egldisplay: Support headless OpenGL via EGL when compiled without X11

See #557

makepanda/makepanda.py

@@ -2361,6 +2361,9 @@ def WriteConfigSettings():
         if int(platform.mac_ver()[0][3]) <= 4:
             dtool_config["PHAVE_UCONTEXT_H"] = 'UNDEF'
 
+    if PkgSkip("X11"):
+        dtool_config["HAVE_GLX"] = 'UNDEF'
+
     if (GetTarget() == "freebsd"):
         dtool_config["IS_LINUX"] = 'UNDEF'
         dtool_config["HAVE_VIDEO4LINUX"] = 'UNDEF'
@@ -4494,6 +4497,25 @@ if (GetTarget() == 'windows' and PkgSkip("GL")==0):
 # DIRECTORY: panda/src/egldisplay/
 #
 
+# If we're not compiling with any windowing system at all, but we do have EGL,
+# we can use that to create a headless libpandagl instead.
+if not PkgSkip("EGL") and not PkgSkip("GL") and PkgSkip("X11") and GetTarget() not in ('windows', 'darwin'):
+  DefSymbol('EGL', 'HAVE_EGL', '')
+  OPTS=['DIR:panda/src/egldisplay', 'DIR:panda/src/glstuff', 'BUILDING:PANDAGL', 'GL', 'EGL']
+  TargetAdd('pandagl_egldisplay_composite1.obj', opts=OPTS, input='p3egldisplay_composite1.cxx')
+  OPTS=['DIR:panda/metalibs/pandagl', 'BUILDING:PANDAGL', 'GL', 'EGL']
+  TargetAdd('pandagl_pandagl.obj', opts=OPTS, input='pandagl.cxx')
+  TargetAdd('libpandagl.dll', input='pandagl_pandagl.obj')
+  TargetAdd('libpandagl.dll', input='p3glgsg_config_glgsg.obj')
+  TargetAdd('libpandagl.dll', input='p3glgsg_glgsg.obj')
+  TargetAdd('libpandagl.dll', input='pandagl_egldisplay_composite1.obj')
+  TargetAdd('libpandagl.dll', input=COMMON_PANDA_LIBS)
+  TargetAdd('libpandagl.dll', opts=['MODULE', 'GL', 'EGL', 'CGGL'])
+
+#
+# DIRECTORY: panda/src/egldisplay/
+#
+
 if (PkgSkip("EGL")==0 and PkgSkip("GLES")==0):
   DefSymbol('GLES', 'OPENGLES_1', '')
   OPTS=['DIR:panda/src/egldisplay', 'DIR:panda/src/glstuff', 'BUILDING:PANDAGLES',  'GLES', 'EGL']

panda/metalibs/pandagl/pandagl.cxx

@@ -23,8 +23,13 @@
 #include "glxGraphicsPipe.h"
 #endif
 
-#if !defined(HAVE_WGL) && !defined(HAVE_COCOA) && !defined(HAVE_GLX)
-#error One of HAVE_WGL, HAVE_COCOA or HAVE_GLX must be defined when compiling pandagl!
+#if defined(HAVE_EGL) && !defined(HAVE_X11)
+#include "config_egldisplay.h"
+#include "eglGraphicsPipe.h"
+#endif
+
+#if !defined(HAVE_WGL) && !defined(HAVE_COCOA) && !defined(HAVE_GLX) && !defined(HAVE_EGL)
+#error One of HAVE_WGL, HAVE_COCOA, HAVE_GLX or HAVE_EGL must be defined when compiling pandagl!
 #endif
 
 /**
@@ -45,9 +50,13 @@ init_libpandagl() {
   init_libcocoadisplay();
 #endif
 
-#ifdef IS_LINUX
+#ifdef HAVE_GLX
   init_libglxdisplay();
 #endif
+
+#if defined(HAVE_EGL) && !defined(HAVE_X11)
+  init_libegldisplay();
+#endif
 }
 
 /**
@@ -68,5 +77,9 @@ get_pipe_type_pandagl() {
   return glxGraphicsPipe::get_class_type().get_index();
 #endif
 
+#if defined(HAVE_EGL) && !defined(HAVE_X11)
+  return eglGraphicsPipe::get_class_type().get_index();
+#endif
+
   return 0;
 }

panda/src/egldisplay/config_egldisplay.cxx

@@ -19,8 +19,8 @@
 #include "dconfig.h"
 #include "pandaSystem.h"
 
-#if !defined(CPPPARSER) && !defined(LINK_ALL_STATIC) && !defined(BUILDING_PANDAGLES) && !defined(BUILDING_PANDAGLES2)
-  #error Buildsystem error: BUILDING_PANDAGLES(2) not defined
+#if !defined(CPPPARSER) && !defined(LINK_ALL_STATIC) && !defined(BUILDING_PANDAGLES) && !defined(BUILDING_PANDAGLES2) && !defined(BUILDING_PANDAGL)
+  #error Buildsystem error: BUILDING_PANDAGL(ES(2)) not defined
 #endif
 
 Configure(config_egldisplay);
@@ -57,8 +57,10 @@ init_libegldisplay() {
   PandaSystem *ps = PandaSystem::get_global_ptr();
 #ifdef OPENGLES_2
   ps->set_system_tag("OpenGL ES 2", "window_system", "EGL");
-#else
+#elif defined(OPENGLES_1)
   ps->set_system_tag("OpenGL ES", "window_system", "EGL");
+#else
+  ps->set_system_tag("OpenGL", "window_system", "EGL");
 #endif
 }
 

panda/src/egldisplay/config_egldisplay.h

@@ -23,20 +23,22 @@
 #if defined(OPENGLES_1) && defined(OPENGLES_2)
   #error OPENGLES_1 and OPENGLES_2 cannot be defined at the same time!
 #endif
-#if !defined(OPENGLES_1) && !defined(OPENGLES_2)
-  #error Either OPENGLES_1 or OPENGLES_2 must be defined when compiling egldisplay!
-#endif
 
 #ifdef OPENGLES_2
   NotifyCategoryDecl(egldisplay, EXPCL_PANDAGLES2, EXPTP_PANDAGLES2);
 
   extern EXPCL_PANDAGLES2 void init_libegldisplay();
   extern EXPCL_PANDAGLES2 const std::string get_egl_error_string(int error);
-#else
+#elif defined(OPENGLES_1)
   NotifyCategoryDecl(egldisplay, EXPCL_PANDAGLES, EXPTP_PANDAGLES);
 
   extern EXPCL_PANDAGLES void init_libegldisplay();
   extern EXPCL_PANDAGLES const std::string get_egl_error_string(int error);
+#else
+  NotifyCategoryDecl(egldisplay, EXPCL_PANDAGL, EXPTP_PANDAGL);
+
+  extern EXPCL_PANDAGL void init_libegldisplay();
+  extern EXPCL_PANDAGL const std::string get_egl_error_string(int error);
 #endif
 
 #endif

panda/src/egldisplay/eglGraphicsPipe.cxx

@@ -41,10 +41,17 @@ eglGraphicsPipe() {
     return;
   }
 
+#if defined(OPENGLES_1) || defined(OPENGLES_2)
   if (!eglBindAPI(EGL_OPENGL_ES_API)) {
     egldisplay_cat.error()
       << "Couldn't bind EGL to the OpenGL ES API: "
       << get_egl_error_string(eglGetError()) << "\n";
+#else
+  if (!eglBindAPI(EGL_OPENGL_API)) {
+    egldisplay_cat.error()
+      << "Couldn't bind EGL to the OpenGL API: "
+      << get_egl_error_string(eglGetError()) << "\n";
+#endif
     _is_valid = false;
     return;
   }
@@ -74,7 +81,11 @@ eglGraphicsPipe::
  */
 std::string eglGraphicsPipe::
 get_interface_name() const {
+#if defined(OPENGLES_1) || defined(OPENGLES_2)
   return "OpenGL ES";
+#else
+  return "OpenGL";
+#endif
 }
 
 /**
@@ -143,7 +154,7 @@ make_output(const std::string &name,
 #endif
   }
 
-  // Second thing to try: a GLES(2)GraphicsBuffer
+  // Second thing to try: a GL(ES(2))GraphicsBuffer
   if (retry == 1) {
     if ((host==0)||
   // (!gl_support_fbo)||
@@ -174,9 +185,12 @@ make_output(const std::string &name,
 #ifdef OPENGLES_2
     return new GLES2GraphicsBuffer(engine, this, name, fb_prop, win_prop,
                                   flags, gsg, host);
-#else
+#elif defined(OPENGLES_1)
     return new GLESGraphicsBuffer(engine, this, name, fb_prop, win_prop,
                                   flags, gsg, host);
+#else
+    return new GLGraphicsBuffer(engine, this, name, fb_prop, win_prop,
+                                flags, gsg, host);
 #endif
   }
 

panda/src/egldisplay/eglGraphicsPipe.h

@@ -32,11 +32,16 @@ typedef GraphicsPipe BaseGraphicsPipe;
   #define NativeDisplayType EGLNativeDisplayType
   #define NativePixmapType EGLNativePixmapType
   #define NativeWindowType EGLNativeWindowType
-#else
+#elif defined(OPENGLES_1)
   #include "glesgsg.h"
   #include "pre_x11_include.h"
   #include <GLES/egl.h>
   #include "post_x11_include.h"
+#else
+  #include "glgsg.h"
+  #include "pre_x11_include.h"
+  #include <EGL/egl.h>
+  #include "post_x11_include.h"
 #endif
 
 class FrameBufferProperties;

panda/src/egldisplay/eglGraphicsStateGuardian.cxx

@@ -25,11 +25,7 @@ TypeHandle eglGraphicsStateGuardian::_type_handle;
 eglGraphicsStateGuardian::
 eglGraphicsStateGuardian(GraphicsEngine *engine, GraphicsPipe *pipe,
        eglGraphicsStateGuardian *share_with) :
-#ifdef OPENGLES_2
-  GLES2GraphicsStateGuardian(engine, pipe)
-#else
-  GLESGraphicsStateGuardian(engine, pipe)
-#endif
+  BaseGraphicsStateGuardian(engine, pipe)
 {
   _share_context=0;
   _context=0;
@@ -128,11 +124,12 @@ choose_pixel_format(const FrameBufferProperties &properties,
   _fbprops.clear();
 
   int attrib_list[] = {
-#ifdef OPENGLES_1
+#if defined(OPENGLES_1)
     EGL_RENDERABLE_TYPE, EGL_OPENGL_ES_BIT,
-#endif
-#ifdef OPENGLES_2
+#elif defined(OPENGLES_2)
     EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+#else
+    EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
 #endif
     EGL_SURFACE_TYPE, need_window ? EGL_WINDOW_BIT : EGL_DONT_CARE,
     EGL_NONE
@@ -204,12 +201,36 @@ choose_pixel_format(const FrameBufferProperties &properties,
     egldisplay_cat.debug()
       << "Chosen config " << best_result << ": " << best_props << "\n";
     _fbconfig = configs[best_result];
+
+    EGLint attribs[32];
+    int n = 0;
+
 #ifdef OPENGLES_2
-    EGLint context_attribs[] = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE};
-    _context = eglCreateContext(_egl_display, _fbconfig, _share_context, context_attribs);
-#else
-    _context = eglCreateContext(_egl_display, _fbconfig, _share_context, nullptr);
+    attribs[n++] = EGL_CONTEXT_CLIENT_VERSION;
+    attribs[n++] = 2;
+#elif defined(OPENGLES_1)
+#else  // Regular OpenGL
+    if (gl_version.get_num_words() > 0) {
+      attribs[n++] = EGL_CONTEXT_MAJOR_VERSION;
+      attribs[n++] = gl_version[0];
+      if (gl_version.get_num_words() > 1) {
+        attribs[n++] = EGL_CONTEXT_MINOR_VERSION;
+        attribs[n++] = gl_version[1];
+      }
+    }
+    if (gl_debug) {
+      attribs[n++] = EGL_CONTEXT_OPENGL_DEBUG;
+      attribs[n++] = EGL_TRUE;
+    }
+    if (gl_forward_compatible) {
+      attribs[n++] = EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE;
+      attribs[n++] = EGL_TRUE;
+    }
 #endif
+    attribs[n] = EGL_NONE;
+
+    _context = eglCreateContext(_egl_display, _fbconfig, _share_context, (n > 0) ? attribs : nullptr);
+
     int err = eglGetError();
     if (_context && err == EGL_SUCCESS) {
 #ifdef HAVE_X11
@@ -243,11 +264,7 @@ choose_pixel_format(const FrameBufferProperties &properties,
  */
 void eglGraphicsStateGuardian::
 reset() {
-#ifdef OPENGLES_2
-  GLES2GraphicsStateGuardian::reset();
-#else
-  GLESGraphicsStateGuardian::reset();
-#endif
+  BaseGraphicsStateGuardian::reset();
 
   if (_gl_renderer == "Software Rasterizer") {
     _fbprops.set_force_software(1);
@@ -282,11 +299,7 @@ gl_flush() const {
   // This call requires synchronization with X.
   LightReMutexHolder holder(eglGraphicsPipe::_x_mutex);
 #endif
-#ifdef OPENGLES_2
-  GLES2GraphicsStateGuardian::gl_flush();
-#else
-  GLESGraphicsStateGuardian::gl_flush();
-#endif
+  BaseGraphicsStateGuardian::gl_flush();
 }
 
 /**
@@ -298,11 +311,7 @@ gl_get_error() const {
   // This call requires synchronization with X.
   LightReMutexHolder holder(eglGraphicsPipe::_x_mutex);
 #endif
-#ifdef OPENGLES_2
-  return GLES2GraphicsStateGuardian::gl_get_error();
-#else
-  return GLESGraphicsStateGuardian::gl_get_error();
-#endif
+  return BaseGraphicsStateGuardian::gl_get_error();
 }
 
 /**
@@ -310,11 +319,7 @@ gl_get_error() const {
  */
 void eglGraphicsStateGuardian::
 query_gl_version() {
-#ifdef OPENGLES_2
-  GLES2GraphicsStateGuardian::query_gl_version();
-#else
-  GLESGraphicsStateGuardian::query_gl_version();
-#endif
+  BaseGraphicsStateGuardian::query_gl_version();
 
   // Calling eglInitialize on an already-initialized display will just provide
   // us the version numbers.
@@ -329,9 +334,12 @@ query_gl_version() {
 #ifdef OPENGLES_2
   if (gles2gsg_cat.is_debug()) {
     gles2gsg_cat.debug()
-#else
+#elif defined(OPENGLES_1)
   if (glesgsg_cat.is_debug()) {
     glesgsg_cat.debug()
+#else
+  if (glgsg_cat.is_debug()) {
+    glgsg_cat.debug()
 #endif
       << "EGL_VERSION = " << _egl_version_major << "." << _egl_version_minor
       << "\n";

panda/src/egldisplay/eglGraphicsStateGuardian.h

@@ -21,15 +21,19 @@
 #include "get_x11.h"
 #endif
 
+#ifdef OPENGLES_2
+typedef GLES2GraphicsStateGuardian BaseGraphicsStateGuardian;
+#elif defined(OPENGLES_1)
+typedef GLESGraphicsStateGuardian BaseGraphicsStateGuardian;
+#else
+typedef GLGraphicsStateGuardian BaseGraphicsStateGuardian;
+#endif
+
 /**
  * A tiny specialization on GLESGraphicsStateGuardian to add some egl-specific
  * information.
  */
-#ifdef OPENGLES_2
-class eglGraphicsStateGuardian : public GLES2GraphicsStateGuardian {
-#else
-class eglGraphicsStateGuardian : public GLESGraphicsStateGuardian {
-#endif
+class eglGraphicsStateGuardian : public BaseGraphicsStateGuardian {
 public:
   INLINE const FrameBufferProperties &get_fb_properties() const;
   void get_properties(FrameBufferProperties &properties,
@@ -73,15 +77,9 @@ public:
     return _type_handle;
   }
   static void init_type() {
-#ifdef OPENGLES_2
-    GLES2GraphicsStateGuardian::init_type();
+    BaseGraphicsStateGuardian::init_type();
     register_type(_type_handle, "eglGraphicsStateGuardian",
-                  GLES2GraphicsStateGuardian::get_class_type());
-#else
-    GLESGraphicsStateGuardian::init_type();
-    register_type(_type_handle, "eglGraphicsStateGuardian",
-                  GLESGraphicsStateGuardian::get_class_type());
-#endif
+                  BaseGraphicsStateGuardian::get_class_type());
   }
   virtual TypeHandle get_type() const {
     return get_class_type();