render/egl: add wlr_egl_get_{context,display}

This allows compositors to integrate with the wlroots GLES2
renderer, if they need to perform custom GL rendering.

include/wlr/render/egl.h

@@ -70,6 +70,22 @@ struct wlr_egl {
 struct wlr_egl *wlr_egl_create_with_context(EGLDisplay display,
 	EGLContext context);
 
+/**
+ * Get the EGL display used by the struct wlr_egl.
+ *
+ * This is typically used by compositors which need to perform custom OpenGL
+ * operations.
+ */
+EGLDisplay wlr_egl_get_display(struct wlr_egl *egl);
+
+/**
+ * Get the EGL context used by the struct wlr_egl.
+ *
+ * This is typically used by compositors which need to perform custom OpenGL
+ * operations.
+ */
+EGLContext wlr_egl_get_context(struct wlr_egl *egl);
+
 /**
  * Make the EGL context current.
  *

render/egl.c

@@ -583,6 +583,14 @@ void wlr_egl_destroy(struct wlr_egl *egl) {
 	free(egl);
 }
 
+EGLDisplay wlr_egl_get_display(struct wlr_egl *egl) {
+	return egl->display;
+}
+
+EGLContext wlr_egl_get_context(struct wlr_egl *egl) {
+	return egl->context;
+}
+
 bool wlr_egl_destroy_image(struct wlr_egl *egl, EGLImage image) {
 	if (!egl->exts.KHR_image_base) {
 		return false;