AnimTestbed/3rdparty/sokol/README.md

# Sokol

[![Build Status](https://github.com/floooh/sokol/workflows/build_and_test/badge.svg)](https://github.com/floooh/sokol/actions)

Simple
[STB-style](https://github.com/nothings/stb/blob/master/docs/stb_howto.txt)
cross-platform libraries for C and C++, written in C.

[**See what's new**](https://github.com/floooh/sokol/blob/master/CHANGELOG.md) (**08-Oct-2021** revisited and cleaned up texture compression support in sokol_gfx.h)

## Examples and Related Projects

- [Live Samples](https://floooh.github.io/sokol-html5/index.html) via WASM ([source](https://github.com/floooh/sokol-samples))

- [Doom Shareware](https://floooh.github.io/doom-sokol/) ported to the Sokol headers ([source](https://github.com/floooh/doom-sokol))

- [LearnOpenGL examples ported to sokol-gfx](https://www.geertarien.com/learnopengl-examples-html5/) by @geertarien (cool stuff!)

- [Dear ImGui starterkit](https://github.com/floooh/cimgui-sokol-starterkit) a self-contained starterkit for writing Dear ImGui apps in C.

- [Tiny 8-bit emulators](https://floooh.github.io/tiny8bit/)

- A 'single-file' [Pacman clone in C99](https://github.com/floooh/pacman.c/), also available in [Zig](https://github.com/floooh/pacman.zig/)

- A [Minigolf game](https://mgerdes.github.io/minigolf.html) ([source](https://github.com/mgerdes/minigolf)).

- ['Dealer's Dungeon'](https://dealers-dungeon.com/demo/) ([lower graphics quality](https://dealers-dungeon.com/demo/?q=3),
[source](https://github.com/bqqbarbhg/spear))

- [Command line tools](https://github.com/floooh/sokol-tools) (shader compiler)

- [How to build without a build system](https://github.com/floooh/sokol-samples#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**](https://github.com/floooh/sokol/blob/master/sokol_gfx.h): 3D-API wrapper (GL + Metal + D3D11)
- [**sokol\_app.h**](https://github.com/floooh/sokol/blob/master/sokol_app.h): app framework wrapper (entry + window + 3D-context + input)
- [**sokol\_time.h**](https://github.com/floooh/sokol/blob/master/sokol_time.h): time measurement
- [**sokol\_audio.h**](https://github.com/floooh/sokol/blob/master/sokol_audio.h): minimal buffer-streaming audio playback
- [**sokol\_fetch.h**](https://github.com/floooh/sokol/blob/master/sokol_fetch.h): asynchronous data streaming from HTTP and local filesystem
- [**sokol\_args.h**](https://github.com/floooh/sokol/blob/master/sokol_args.h): unified cmdline/URL arg parser for web and native apps

## Utility libraries

- [**sokol\_imgui.h**](https://github.com/floooh/sokol/blob/master/util/sokol_imgui.h): sokol_gfx.h rendering backend for [Dear ImGui](https://github.com/ocornut/imgui)
- [**sokol\_nuklear.h**](https://github.com/floooh/sokol/blob/master/util/sokol_nuklear.h): sokol_gfx.h rendering backend for [Nuklear](https://github.com/Immediate-Mode-UI/Nuklear)
- [**sokol\_gl.h**](https://github.com/floooh/sokol/blob/master/util/sokol_gl.h): OpenGL 1.x style immediate-mode rendering API on top of sokol_gfx.h
- [**sokol\_fontstash.h**](https://github.com/floooh/sokol/blob/master/util/sokol_fontstash.h): sokol_gl.h rendering backend for [fontstash](https://github.com/memononen/fontstash)
- [**sokol\_gfx\_imgui.h**](https://github.com/floooh/sokol/blob/master/util/sokol_gfx_imgui.h): debug-inspection UI for sokol_gfx.h (implemented with Dear ImGui)
- [**sokol\_debugtext.h**](https://github.com/floooh/sokol/blob/master/util/sokol_debugtext.h): a simple text renderer using vintage home computer fonts
- [**sokol\_memtrack.h**](https://github.com/floooh/sokol/blob/master/util/sokol_memtrack.h): easily track memory allocations in sokol headers
- [**sokol\_shape.h**](https://github.com/floooh/sokol/blob/master/util/sokol_shape.h): generate simple shapes and plug them into sokol-gfx resource creation structs
- [**sokol\_color.h**](https://github.com/floooh/sokol/blob/master/util/sokol_color.h): X11 style color constants and functions for creating sg_color objects

## 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](http://floooh.github.io/2017/07/29/sokol-gfx-tour.html)

# 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](https://github.com/floooh/sokol-tools/blob/master/docs/sokol-shdc.md)

A triangle in C99 with GLFW:

```c
#define SOKOL_IMPL
#define SOKOL_GLCORE33
#include "sokol_gfx.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){0});

    /* 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):

```c
#include "sokol_gfx.h"
#include "sokol_app.h"
#include "sokol_glue.h"

sg_pass_action pass_action;

void init(void) {
    sg_setup(&(sg_desc){
        .context = sapp_sgcontext()
    });
    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",
    };
}
```

# 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:
    1. directly fill backend audio buffer from your callback function running in the audio thread
    2. 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:

```c
// 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
    });

    // run main loop
    ...

    // shutdown sokol-audio
    saudio_shutdown();
    return 0;
```

The same code using the push-model

```c
#define BUF_SIZE (32)
int main() {
    // init sokol-audio with default params, no callback
    saudio_setup(&(saudio_desc){0});
    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:

```c
#include "sokol_fetch.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){0});

    // 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:

```c
#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:

```c
#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](https://floooh.github.io/tiny8bit/) for more interesting usage examples.