Octarine

Octarine is a game engine written in C for C/C++ designed to be used on 2D games with fixed-timestep logic. The renderer is able to automatically interpolate draws to render at unlocked framerates while the user need not concern themselves with anything other than game logic.

Warning

Octarine was made and continues to exist soley as a way for me to make jam games quickly in a comfortable environment. To this end, it's quite stable and has more than enough features to make game dev much quicker, but it will likely not recieve new features unless someone PRs them or I want them in a future jam.

Notable Features

• Logic is done on its own thread, drawing must be done by queueing draws for the main thread
• Fixed-timestep logic with interpolation makes physics incredibly simple without sacrificing visuals
• Performant and safe(r) allocators are provided for the user
• Fixed time-step with interpolation is the default and incredibly simple to use (and quite fast!)
• Robust asset bundle system that works with directories or archives (Thanks PhysFS!)

Example

This example program displays a rectangle going in circles, where the rectangle will be drawn at an uncapped, interpolated framerate but the update function will only update 30 times a second. To see the difference, draw another rectangle near the original one without interpolation and you will see the difference clear as day.

#include <oct/Octarine.h>
#include <math.h>

void *startup() {
    // ...
}

void *update(void *ptr) {
    oct_DrawRectangleInt(
        ctx, 
        OCT_INTERPOLATE_ALL, 1,
        &(Oct_Rectangle){
            .position = {320 + (cosf(oct_Time(ctx)) * 200), 240 + (sinf(oct_Time(ctx)) * 200)},
            .size = {40, 40}
        },
        true, 0
    );
}

void shutdown(void *ptr) {
    // ...
}

int main(int argc, const char **argv) {
    Oct_InitInfo initInfo = {
            .sType = OCT_STRUCTURE_TYPE_INIT_INFO,
            .startup = startup,
            .update = update,
            .shutdown = shutdown,
            .argc = argc,
            .argv = argv,
            .windowTitle = "Octarine",
            .windowWidth = 640,
            .windowHeight = 480,
            .debug = true,
    };

    oct_Init(&initInfo);
    return 0;
}

Libraries it uses

Library	Purpose	License
Vulkan2D	Rendering	zlib
SDL3	Windowing/input/threads/audio	zlib
SDL3_ttf	Font rendering	zlib
mi-malloc	Memory management	MIT
PhysicsFS	Asset system	zlib
stb_vorbis	Parsing OGGs	MIT
cJSON	Parsing JSONs	MIT
VulkanMemoryAllocator (VMA)	Vulkan2D uses it	MIT
tinyobjloader-c	Vulkan2D uses it	MIT
stb_image	Vulkan2D uses it	MIT
FreeType	SDL3_ttf uses it	FTL
HarfBuzz	SDL3_ttf uses it	MIT
PlutoSVG	SDL3_ttf uses it	MIT
PlutoVG	SDL3_ttf uses it	MIT