I'm sure this was solven 1000 times before: I got a canvas in the size of 960*560 and a room in the size of 5000*3000 of which always only 960*560 should be drawn, depending on where the player is. The player should be always in the middle, but when near to borders - then the best view should be calculated). The player can move entirely free with WASD or the arrow keys. And all objects should move themselves - instead of that i move everything else but the player to create the illusion that the player moves.
I now found those two quesitons:
HTML5 - Creating a viewport for canvas works, but only for this type of game, i can't reproduce the code for mine.
Changing the view "center" of an html5 canvas seems to be more promising and also perfomant, but i only understand it for drawing all other objects correctly relative to the player and not how to scroll the canvas viewport relative to the player, which i want to achieve first of course.
My code (simplified - the game logic is seperately):
var canvas = document.getElementById("game");
canvas.tabIndex = 0;
canvas.focus();
var cc = canvas.getContext("2d");
// Define viewports for scrolling inside the canvas
/* Viewport x position */ view_xview = 0;
/* Viewport y position */ view_yview = 0;
/* Viewport width */ view_wview = 960;
/* Viewport height */ view_hview = 560;
/* Sector width */ room_width = 5000;
/* Sector height */ room_height = 3000;
canvas.width = view_wview;
canvas.height = view_hview;
function draw()
{
clear();
requestAnimFrame(draw);
// World's end and viewport
if (player.x < 20) player.x = 20;
if (player.y < 20) player.y = 20;
if (player.x > room_width-20) player.x = room_width-20