[common] added new sysinfo unit and multisample query support

Based on @rLink234's work in 4ac781b4516678b6c59d9ecf4a61df64a01ec8c1

VERSION

@@ -1 +1 @@
-a12-217-gf946117dac+1
+a12-219-g3585e02993+1

common/CMakeLists.txt

@@ -5,16 +5,28 @@ include_directories(
 	${PROJECT_SOURCE_DIR}/include
 )
 
-set(SOURCES
+set(COMMON_SOURCES
   src/stringutils.c
   src/stringlist.c
   src/option.c
 )
 
+set(LINUX_SOURCES
+  src/crash.linux.c
+  src/sysinfo.linux.c
+)
+
+set(WINOWS_SOURCES
+  src/crash.windows.c
+  src/sysinfo.windows.c
+)
+
 if(WIN32)
-  add_library(lg_common STATIC src/crash.windows.c ${SOURCES})
+  set(SOURCES ${COMMON_SOURCES} ${WINDOWS_SOURCES})
+  add_library(lg_common STATIC ${SOURCES})
 else()
-  add_library(lg_common STATIC src/crash.linux.c ${SOURCES})
+  set(SOURCES ${COMMON_SOURCES} ${LINUX_SOURCES})
+  add_library(lg_common STATIC ${SOURCES})
   target_link_libraries(lg_common bfd)
 endif()
 

common/include/common/sysinfo.h

@@ -0,0 +1,21 @@
+/*
+KVMGFX Client - A KVM Client for VGA Passthrough
+Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program 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.
+
+This program 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
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+// returns the maximum number of multisamples supported by the system
+int sysinfo_gfx_max_multisample();

common/src/sysinfo.linux.c

@@ -0,0 +1,64 @@
+/*
+KVMGFX Client - A KVM Client for VGA Passthrough
+Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program 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.
+
+This program 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
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <GL/glx.h>
+
+int sysinfo_gfx_max_multisample()
+{
+  Display * dpy = XOpenDisplay(NULL);
+  if (!dpy)
+    return -1;
+
+  XVisualInfo queryTemplate;
+  queryTemplate.screen = 0;
+
+  int visualCount;
+  int maxSamples = -1;
+  XVisualInfo * visuals = XGetVisualInfo(dpy, VisualScreenMask, &queryTemplate, &visualCount);
+
+  for (int i = 0; i < visualCount; i++)
+  {
+    XVisualInfo * visual = &visuals[i];
+
+    int res, supportsGL;
+    // Some GLX visuals do not use GL, and these must be ignored in our search.
+    if ((res = glXGetConfig(dpy, visual, GLX_USE_GL, &supportsGL)) != 0 || !supportsGL)
+      continue;
+
+    int sampleBuffers, samples;
+    if ((res = glXGetConfig(dpy, visual, GLX_SAMPLE_BUFFERS, &sampleBuffers)) != 0)
+      continue;
+
+    // Will be 1 if this visual supports multisampling
+    if (sampleBuffers != 1)
+      continue;
+
+    if ((res = glXGetConfig(dpy, visual, GLX_SAMPLES, &samples)) != 0)
+      continue;
+
+    // Track the largest number of samples supported
+    if (samples > maxSamples)
+      maxSamples = samples;
+
+  }
+
+  XCloseDisplay(dpy);
+
+  return maxSamples;
+}

common/src/sysinfo.windows.c

@@ -0,0 +1,24 @@
+/*
+KVMGFX Client - A KVM Client for VGA Passthrough
+Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program 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.
+
+This program 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
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+int sysinfo_gfx_max_multisample()
+{
+  //FIXME: Implement this
+  return 4;
+}