Questions tagged [html-canvas]

A new feature of HTML5, allowing Javascript apps to have a drawing surface in the browser.

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1answer
4k views

Dealing With Multiple requestAnimationFrame Calls

I am having issues with requestAnimationFrame calls stacking on top of each other. I am developing a platformer game, which has three separate functions that need animating (main menu, cutscene, in ...
2
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3answers
307 views

Limit access to socket end point

I'm developing a multiplayer canvas game based on socket.io and box2d physics engine. Is there a way to limit connections to my socket endpoint and only allow connections from a specific domain? <...
1
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0answers
954 views

Detecting collision of multiple moving objects

I have wrote a simple game that has a 100 balls bouncing off the borders of the canvas. Each ball is an instance of ball class function that has the following ...
0
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1answer
389 views

js canvas tiled map - for loop, while, or matrix

I am making a top-down view tiled map in canvas, where player is always in the middle of the screen, and map scrolls depending on where you go, like in moba games. I also want it to loop infinitely in ...
0
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1answer
337 views

How to fill a canvas with triangles that are seemingly random?

Given a canvas say, 1000 X 1000 unit. I would like to fill the canvas with triangles. The triangles can be of any type right angle, equilateral...etc. To avoid big chunks of triangles lets say all ...
2
votes
1answer
257 views

Simulating elastic ball collisions quickly escalates to disaster

I'm trying to learn HTML canvas and was working on a basic physical simulation, where a number of balls are drawn and set in motion, and the program simulates them colliding and bouncing off the walls ...
3
votes
1answer
587 views

SDD Inverse Kinematics with constraints

I have a question regarding my quest on onderstanding IK solvers. After viewing this movie on YouTube: https://www.youtube.com/watch?v=MvuO9ZHGr6k I started recreating it with JavaScript. Just 2d on ...
1
vote
2answers
1k views

Canvas slowly degrades in performance after a while

I was creating a simple game and was shocked to see how the performance started to degrade. It never happened to me before, most probably because I use images and not the context drawings. So I used ...
2
votes
1answer
335 views

Fastest way to render isometric world with moving entities?

I've got an isometric diamond-shaped world. The world consists of isometric planes like rooms. The walls and floors of the rooms and all obstacles and items in the rooms are isometric entities. So I ...
0
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2answers
216 views

How to improve my graphics on HTML5 canvas?

I am making my own army fighting simulator. Designer have made an 3D model with Blender and textured it, made animations. I have made sprites from that model and did programming. But the result is not ...
4
votes
1answer
262 views

Updating code to include states

The Problem I am having a problem in that I am finding it hard to understand how to update my current code so that it uses states. I am creating a game, the game has a menu, each page in the game ...
0
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2answers
3k views

How can I move an object around a canvas in a random direction at random times?

I am currently trying to move an object (circle ball) around the canvas in a random direction. I have already written the code for the wall collisions so the ball bounces back into canvas when the ...
1
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1answer
1k views

How should I efficiently clear and redraw my canvas with lots of animated sprites?

My current solution is to clear the entire canvas and redraw all sprites on every requestFrame(). This works but feels inefficient: I only need to clear the part of the canvas made invalid by ...
0
votes
1answer
22 views

Mousedown event not performing drawImage

I've been working on the basic gameplay. I'm to a point where I think it should draw a card in the quadrant clicked/tapped, but nothing is happening. I can't see what's wrong. Please help. My only ...
0
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1answer
97 views

Why are my canvas drawings larger than the actual image?

For the following page source, I've finally gotten a grip on rendering the cards. I'm puzzled why they appear about 2.5x larger on the canvas. ...
2
votes
1answer
563 views

How to display a lot of small objects using WebGL?

Introduction The game scene contains a lot of 10x10 pixel elements: for 1980x1200 px. screen the number of elements on the scene can vary from 0 to 23760 (elements cannot intersect). The live ...
0
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1answer
40 views

HTML Canvas Makes Everything Bolder On Right Side

For some strange and sudden reason, my canvas seems to make lines thicker and darker on the right ~1/4-ish. I have tried multiple browsers and different computers and they all have the same rendering ...
1
vote
1answer
585 views

how to follow(center) a box inside canvas element

If inside a canvas I draw a box, and the I add arrows to move it, the box will eventually be out of my reach since it goes out the border and I cant see it. How could I follow the box so that it is ...
5
votes
1answer
415 views

Fixed Time Step Flutter

I've seen a lot of questions about this problem, but really no solution. Hopefully I can explain the issue well enough that I can get some sort of closure on this problem. I'm using a Fixed Time ...
1
vote
0answers
445 views

Using canvas graphics instead of traditional sprites in phaser

I'm trying to learn Phaser (total beginner with mild JS experience) and I'm following tutorials and such where everything is using sprites. I'm trying to get by with basic canvas shapes instead of ...
3
votes
0answers
231 views

Check if a point is touching a user drawn curve in HTML5 canvas

I am having trouble detecting whether a ball is colliding with a red curve. The curve below is an example of what a user may draw on to the canvas. I can't think of any fast ways to detect collision ...
3
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0answers
455 views

Drawing a hexgrid on a canvas, yet making it zoom/scrollable?

I'm developing a game in JS / PHP. The game is basically a 2D plane (hexgrid) where each hex represents a location in space. In total, I'm drawing 25 * 25 hexes on a 1000x1000 canvas. I also draw ...
2
votes
1answer
87 views

Best practice/way for client to speak with server

I'm making a multiplayer game in HTML5 Canvas and Node using Express and Socket.io. It's a platformer style game and so far the players are able to see each other and move around on the screen. It ...
1
vote
1answer
108 views

Javascript canvas check if all recs on the screen overlap a new one

So I know the AABB collision detection formula, however, this code does not work. Whenever I press space, a new square pops up. But this new square can spawn inside another, something that I do not ...
1
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0answers
128 views

Facebook Canvas (web) Game for Desktop & Mobile Browsers

as the title suggests - I am about to develop a game for FB canvas. Will the game support mobile and desktop or do I have to create two different project/game setups for this? thanks
1
vote
1answer
3k views

How do I check if one square is overlapping another in HTML5 canvas

I have a little program that goes like this: Whenever somebody presses space, a blue square appears. The blue square shouldn't overlap with any other blue square. But the function that is checking ...
5
votes
2answers
390 views

Create.js CPU High load

I'm new in Create.js and I'm trying to make countdown progress bar. I have this simple code: ...
1
vote
1answer
3k views

Android canvas.drawColor throws a null object reference

I have two nearly identical methods, the first to draw a splash screen while assets are loading, and the second to draw all of the assets to the screen. The first throws a NullPointerException on ...
6
votes
4answers
1k views

Rotating sprite around another sprite

I am building a pool game, and I want to make the cue rotate around the white ball. Here is the live code: http://199.26.84.223/nocol.html Here is the code for the white ball: ...
1
vote
1answer
1k views

Building a simple bomberman game with Node.js and Socket.io [closed]

I'm building this game mostly because I want to experiment with Node.js and Socket.io, and the game is more like a proof of concept. To start with, I have a 2D grid system as the game map. ...
2
votes
1answer
593 views

tilting image for mode7 game in HTML5

I'm making a mode7 game like mario-kart and I need to tilt the image before I draw it, I have tried using a buffer canvas to tilt the image then draw it on the games canvas but this makes it laggy (...
3
votes
1answer
4k views

JS Canvas - Creating 2D Game lighting effect like Terraria

I just started working with canvas in HTML5 and with javascript. I'm pretty satisfied with my game so far: http://xenopal.dk/game-v1.1/. But I'd like to implement lighting as well in the style of ...
2
votes
1answer
874 views

Drawing/adding shape objects with the mouse on html canvas

I've started with the canvas paint tutorial from link which worked fine with a few problems that can be fixed later. I've been checking a lot of posts on drawing shapes on the canvas but they all use ...
3
votes
1answer
1k views

Creating HTML5 Canvas Objects in Javascript [closed]

I'm currently trying to learn how to make HTML5 Canvas games with JavaScript. I would like to use object oriented JavaScript to manage the elements of the game, but i'm having trouble. I've done a lot ...
-2
votes
1answer
382 views

How do I clear the previous frames of a canvas animation?

I am trying to rotate an object, but all the previous frames still show up on the canvas. Here is my code. This didn't work: ...
0
votes
1answer
144 views

android canvas rope swing

I'm creating the code, where a player swinging on a rope for the moment I got this ...
1
vote
0answers
259 views

Donut-shaped / inverse mask in Phaser

I am trying to get a donut-shaped mask in Phaser (essentially the inverse of a regular mask). The mask shape is dynamic so it needs to be a Phaser.Graphics polygon object. Desired result: The blue ...
2
votes
1answer
260 views

Tiled - move all tiles

I'm making a map in Tiled. I quickly ran out of room in the north of my map and would like to "shift" the tiles down. I'd prefer not to have to redo each of the tile layers. Is this possible? This ...
1
vote
1answer
78 views

Why can't CSS Sprites handle vectors?

Almost all the documentation available either says that "sprites are bitmaps" or that "css sprites must be bitmaps". Is there a specific reason for this? Is it, in fact possible to create a css sprite ...
2
votes
3answers
789 views

How do I correctly make character sprite direction match player inputs?

In my top down game I can move the character around and the character will even face the direction he is moving. However, there is some weird behavior I'm having: when you hold down one direction and ...
5
votes
1answer
733 views

Roguelike 2D Collision Detection

I'm just a normal guy trying to do some basic collision detection but I suck at it. I either get stuck in a wall or I go in reverse in the wrong direction trying to update the player position to a non ...
-1
votes
1answer
2k views

Adding obstacles & collision to canvas game

I am trying to add some obstacles to the canvas game that I've got but something seems to be wrong and I can't seem to put my finger on it. I just want some simple walls here and there to make the ...
1
vote
1answer
311 views

svg spaceship game movement 2d

I've been searching for a way to make an svg box move to all directions using js. I have seen many tutorials on how to do it grid like, but I want it so have a square that can turn, move forward, ...
4
votes
1answer
1k views

Card Masking in Phaser

Good Day, I'm new to Phaser and still learning about it to. I am challenging my self to create a simple animation of a card flip somewhat realistic rather that making use of a scale. This is ...
0
votes
1answer
245 views

Rectangles clear each other when moving on canvas

I am having this problem after moving rectangles, they seem to delete one another. Most probably it is a problem with clearRect(...) method. This is the clean function I am using: ...
2
votes
0answers
58 views

CocoonJS draws shadow around tiles

I am using CocoonJS launcher on iOS for a simple tiled game. Calling canvas drawImage for tiles adds a shadow or ghost border around tiles. See this screenshot: http://martindrapeau.github.io/cocoon-...
1
vote
1answer
936 views

Cocos2D-JS Windows App in fullscreen mode (Win32)

I've been looking for a way to make my Cocos2D-JS app go into fullscreen mode, but there doesn't seem to be much documentation on Cocos2D-JS (or Cocos2D-x-js as some seem to call it.) This app is to ...
4
votes
1answer
904 views

How can I create 2D, sprite-based reflections in HTML5 Canvas?

I'm trying to create simple reflections in a 2D, sprite-based game using HTML5. I'm looking to recreate an effect like the one you'd often see in GBA games, such as Pokemon Emerald and Mother 3: ...
1
vote
1answer
4k views

Rotate arrow on canvas

I need to draw a flow dynamically based on some user choices. In that flow I want to draw the choices (blue circles with number) and the directions of that choices (line and arrow). For example: node ...
0
votes
1answer
812 views

How to draw small sprite bigger?

I have created an image with the resolution of 25px(width)*34px(height) (I know it's unusual, however it doesn't bother me now). The problem is that when I try to display it by creating a bitmap, it ...