prototype a new headless egl context

glcontext/headless.cpp

@@ -0,0 +1,107 @@
+#include <Python.h>
+
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+
+int num_devices;
+EGLDeviceEXT devices[64];
+
+EGLContext context;
+EGLDisplay display;
+EGLConfig config;
+
+PyObject * meth_devices(PyObject * self) {
+    PFNEGLQUERYDEVICESEXTPROC eglQueryDevicesEXT = (PFNEGLQUERYDEVICESEXTPROC)eglGetProcAddress("eglQueryDevicesEXT");
+    PFNEGLQUERYDEVICESTRINGEXTPROC eglQueryDeviceStringEXT = (PFNEGLQUERYDEVICESTRINGEXTPROC)eglGetProcAddress("eglQueryDeviceStringEXT");
+
+    if (!eglQueryDevicesEXT(0, NULL, &num_devices)) {
+        return NULL;
+    }
+
+    if (!eglQueryDevicesEXT(num_devices, devices, &num_devices)) {
+        return NULL;
+    }
+
+    PyObject * res = PyList_New(num_devices);
+    for (int i = 0; i < num_devices; ++i) {
+        const char * egl_extensions = eglQueryDeviceStringEXT(devices[i], EGL_EXTENSIONS);
+        PyObject * temp = PyUnicode_FromString(egl_extensions ? egl_extensions : "");
+        PyObject * extensions = PyObject_CallMethod(temp, "split", NULL);
+        Py_DECREF(temp);
+        PyList_SetItem(res, i, Py_BuildValue("{sisN}", "device", i, "extensions", extensions));
+    }
+    return res;
+}
+
+PyObject * meth_init(PyObject * self, PyObject * args, PyObject * kwargs) {
+    const char * keywords[] = {"device", NULL};
+
+    int device = 0;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "i", (char **)keywords, &device)) {
+        return NULL;
+    }
+
+    if (device > num_devices) {
+        return NULL;
+    }
+
+    display = eglGetPlatformDisplay(EGL_PLATFORM_DEVICE_EXT, devices[device], 0);
+    if (display == EGL_NO_DISPLAY) {
+        return NULL;
+    }
+
+    if (!eglInitialize(display, NULL, NULL)) {
+        return NULL;
+    }
+
+    int config_attribs[] = {
+        EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
+        EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
+        EGL_NONE,
+    };
+
+    int num_configs = 0;
+    if (!eglChooseConfig(display, config_attribs, &config, 1, &num_configs)) {
+        return NULL;
+    }
+
+    if (!eglBindAPI(EGL_OPENGL_API)) {
+        return NULL;
+    }
+
+    int context_attribs[] = {
+        EGL_CONTEXT_OPENGL_PROFILE_MASK, EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT,
+        EGL_NONE,
+    };
+
+    context = eglCreateContext(display, config, EGL_NO_CONTEXT, context_attribs);
+    if (!context) {
+        return NULL;
+    }
+
+    eglMakeCurrent(display, EGL_NO_SURFACE, EGL_NO_SURFACE, context);
+    Py_RETURN_NONE;
+}
+
+PyObject * meth_load_opengl_function(PyObject * self, PyObject * arg) {
+    if (!PyUnicode_CheckExact(arg)) {
+        return NULL;
+    }
+    const char * name = PyUnicode_AsUTF8(arg);
+    return PyLong_FromVoidPtr((void *)eglGetProcAddress(name));
+}
+
+PyMethodDef module_methods[] = {
+    {"devices", (PyCFunction)meth_devices, METH_NOARGS},
+    {"init", (PyCFunction)meth_init, METH_VARARGS | METH_KEYWORDS},
+    {"load_opengl_function", (PyCFunction)meth_load_opengl_function, METH_O},
+    {},
+};
+
+PyModuleDef module_def = {PyModuleDef_HEAD_INIT, "headless", NULL, -1, module_methods};
+
+extern "C" PyObject * PyInit_headless() {
+    PyObject * module = PyModule_Create(&module_def);
+    return module;
+}

setup.py

@@ -44,6 +44,12 @@
     libraries=['dl'],
 )
 
+headless = Extension(
+    name='glcontext.headless',
+    sources=['glcontext/headless.cpp'],
+    libraries=['EGL'],
+)
+
 darwin = Extension(
     name='glcontext.darwin',
     sources=['glcontext/darwin.cpp'],
@@ -53,7 +59,7 @@
 
 ext_modules = {
     'windows': [wgl],
-    'linux': [x11, egl],
+    'linux': [x11, egl, headless],
     'darwin': [darwin],
 }
 

test.py

@@ -1,6 +1,15 @@
-import glcontext
+import ctypes
 
-backend = glcontext.default_backend()
-ctx = backend(mode='standalone', glversion=330)  #, libgl='libGL.so.1')
-print(ctx)
-print(ctx.load('glViewport'))
+from glcontext import headless
+
+devices = headless.devices()
+
+headless.init(device=next(x['device'] for x in devices if 'EGL_MESA_device_software' in x['extensions']))
+
+glGetStringPtr = headless.load_opengl_function('glGetString')
+glGetString = ctypes.cast(glGetStringPtr, ctypes.CFUNCTYPE(ctypes.c_char_p, ctypes.c_uint32))
+
+print(glGetString(0x1F00).decode())
+print(glGetString(0x1F01).decode())
+print(glGetString(0x1F02).decode())
+print(glGetString(0x1F03).decode())