create a .fnt file using hiero which is provided by libgdx website.
Set the size of font to 150; it will create a .fnt file and a .png file.
Copy both files into your assets folder.
Now declare the font:
BitmapFont font;
Now in create method:
font = new BitmapFont(Gdx.files.internal("data/100.fnt"), false); // 100 is the font name you can give your font any name
In render:
font.setscale(.2f);
font.draw(batch, "whatever you want to write", x,y);
In general you don't get sharp text because you are designing your game for a certain resolution and when you move to a different device, Libgdx scales everything to match the new resolution. Even with linear filtering scaling is bad on text because round corners are easily distorted. In a perfect world you would create the content dynamically at runtime according to the number of pixels available to you and not a single automatic scale would be used.
This is the approach I'm using: Building everything for small screen (480 x 320), and when you open it on a bigger resolution, I load the BitmapFont with a higher size and apply and inverse scale to the one that Libgdx will later do automatically.
Here's an example to make things clearer:
public static float SCALE;
public static final int VIRTUAL_WIDTH = 320;
public static final int VIRTUAL_HEIGHT = 480;
public void loadFont(){
// how much bigger is the real device screen, compared to the defined viewport
Screen.SCALE = 1.0f * Gdx.graphics.getWidth() / Screen.VIRTUAL_WIDTH ;
// prevents unwanted downscale on devices with resolution SMALLER than 320x480
if (Screen.SCALE<1)
Screen.SCALE = 1;
FreeTypeFontGenerator generator = new FreeTypeFontGenerator(Gdx.files.internal("data/Roboto-Regular.ttf"));
// 12 is the size i want to give for the font on all devices
// bigger font textures = better results
labelFont = generator.generateFont((int) (12 * SCALE));
// aplly the inverse scale of what Libgdx will do at runtime
labelFont.setScale((float) (1.0 / SCALE));
// the resulting font scale is: 1.0 / SCALE * SCALE = 1
//Apply Linear filtering; best choice to keep everything looking sharp
labelFont.getRegion().getTexture().setFilter(TextureFilter.Linear, TextureFilter.Linear);
}
Bitmap fonts are textures and if you want to make smaller textures look smoother when you are resizing them to bigger sizes you need to make sure you use the right texture filter.
This blog post deals with such issues
With many things deprecated after the update, this is what's working for me:
public void regenerateFonts(OrthographicCamera cam, Game game) {
int size = 18;
if (cam != null && game != null) {
// camera and game are provided, recalculate sizes
float ratioX = cam.viewportWidth / game.getW();
float ratioY = cam.viewportHeight / game.getH();
System.out.println("Ratio: [" + ratioX + ":" + ratioY + "]");
size *= ratioY;
}
// font parameters for this size
FreeTypeFontParameter params = new FreeTypeFontParameter();
params.flip = true; // if your cam is flipped
params.characters = LETTERS; // your String containing all letters you need
params.size = size;
params.magFilter = TextureFilter.Linear; // used for resizing quality
params.minFilter = TextureFilter.Linear; // also
// Lato Light generator
FreeTypeFontGenerator generator = new FreeTypeFontGenerator(Gdx.files.internal("fonts/Lato-Light.ttf"));
// make the font
fontLatoLight = generator.generateFont(params);
generator.dispose(); // dispose to avoid memory leaks
}
And when you want to render it on the screen:
// text rendering
fontLatoLight.setColor(Color.WHITE); // set color here (has other overloads too)
fontLatoLight.draw(batch, "Hello World!", xCoord, yCoord);
My Solution for smooth text with Libgdx
I use BitmapFont and I generate 3 different size same fonts using Hiero tool
example Arial 16 , Arial 32, Arial 64
I put them in my assets file and use (load) only one of them depeding on the size of screen
if(Gdx.graphics.getWidth() < (480*3)/2)
{
textGametFont = BitmapFont(Gdx.files.internal(nameFont+16+".fnt"),
Gdx.files.internal(nameFont+16+".png"), false);
}else
{
if(Gdx.graphics.getWidth() < (3*920)/2)
{
textGametFont = new BitmapFont(Gdx.files.internal(nameFont+32+".fnt"),
Gdx.files.internal(nameFont+32+".png"), false);
}else
{
textGametFont = new BitmapFont(Gdx.files.internal(nameFont+64+".fnt"),
Gdx.files.internal(nameFont+64+".png"), false);
}
}
then I use this line of code to higher result quality of down and up Scaling
textGametFont.getRegion().getTexture().setFilter(TextureFilter.Linear, TextureFilter.Linear);
scale the image
to handle the size of the font for all type of resolution of device I use those two functions
public static float xTrans(float x)
{
return x*Gdx.graphics.width/(YourModel.SCREEN_WIDTH);
}
public static float yTrans(float y)
{
return y*Gdx.graphics.height/YourModel.SCREEN_Height;
}
the model screen resolution that i use is
SCREEN_WIDTH = 480
SCREEN_HEIGHT = 320
Set the scale to the font
textGametFont.setScale((xtrans(yourScale)+ ytrans(yourScale))/2f);
and finally draw your text
textGametFont.draw(batch, "WINNER !!", xTrans(250), yTrans(236));
Hope this was clear and helpful !!!
private BitmapFont font;
font = new BitmapFont();
font.scale((ppuX*0.02f));
font.draw(spb, "Score:", width/2-ppuX*2f, height-0.5f*ppuY);
Check out [this](http://www.badlogicgames.com/wordpress/?p=2300) blog post.
??? This just explains how to use the .scale() method which I'm stating is deprecated in the current release.
In scene2d, if you want apply antialiasing to all your labels, put this on constructor of your first screen:
skin.getFont("default-font").getRegion().getTexture().setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear);
This is the first screen in my game:
...
public class MainMenuScreen implements Screen {
public MainMenuScreen() {
...
skin.getFont("default-font").getRegion().getTexture().setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear);
}
}
Font name is in ui.json file, check for BitmapFont and Label$LabelStyle section:
"com.badlogic.gdx.graphics.g2d.BitmapFont": {
"default-font": {
"file": "default.fnt"
}
},
"com.badlogic.gdx.scenes.scene2d.ui.Label$LabelStyle": {
"default": {
"font": "default-font",
"fontColor": "white",
}
},
I want to draw a 3D ball or sphere in HTML 5.0 canvas. I want to understand the Algorithm about how to draw a 3D sphere. Who can share this with me?
You will need to model a sphere, and have it be varying colors so that as it rotates you can see that it is not only a sphere, but being rendered.
Otherwise, a sphere in space, with not point of reference around it looks like a circle, if it is all one solid color.
To start with you will want to try drawing a circle with rectangles, as that is the main primitive you have.
Once you understand how to do that, or create a new primitive, such as a triangle, using the Path method, and create a circle, then you are ready to move it to 3D.
3D is just a trick, as you will take your model, probably generated by an equation, and then flatten it, as you determine which parts will be seen, and then display it.
But, you will want to change the color of the triangles based on how far they are from a source of light, as well as based on the angle of that part to the light source.
This is where you can start to do optimizations, as, if you do this pixel by pixel then you are raytracing. If you have larger blocks, and a point source of light, and the object is rotating but not moving around then you can recalculate how the color changes for each triangle, then it is just a matter of changing colors to simulate rotating.
The algorithm will depend on what simplifications you want to make, so as you gain experience come back and ask, showing what you have done so far.
Here is an example of doing it, and below I copied the 3D sphere part, but please look at the entire article.
function Sphere3D(radius) {
this.point = new Array();
this.color = "rgb(100,0,255)"
this.radius = (typeof(radius) == "undefined") ? 20.0 : radius;
this.radius = (typeof(radius) != "number") ? 20.0 : radius;
this.numberOfVertexes = 0;
// Loop from 0 to 360 degrees with a pitch of 10 degrees ...
for(alpha = 0; alpha <= 6.28; alpha += 0.17) {
p = this.point[this.numberOfVertexes] = new Point3D();
p.x = Math.cos(alpha) * this.radius;
p.y = 0;
p.z = Math.sin(alpha) * this.radius;
this.numberOfVertexes++;
}
// Loop from 0 to 90 degrees with a pitch of 10 degrees ...
// (direction = 1)
// Loop from 0 to 90 degrees with a pitch of 10 degrees ...
// (direction = -1)
for(var direction = 1; direction >= -1; direction -= 2) {
for(var beta = 0.17; beta < 1.445; beta += 0.17) {
var radius = Math.cos(beta) * this.radius;
var fixedY = Math.sin(beta) * this.radius * direction;
for(var alpha = 0; alpha < 6.28; alpha += 0.17) {
p = this.point[this.numberOfVertexes] = new Point3D();
p.x = Math.cos(alpha) * radius;
p.y = fixedY;
p.z = Math.sin(alpha) * radius;
this.numberOfVertexes++;
}
}
}
}
u can try with three.js library , which abstracts a lot of code from core webgl programming. Include three.js library in your html from three.js lib.
u can use canvas renderer for safari browser , webgl works for chrome
please find the JS FIDDLE FOR SPHERE
var camera, scene, material, mesh, geometry, renderer
function drawSphere() {
init();
animate();
}
function init() {
// camera
scene = new THREE.Scene()
camera = new THREE.PerspectiveCamera(50, window.innerWidth / innerHeight, 1, 1000);
camera.position.z = 300;
scene.add(camera);
// sphere object
var radius = 50,
segments = 10,
rings = 10;
geometry = new THREE.SphereGeometry(radius, segments, rings);
material = new THREE.MeshNormalMaterial({
color: 0x002288
});
mesh = new THREE.Mesh(geometry, material);
//scene
;
scene.add(mesh);
// renderer
renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
}
function animate() {
requestAnimationFrame(animate);
render();
}
function render() {
mesh.rotation.x += .01;
mesh.rotation.y += .02;
renderer.render(scene, camera);
}
// fn callin
drawSphere();
Update: This code is quite old and limited. There are libraries for doing 3D spheres now: http://techslides.com/d3-globe-with-canvas-webgl-and-three-js/
Over ten years ago I wrote a Java applet to render a textured sphere by actually doing the math to work out where the surface of the sphere was in the scene (not using triangles).
I've rewritten it in JavaScript for canvas and I've got a demo rendering the earth as a sphere:
(source: haslers.info)
I get around 22 fps on my machine. Which is about as fast as the Java version it was based on renders at, if not a little faster!
Now it's a long time since I wrote the Java code - and it was quite obtuse - so I don't really remember exactly how it works, I've just ported it JavaScript. However this is from a slow version of the code and I'm not sure if the faster version was due to optimisations in the Java methods I used to manipulate pixels or from speedups in the math it does to work out which pixel to render from the texture. I was also corresponding at the time with someone who had a similar applet that was much faster than mine but again I don't know if any of the speed improvements they had would be possible in JavaScript as it may have relied on Java libraries. (I never saw their code so I don't know how they did it.)
So it may be possible to improve on the speed. But this works well as a proof of concept.
I'll have a go at converting my faster version some time to see if I can get any speed improvements into the JavaScript version.
Well, an image of a sphere will always have a circular shape on your screen, so the only thing that matters is the shading. This will be determined by where you place your light source.
As for algorithms, ray tracing is the simplest, but also the slowest by far — so you probably wouldn't want to use it to do anything very complicated in a <CANVAS> (especially given the lack of graphics acceleration available in that environment), but it might be fast enough if you just wanted to do a single sphere.