path: root/src/egl_common.c

#define AL_LOG_SECTION "egl"
#include <al/log.h>
#include <al/macros.h>

#ifdef STELA_API_OPENGL
#include "egl_common.h"

#define STELA_GL_API EGL_OPENGL_API
#define STELA_GLES_API EGL_OPENGL_ES_API

#define STELA_GL_BIT EGL_OPENGL_BIT
#define STELA_GLES2_BIT EGL_OPENGL_ES2_BIT
#define STELA_GLES3_BIT EGL_OPENGL_ES3_BIT

#define STELA_GL_CORE_PROFILE_BIT EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT

#include "gl_versions.h"

PASTE_GL_VERSIONS()
#endif

bool stl_maybe_load_egl(void)
{
#ifdef STELA_USE_GLAD
    s32 egl_version = gladLoaderLoadEGL(NULL);
    if (!egl_version) {
        log_error("Failed to pre-load EGL (glad).");
        return false;
    }
#endif
    return true;
}

bool stl_load_egl(struct stl_egl_global *global)
{
    EGLint major, minor;
    if (!eglInitialize(global->display, &major, &minor)) {
        log_error("Failed to initialize.");
        return false;
    }
    log_debug("eglInitialize()'d version %d.%d.", major, minor);

#ifdef STELA_USE_GLAD
    s32 egl_version = gladLoaderLoadEGL(global->display);
    if (!egl_version) {
        log_error("Failed to load EGL (glad).");
        return false;
    }
    log_debug("Using EGL (glad) version %s.", eglQueryString(global->display, EGL_VERSION));
#else
    log_debug("Using EGL version %s.", eglQueryString(global->display, EGL_VERSION));
#endif

    return true;
}

void stl_terminate_egl(struct stl_egl_global *global)
{
    if (global->display != EGL_NO_DISPLAY) {
        if (!eglTerminate(global->display)) {
            log_warn("Failed to eglTerminate().");
        }
    }
}

// https://gitlab.freedesktop.org/mesa/kmscube/-/blob/master/common.c#L162
static EGLint match_config_to_visual(EGLDisplay display, EGLint visual_id, EGLConfig *configs, EGLint count)
{
    EGLint id;
    for (EGLint i = 0; i < count; i++) {
        if (!eglGetConfigAttrib(display, configs[i], EGL_NATIVE_VISUAL_ID, &id)) {
            continue;
        }
        if (id == visual_id) return i;
    }
    return -1;
}

static bool egl_choose_config(EGLDisplay display, const EGLint *attribs, EGLint visual_id, EGLConfig *config)
{
    EGLint count = 0;
    if (!eglGetConfigs(display, NULL, 0, &count) || count <= 0) {
        log_error("No configs to choose from.");
        return false;
    }

    EGLint matched = 0;
    EGLConfig *configs = (EGLConfig *)al_malloc(count * sizeof(EGLConfig));
    if (!eglChooseConfig(display, attribs, configs, count, &matched) || !matched) {
        log_error("No configs with appropriate attributes.");
        al_free(configs);
        return false;
    }

    EGLint index = visual_id ? match_config_to_visual(display, visual_id, config, matched) : 0;
    if (index != -1) *config = configs[index];
    al_free(configs);

    return index != -1;
}

bool stl_init_egl_context(struct stl_egl *egl, struct stl_egl_global *global, EGLint visual_id, EGLConfig *config)
{
    egl->display = global->display;

    egl->context = EGL_NO_CONTEXT;
    for (u32 i = 0; i < ARRAY_SIZE(stl_gl_vers); i++) {
        const EGLint context_attr_gles[] = {
            EGL_CONTEXT_CLIENT_VERSION, stl_gl_vers[i].major,
            EGL_NONE
        };

        const EGLint context_attr_gl[] = {
#ifdef AL_DEBUG
            EGL_CONTEXT_OPENGL_DEBUG, EGL_TRUE,
#endif
            EGL_CONTEXT_MAJOR_VERSION, stl_gl_vers[i].major,
            EGL_CONTEXT_MINOR_VERSION, stl_gl_vers[i].minor,
            EGL_CONTEXT_OPENGL_PROFILE_MASK, stl_gl_vers[i].profile,
            EGL_NONE
        };

        STELA_LOG_GL_CONTEXT_CREATION(stl_gl_vers[i]);

        const EGLint *context_attr = stl_gl_vers[i].api == STELA_GL_API ?
            context_attr_gl : context_attr_gles;

        eglBindAPI(stl_gl_vers[i].api);

#define STELA_INCLUDE_DEPTH_BUFFER
        const EGLint window_attr[] = {
            EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
            EGL_RED_SIZE, 8,
            EGL_GREEN_SIZE, 8,
            EGL_BLUE_SIZE, 8,
            EGL_ALPHA_SIZE, 8,
#ifdef STELA_INCLUDE_DEPTH_BUFFER
            EGL_DEPTH_SIZE, 24,
            EGL_STENCIL_SIZE, 8,
#else
            EGL_DEPTH_SIZE, 0,
            EGL_STENCIL_SIZE, 0,
#endif
            EGL_RENDERABLE_TYPE, stl_gl_vers[i].type,
            EGL_SAMPLES, 0,
            EGL_NONE
        };

        if (!egl_choose_config(egl->display, window_attr, visual_id, config)) {
            log_error("Failed to choose a display config.");
            continue;
        }


        egl->context = eglCreateContext(egl->display, *config, EGL_NO_CONTEXT, context_attr);

        if (egl->context == EGL_NO_CONTEXT) {
            continue;
        } else {
            break;
        }
    }

    if (egl->context == EGL_NO_CONTEXT) {
        log_error("Failed to create context.");
        return false;
    }

    egl->current = EGL_NO_CONTEXT;
    egl->surface = EGL_NO_SURFACE;

    return true;
}

bool stl_egl_make_current(struct stl_egl *egl)
{
    if (egl->context != egl->current) {
        al_assert(egl->current == EGL_NO_CONTEXT);
        egl->current = egl->context;
        return eglMakeCurrent(egl->display, egl->surface, egl->surface, egl->context);
    }
    return true;
}

void stl_egl_release_current(struct stl_egl *egl)
{
    // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6547
    // libplacebo calls release_current() after swapping buffers. That locks in the
    // current backbuffer size. So, if all that happens for the next frame is:
    //  1. wl_egl_window_resize()
    //  2. resize libplacebo swapchain
    //  3. start frame
    //  4. submit frame
    //  5. swap buffers
    // The frame that is presented will still have the dimensions of the previous backbuffer.
    // We only support 1 context at a time, so this shouldn't be an issue.
    al_assert(egl->context == egl->current);
#if 0
    if (egl->current != EGL_NO_CONTEXT) {
        eglMakeCurrent(egl->display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
        egl->current = EGL_NO_CONTEXT;
    }
#endif
}

void stl_egl_swap_interval(struct stl_egl *egl, EGLint interval)
{
    eglSwapInterval(egl->display, interval);
}

void stl_egl_swap_buffers(struct stl_egl *egl)
{
    eglSwapBuffers(egl->display, egl->surface);
}

bool stl_egl_is_ready(struct stl_egl *egl)
{
    return egl->context != EGL_NO_CONTEXT;
}

void stl_egl_destroy_surface(struct stl_egl *egl)
{
    eglDestroySurface(egl->display, egl->surface);
}

void stl_egl_destroy_context(struct stl_egl *egl)
{
    eglDestroyContext(egl->display, egl->context);
}

#define ERROR_CASE_STR(value) case value: return #value;
static const char *eglGetErrorString(EGLint error)
{
    switch (error) {
    ERROR_CASE_STR(EGL_SUCCESS)
    ERROR_CASE_STR(EGL_NOT_INITIALIZED)
    ERROR_CASE_STR(EGL_BAD_ACCESS)
    ERROR_CASE_STR(EGL_BAD_ALLOC)
    ERROR_CASE_STR(EGL_BAD_ATTRIBUTE)
    ERROR_CASE_STR(EGL_BAD_CONTEXT)
    ERROR_CASE_STR(EGL_BAD_CONFIG)
    ERROR_CASE_STR(EGL_BAD_CURRENT_SURFACE)
    ERROR_CASE_STR(EGL_BAD_DISPLAY)
    ERROR_CASE_STR(EGL_BAD_SURFACE)
    ERROR_CASE_STR(EGL_BAD_MATCH)
    ERROR_CASE_STR(EGL_BAD_PARAMETER)
    ERROR_CASE_STR(EGL_BAD_NATIVE_PIXMAP)
    ERROR_CASE_STR(EGL_BAD_NATIVE_WINDOW)
    ERROR_CASE_STR(EGL_CONTEXT_LOST)
    default: return "Unknown";
    }
}
#undef ERROR_CASE_STR

void stl_egl_check_error()
{
    EGLint error;
    while ((error = eglGetError()) != EGL_SUCCESS) {
        log_error("EGL error %s, %d.", eglGetErrorString(error), error);
    }
}