The Lyceum Allotments |John Sharp's blog
posted by John Sharp on Jun 19, 2016

At long last we’ve reached a position where we can make a 2D game that is something like fully functional. As an illustration I’ve made a simple version of Snake, which can act as a guide for any projects that you’d like to do.

It doesn’t really cover anything conceptually new that we haven’t covered before, there’s just more of it, with multiple source files to be compiled. One problem that will be encountered if you just try and compile it using the previous command is that when you try and run the program you’ll be told that you’ve run out of memory.

For dynamic memory, Emscripten declares a JavaScript typed array and passes ‘pointers’ to that whenever the program requests some dynamic memory. To deal with a memory problem we simply need to make this typed array larger. By passing the command line argument -s TOTAL_MEMORY=67108864 to emcc a typed array of size 67108864 bytes (that is, 2^26 bytes) will be used, which should be enough.

If you’re not sure how much memory your program is going to use it is possible to pass the emcc command line argument -s ALLOW_MEMORY_GROWTH=1 which allows the memory array to grow if needs be, but this involves a performance cost.

[snake.html, snake.tar.gz,]