Added osmesa "backend" for OpenGL (off-screen) rendering

in gtk port.
This is enabled with --enable-osmesa configure switch and
shouldn't break (or change) anything when the switch is not
used.
If someone feels like porting that to glade port, go ahead...
but there's a number of opengl/gtkglext/etc. issues that will
need to be fixed first.

desmume/configure.ac

@@ -55,6 +55,19 @@ dnl - Check for the OpenGL includes
 AC_CHECK_HEADERS([GL/gl.h])
 AC_CHECK_HEADERS([GL/glu.h])
 
+dnl - if --enable-osmesa is used, check for it
+AC_ARG_ENABLE(osmesa,
+              [AC_HELP_STRING(--enable-osmesa, use off-screen mesa)],
+              [
+		if test "x$enableval" = "xyes" ; then
+			AC_CHECK_LIB(OSMesa, main,[
+				useosmesa=yes
+				AC_DEFINE(HAVE_LIBOSMESA)
+				LIBS="-lOSMesa $LIBS"
+			])
+		fi
+		])
+
 dnl - Check for GTK and/or libglade
 GLIB_VER=2.8
 GTK_VER=2.6
@@ -79,12 +92,14 @@ AC_PROVIDE_IFELSE([PKG_PROG_PKG_CONFIG], [
     AC_SUBST(GTK_CFLAGS)
     AC_SUBST(GTK_LIBS)
 
+    if test ! "x$useosmesa" = "xyes" ; then
     PKG_CHECK_MODULES(GTKGLEXT,
                       "gtkglext-1.0",
                       HAVE_GTKGLEXT=yes,
                       HAVE_GTKGLEXT=no)
     AC_SUBST(GTKGLEXT_CFLAGS)
     AC_SUBST(GTKGLEXT_LIBS)
+    fi
 
     PKG_CHECK_MODULES(GTHREAD,
                       "gthread-2.0",
@@ -128,6 +143,9 @@ if test "x$HAVE_SDL" = "xyes"; then
     UI_DIR="gtk $UI_DIR"
   fi
 
+  dnl - the glade port has a weird relation to gtkglext and doesn't
+  dnl - works yet with osmesa, feel free to fix it :)
+  if test ! "x$useosmesa" = "xyes" ; then
   if test "x$HAVE_LIBGLADE" = "xyes"; then
     AC_PROVIDE_IFELSE([IT_PROG_INTLTOOL],[
       # libglade requires SDL too
@@ -147,12 +165,13 @@ if test "x$HAVE_SDL" = "xyes"; then
       echo "WARNING: intltool and/or gettext are not available therefore the gtk-glade interface won't be installed. The gtk-glade UI requires intltool and gettext."
     ])
   fi
+  fi
 fi
 
 dnl Set compiler library flags per target.
 case $target in
   *linux* | *bsd*)
-    LIBS="$LIBS -lGL -lGLU"
+    LIBS="$LIBS -lGLU"
     ;;
   *mingw*)
     LIBS="$LIBS -ldxguid -ldxerr8 -ldsound -lopengl32 -lws2_32 -mwindows"

desmume/src/OGLRender.cpp

@@ -307,6 +307,10 @@ static void createShaders()
 {
 	hasShaders = true;
 
+#ifdef HAVE_LIBOSMESA
+	NOSHADERS(1);
+#endif
+
 	if (glCreateShader == NULL ||  //use ==NULL instead of !func to avoid always true warnings for some systems
 		glShaderSource == NULL ||
 		glCompileShader == NULL ||
@@ -419,7 +423,11 @@ static char OGLInit(void)
 	INITOGLEXT(PFNGLGETPROGRAMIVPROC,glGetProgramiv)
 	INITOGLEXT(PFNGLGETPROGRAMINFOLOGPROC,glGetProgramInfoLog)
 	INITOGLEXT(PFNGLVALIDATEPROGRAMPROC,glValidateProgram)
+#ifdef HAVE_LIBOSMESA
+	glBlendFuncSeparateEXT = NULL;
+#else
 	INITOGLEXT(PFNGLBLENDFUNCSEPARATEEXTPROC,glBlendFuncSeparateEXT)
+#endif
 	INITOGLEXT(PFNGLGETUNIFORMLOCATIONPROC,glGetUniformLocation)
 	INITOGLEXT(PFNGLUNIFORM1IPROC,glUniform1i)
 #endif

desmume/src/gtk/Makefile.am

@@ -16,6 +16,7 @@ desmume_SOURCES = \
 	../sndsdl.cpp \
 	../ctrlssdl.h ../ctrlssdl.cpp \
 	gdk_3Demu.cpp gdk_3Demu.h \
+	osmesa_3Demu.cpp osmesa_3Demu.h \
 	 main.cpp
 desmume_LDADD = ../libdesmume.a \
 	$(SDL_LIBS) $(GTK_LIBS) $(GTKGLEXT_LIBS) $(GTHREAD_LIBS)

desmume/src/gtk/main.cpp

@@ -43,13 +43,18 @@
 #include "gdbstub.h"
 #endif
 
-#ifdef GTKGLEXT_AVAILABLE
+#if defined(GTKGLEXT_AVAILABLE) || defined(HAVE_LIBOSMESA)
 #include <GL/gl.h>
 #include <GL/glu.h>
-#include <gtk/gtkgl.h>
 #include "OGLRender.h"
+#ifdef GTKGLEXT_AVAILABLE
+#include <gtk/gtkgl.h>
 #include "gdk_3Demu.h"
 #endif
+#ifdef HAVE_LIBOSMESA
+#include "osmesa_3Demu.h"
+#endif
+#endif
 
 #include "DeSmuME.xpm"
 
@@ -98,7 +103,7 @@ NULL
 
 GPU3DInterface *core3DList[] = {
   &gpu3DNull
-#ifdef GTKGLEXT_AVAILABLE
+#if defined(GTKGLEXT_AVAILABLE) || defined(HAVE_LIBOSMESA)
   ,
   &gpu3Dgl
 #endif
@@ -1895,10 +1900,14 @@ common_gtk_main( struct configured_features *my_config)
         {
           int use_null_3d = my_config->disable_3d;
 
-#ifdef GTKGLEXT_AVAILABLE
+#if defined(GTKGLEXT_AVAILABLE) || defined(HAVE_LIBOSMESA)
           if ( !use_null_3d) {
             /* setup the gdk 3D emulation */
+#ifdef GTKGLEXT_AVAILABLE
             if ( init_opengl_gdk_3Demu()) {
+#else
+            if ( init_osmesa_3Demu()) {
+#endif
               NDS_3D_SetDriver ( 1);
 
               if (!gpu3D->NDS_3D_Init ()) {

desmume/src/gtk/osmesa_3Demu.cpp

@@ -0,0 +1,53 @@
+/*  
+    Copyright (C) 2009 Guillaume Duhamel
+
+    This file is part of DeSmuME
+
+    DeSmuME is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DeSmuME is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DeSmuME; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#ifdef HAVE_LIBOSMESA
+#include <GL/osmesa.h>
+#include "../OGLRender.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+static bool osmesa_beginOpenGL(void) {
+  return 1;
+}
+
+static void osmesa_endOpenGL(void) {
+}
+
+static bool osmesa_init(void) {
+
+  return true;
+}
+
+int init_osmesa_3Demu(void) {
+  void * buffer;
+  OSMesaContext ctx;
+
+  ctx = OSMesaCreateContext(OSMESA_RGBA, NULL);
+  buffer = malloc(256 * 192 * 4);
+  OSMesaMakeCurrent(ctx, buffer, GL_UNSIGNED_BYTE, 256, 192);
+
+  oglrender_init = osmesa_init;
+  oglrender_beginOpenGL = osmesa_beginOpenGL;
+  oglrender_endOpenGL = osmesa_endOpenGL;
+
+  return 1;
+}
+#endif

desmume/src/gtk/osmesa_3Demu.h

@@ -0,0 +1,23 @@
+/*  
+    Copyright (C) 2009 Guillaume Duhamel
+
+    This file is part of DeSmuME
+
+    DeSmuME is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DeSmuME is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DeSmuME; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#ifdef HAVE_LIBOSMESA
+int init_osmesa_3Demu( void);
+#endif