Sokol
Simple STB-style cross-platform libraries for C and C++, written in C.
See what's new (20-Feb-2023 a new set of functions in sokol_gfx.h to get a pre-filled 'desc struct' for a resource)
Examples and Related Projects
-
Live Samples via WASM (source)
-
Doom Shareware ported to the Sokol headers (source)
-
sokol_gp.h a 2D shape drawing library on top of sokol_gfx.h
-
LearnOpenGL examples ported to sokol-gfx by @geertarien (cool stuff!)
-
Dear ImGui starterkit a self-contained starterkit for writing Dear ImGui apps in C.
-
qoiview a basic viewer for the new QOI image file format
-
A 'single-file' Pacman clone in C99, also available in Zig
-
A Minigolf game (source).
-
Command line tools (shader compiler)
-
How to build without a build system: useful details for integrating the Sokol headers into your own project with your favourite C/C++ build system
Core libraries
- sokol_gfx.h: 3D-API wrapper (GL + Metal + D3D11)
- sokol_app.h: app framework wrapper (entry + window + 3D-context + input)
- sokol_time.h: time measurement
- sokol_audio.h: minimal buffer-streaming audio playback
- sokol_fetch.h: asynchronous data streaming from HTTP and local filesystem
- sokol_args.h: unified cmdline/URL arg parser for web and native apps
- sokol_log.h: provides a standard logging callback for the other sokol headers
Utility libraries
- sokol_imgui.h: sokol_gfx.h rendering backend for Dear ImGui
- sokol_nuklear.h: sokol_gfx.h rendering backend for Nuklear
- sokol_gl.h: OpenGL 1.x style immediate-mode rendering API on top of sokol_gfx.h
- sokol_fontstash.h: sokol_gl.h rendering backend for fontstash
- sokol_gfx_imgui.h: debug-inspection UI for sokol_gfx.h (implemented with Dear ImGui)
- sokol_debugtext.h: a simple text renderer using vintage home computer fonts
- sokol_memtrack.h: easily track memory allocations in sokol headers
- sokol_shape.h: generate simple shapes and plug them into sokol-gfx resource creation structs
- sokol_color.h: X11 style color constants and functions for creating sg_color objects
- sokol_spine.h: a sokol-style wrapper around the Spine C runtime (http://en.esotericsoftware.com/spine-in-depth)
'Official' Language Bindings
These are automatically updated on changes to the C headers:
Notes
WebAssembly is a 'first-class citizen', one important motivation for the Sokol headers is to provide a collection of cross-platform APIs with a minimal footprint on the web platform while still being useful.
The core headers are standalone and can be used independently from each other.
Why C:
- easier integration with other languages
- easier integration into other projects
- adds only minimal size overhead to executables
A blog post with more background info: A Tour of sokol_gfx.h
sokol_gfx.h:
- simple, modern wrapper around GLES2/WebGL, GLES3/WebGL2, GL3.3, D3D11 and Metal
- buffers, images, shaders, pipeline-state-objects and render-passes
- does not handle window creation or 3D API context initialization
- does not provide shader dialect cross-translation (BUT there's now an 'official' shader-cross-compiler solution which seamlessly integrates with sokol_gfx.h and IDEs: see here for details
A triangle in C99 with GLFW:
#define SOKOL_IMPL
#define SOKOL_GLCORE33
#include "sokol_gfx.h"
#include "sokol_log.h"
#define GLFW_INCLUDE_NONE
#include "GLFW/glfw3.h"
int main() {
/* create window and GL context via GLFW */
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* w = glfwCreateWindow(640, 480, "Sokol Triangle GLFW", 0, 0);
glfwMakeContextCurrent(w);
glfwSwapInterval(1);
/* setup sokol_gfx */
sg_setup(&(sg_desc){
.logger.func = slog_func,
});
/* a vertex buffer */
const float vertices[] = {
// positions // colors
0.0f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f
};
sg_buffer vbuf = sg_make_buffer(&(sg_buffer_desc){
.data = SG_RANGE(vertices)
});
/* a shader */
sg_shader shd = sg_make_shader(&(sg_shader_desc){
.vs.source =
"#version 330\n"
"layout(location=0) in vec4 position;\n"
"layout(location=1) in vec4 color0;\n"
"out vec4 color;\n"
"void main() {\n"
" gl_Position = position;\n"
" color = color0;\n"
"}\n",
.fs.source =
"#version 330\n"
"in vec4 color;\n"
"out vec4 frag_color;\n"
"void main() {\n"
" frag_color = color;\n"
"}\n"
});
/* a pipeline state object (default render states are fine for triangle) */
sg_pipeline pip = sg_make_pipeline(&(sg_pipeline_desc){
.shader = shd,
.layout = {
.attrs = {
[0].format=SG_VERTEXFORMAT_FLOAT3,
[1].format=SG_VERTEXFORMAT_FLOAT4
}
}
});
/* resource bindings */
sg_bindings bind = {
.vertex_buffers[0] = vbuf
};
/* default pass action (clear to grey) */
sg_pass_action pass_action = {0};
/* draw loop */
while (!glfwWindowShouldClose(w)) {
int cur_width, cur_height;
glfwGetFramebufferSize(w, &cur_width, &cur_height);
sg_begin_default_pass(&pass_action, cur_width, cur_height);
sg_apply_pipeline(pip);
sg_apply_bindings(&bind);
sg_draw(0, 3, 1);
sg_end_pass();
sg_commit();
glfwSwapBuffers(w);
glfwPollEvents();
}
/* cleanup */
sg_shutdown();
glfwTerminate();
return 0;
}
sokol_app.h
A minimal cross-platform application-wrapper library:
- unified application entry
- single window or canvas for 3D rendering
- 3D context initialization
- event-based keyboard, mouse and touch input
- supported platforms: Win32, MacOS, Linux (X11), iOS, WASM, Android, UWP
- supported 3D-APIs: GL3.3 (GLX/WGL), Metal, D3D11, GLES2/WebGL, GLES3/WebGL2
A simple clear-loop sample using sokol_app.h and sokol_gfx.h (does not include separate sokol.c/.m implementation file which is necessary to split the Objective-C code from the C code of the sample):
#include "sokol_gfx.h"
#include "sokol_app.h"
#include "sokol_log.h"
#include "sokol_glue.h"
sg_pass_action pass_action;
void init(void) {
sg_setup(&(sg_desc){
.context = sapp_sgcontext(),
.logger.func = slog_func,
});
pass_action = (sg_pass_action) {
.colors[0] = { .action=SG_ACTION_CLEAR, .value={1.0f, 0.0f, 0.0f, 1.0f} }
};
}
void frame(void) {
float g = pass_action.colors[0].value.g + 0.01f;
pass_action.colors[0].value.g = (g > 1.0f) ? 0.0f : g;
sg_begin_default_pass(&pass_action, sapp_width(), sapp_height());
sg_end_pass();
sg_commit();
}
void cleanup(void) {
sg_shutdown();
}
sapp_desc sokol_main(int argc, char* argv[]) {
return (sapp_desc){
.init_cb = init,
.frame_cb = frame,
.cleanup_cb = cleanup,
.width = 400,
.height = 300,
.window_title = "Clear Sample",
.logger.func = slog_func,
};
}
sokol_audio.h
A minimal audio-streaming API:
- you provide a mono- or stereo-stream of 32-bit float samples which sokol_audio.h forwards into platform-specific backends
- two ways to provide the data:
- directly fill backend audio buffer from your callback function running in the audio thread
- alternatively push small packets of audio data from your main loop, or a separate thread created by you
- platform backends:
- Windows: WASAPI
- macOS/iOS: CoreAudio
- Linux: ALSA
- emscripten: WebAudio + ScriptProcessorNode (doesn't use the emscripten-provided OpenAL or SDL Audio wrappers)
A simple mono square-wave generator using the callback model:
// the sample callback, running in audio thread
static void stream_cb(float* buffer, int num_frames, int num_channels) {
assert(1 == num_channels);
static uint32_t count = 0;
for (int i = 0; i < num_frames; i++) {
buffer[i] = (count++ & (1<<3)) ? 0.5f : -0.5f;
}
}
int main() {
// init sokol-audio with default params
saudio_setup(&(saudio_desc){
.stream_cb = stream_cb,
.logger.func = slog_func,
});
// run main loop
...
// shutdown sokol-audio
saudio_shutdown();
return 0;
The same code using the push-model
#define BUF_SIZE (32)
int main() {
// init sokol-audio with default params, no callback
saudio_setup(&(saudio_desc){
.logger.func = slog_func,
});
assert(saudio_channels() == 1);
// a small intermediate buffer so we don't need to push
// individual samples, which would be quite inefficient
float buf[BUF_SIZE];
int buf_pos = 0;
uint32_t count = 0;
// push samples from main loop
bool done = false;
while (!done) {
// generate and push audio samples...
int num_frames = saudio_expect();
for (int i = 0; i < num_frames; i++) {
// simple square wave generator
buf[buf_pos++] = (count++ & (1<<3)) ? 0.5f : -0.5f;
if (buf_pos == BUF_SIZE) {
buf_pos = 0;
saudio_push(buf, BUF_SIZE);
}
}
// handle other per-frame stuff...
...
}
// shutdown sokol-audio
saudio_shutdown();
return 0;
}
sokol_fetch.h
Load entire files, or stream data asynchronously over HTTP (emscripten/wasm) or the local filesystem (all native platforms).
Simple C99 example loading a file into a static buffer:
#include "sokol_fetch.h"
#include "sokol_log.h"
static void response_callback(const sfetch_response*);
#define MAX_FILE_SIZE (1024*1024)
static uint8_t buffer[MAX_FILE_SIZE];
// application init
static void init(void) {
...
// setup sokol-fetch with default config:
sfetch_setup(&(sfetch_desc_t){ .logger.func = slog_func });
// start loading a file into a statically allocated buffer:
sfetch_send(&(sfetch_request_t){
.path = "hello_world.txt",
.callback = response_callback
.buffer_ptr = buffer,
.buffer_size = sizeof(buffer)
});
}
// per frame...
static void frame(void) {
...
// need to call sfetch_dowork() once per frame to 'turn the gears':
sfetch_dowork();
...
}
// the response callback is where the interesting stuff happens:
static void response_callback(const sfetch_response_t* response) {
if (response->fetched) {
// data has been loaded into the provided buffer, do something
// with the data...
const void* data = response->buffer_ptr;
uint64_t data_size = response->fetched_size;
}
// the finished flag is set both on success and failure
if (response->failed) {
// oops, something went wrong
switch (response->error_code) {
SFETCH_ERROR_FILE_NOT_FOUND: ...
SFETCH_ERROR_BUFFER_TOO_SMALL: ...
...
}
}
}
// application shutdown
static void shutdown(void) {
...
sfetch_shutdown();
...
}
sokol_time.h:
Simple cross-platform time measurement:
#include "sokol_time.h"
...
/* initialize sokol_time */
stm_setup();
/* take start timestamp */
uint64_t start = stm_now();
...some code to measure...
/* compute elapsed time */
uint64_t elapsed = stm_since(start);
/* convert to time units */
double seconds = stm_sec(elapsed);
double milliseconds = stm_ms(elapsed);
double microseconds = stm_us(elapsed);
double nanoseconds = stm_ns(elapsed);
/* difference between 2 time stamps */
uint64_t start = stm_now();
...
uint64_t end = stm_now();
uint64_t elapsed = stm_diff(end, start);
/* compute a 'lap time' (e.g. for fps) */
uint64_t last_time = 0;
while (!done) {
...render something...
double frame_time_ms = stm_ms(stm_laptime(&last_time));
}
sokol_args.h
Unified argument parsing for web and native apps. Uses argc/argv on native platforms and the URL query string on the web.
Example URL with one arg:
https://floooh.github.io/tiny8bit/kc85.html?type=kc85_4
The same as command line app:
kc85 type=kc85_4
Parsed like this:
#include "sokol_args.h"
int main(int argc, char* argv[]) {
sargs_setup(&(sargs_desc){ .argc=argc, .argv=argv });
if (sargs_exists("type")) {
if (sargs_equals("type", "kc85_4")) {
// start as KC85/4
}
else if (sargs_equals("type", "kc85_3")) {
// start as KC85/3
}
else {
// start as KC85/2
}
}
sargs_shutdown();
return 0;
}
See the sokol_args.h header for a more complete documentation, and the Tiny Emulators for more interesting usage examples.