From 10bed7ca586eaecee20524c582decacef7a3a1d1 Mon Sep 17 00:00:00 2001
From: Utkarsh Ayachit <utkarsh.ayachit@kitware.com>
Date: Wed, 6 Jul 2016 15:26:16 -0400
Subject: [PATCH 1/2] Create correct OSMesa context.

Bringing in changes from vtkOSOpenGLRenderWindow to
vtkXOpenGLRenderWindow to create correct OSMesa context for OpenGL2
backend.
---
 Rendering/OpenGL2/vtkXOpenGLRenderWindow.cxx | 37 ++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/Rendering/OpenGL2/vtkXOpenGLRenderWindow.cxx b/Rendering/OpenGL2/vtkXOpenGLRenderWindow.cxx
index fb741a3d40a..728b1b20f0f 100644
--- a/Rendering/OpenGL2/vtkXOpenGLRenderWindow.cxx
+++ b/Rendering/OpenGL2/vtkXOpenGLRenderWindow.cxx
@@ -30,10 +30,25 @@ typedef ptrdiff_t GLintptr;
 typedef ptrdiff_t GLsizeiptr;
 #include "GL/glx.h"
 
+
+#ifndef GLAPI
+#define GLAPI extern
+#endif
+
+#ifndef GLAPIENTRY
+#define GLAPIENTRY
+#endif
+
+#ifndef APIENTRY
+#define APIENTRY GLAPIENTRY
+#endif
+
 #include "vtkToolkits.h"
 
 #ifdef VTK_USE_OSMESA
 #include <GL/osmesa.h>
+
+typedef OSMesaContext GLAPIENTRY (*OSMesaCreateContextAttribs_func)( const int *attribList, OSMesaContext sharelist );
 #endif
 
 #include "vtkCommand.h"
@@ -769,6 +784,28 @@ void vtkXOpenGLRenderWindow::CreateOffScreenWindow(int width, int height)
       this->Size[1] = height;
       this->OwnWindow = 1;
       }
+
+#if (OSMESA_MAJOR_VERSION * 100 + OSMESA_MINOR_VERSION >= 1102) && defined(OSMESA_CONTEXT_MAJOR_VERSION)
+    static const int attribs[] = {
+       OSMESA_FORMAT, OSMESA_RGBA,
+       OSMESA_DEPTH_BITS, 32,
+       OSMESA_STENCIL_BITS, 0,
+       OSMESA_ACCUM_BITS, 0,
+       OSMESA_PROFILE, OSMESA_CORE_PROFILE,
+       OSMESA_CONTEXT_MAJOR_VERSION, 3,
+       OSMESA_CONTEXT_MINOR_VERSION, 2,
+       0 };
+
+    OSMesaCreateContextAttribs_func OSMesaCreateContextAttribs =
+       (OSMesaCreateContextAttribs_func)
+       OSMesaGetProcAddress("OSMesaCreateContextAttribs");
+
+    if (OSMesaCreateContextAttribs != NULL)
+      {
+      this->Internal->OffScreenContextId = OSMesaCreateContextAttribs(attribs, NULL);
+      }
+#endif
+    // if we still have no context fall back to the generic signature
     if (!this->Internal->OffScreenContextId)
       {
       this->Internal->OffScreenContextId = OSMesaCreateContext(GL_RGBA, NULL);
-- 
GitLab


From 561c9b6403f4562d91e4fe36e55713747fa22d39 Mon Sep 17 00:00:00 2001
From: Utkarsh Ayachit <utkarsh.ayachit@kitware.com>
Date: Wed, 6 Jul 2016 15:26:57 -0400
Subject: [PATCH 2/2] Add support for on and off screen Mesa in same build.

On and Off scrreen Mesa can now be enabled in the same version of VTK.
Tested with Mesa 12.0.0-rc2, but has been reported to work with 11.2 as
well.
---
 CMake/vtkOpenGL.cmake | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/CMake/vtkOpenGL.cmake b/CMake/vtkOpenGL.cmake
index a1d69c2927f..f4177f4ecaf 100644
--- a/CMake/vtkOpenGL.cmake
+++ b/CMake/vtkOpenGL.cmake
@@ -19,9 +19,11 @@ option(VTK_USE_X "Use X for VTK render windows" ${VTK_USE_X_DEFAULT})
 # OSMesa logic for offscreen mesa rendering.
 option(VTK_OPENGL_HAS_OSMESA
   "The OpenGL library being used supports off screen Mesa calls" OFF)
+
 # EGL offscreen rendering
 option(VTK_USE_OFFSCREEN_EGL
   "Use EGL for OpenGL client API for offscreen rendering." OFF)
+
 set(VTK_EGL_DEVICE_INDEX 0 CACHE STRING
   "Index of the EGL device (graphics card) to use.")
 
@@ -33,21 +35,26 @@ if (VTK_USE_OFFSCREEN_EGL AND ANDROID)
 endif()
 
 option(VTK_USE_OFFSCREEN "Use off screen calls by default" OFF)
+
 unset(VTK_CAN_DO_OFFSCREEN)
+unset(VTK_CAN_DO_ONSCREEN)
+
 if(VTK_OPENGL_HAS_OSMESA OR WIN32 OR VTK_USE_OFFSCREEN_EGL)
   set(VTK_CAN_DO_OFFSCREEN 1)
 endif()
+
 if(VTK_USE_X OR VTK_USE_COCOA OR WIN32 OR ANDROID OR APPLE_IOS)
-  set(VTK_USE_OSMESA FALSE)
+  set(VTK_USE_OSMESA ${VTK_OPENGL_HAS_OSMESA})
   if (VTK_USE_OFFSCREEN_EGL)
     message(FATAL_ERROR "VTK_USE_OFFSCREEN_EGL set together with one of ("
       "VTK_USE_X, VTK_USE_COCOA, WIN32, ANDROID OR APPLE_IOS). "
       "You cannot use both offscreen and one of the listed windowing systems.")
   endif()
+  set(VTK_CAN_DO_ONSCREEN 1)
 elseif(VTK_USE_OFFSCREEN_EGL)
   set(VTK_USE_OSMESA FALSE)
 else()
-  set(VTK_USE_OSMESA TRUE)
+  set(VTK_USE_OSMESA ${VTK_OPENGL_HAS_OSMESA})
 endif()
 
 mark_as_advanced(VTK_USE_X VTK_OPENGL_HAS_OSMESA VTK_USE_OFFSCREEN_EGL
@@ -56,10 +63,17 @@ mark_as_advanced(VTK_USE_X VTK_OPENGL_HAS_OSMESA VTK_USE_OFFSCREEN_EGL
 if(VTK_USE_OSMESA)
   find_package(OSMesa REQUIRED)
   include_directories(SYSTEM ${OSMESA_INCLUDE_DIR})
-elseif(VTK_USE_OFFSCREEN_EGL)
-    find_package(EGL REQUIRED)
-    include_directories(SYSTEM ${EGL_INCLUDE_DIR})
-else()
+endif()
+
+if(VTK_USE_OFFSCREEN_EGL)
+  find_package(EGL REQUIRED)
+  include_directories(SYSTEM ${EGL_INCLUDE_DIR})
+endif()
+
+if(VTK_CAN_DO_ONSCREEN)
+  # OpenGL libraries are explicity needed if windowing system-based API is being
+  # used. Otherwise, if only doing OFFSCREEN, the GL API is provided by the
+  # offscreen library be it EGL or OSMESA.
   find_package(OpenGL REQUIRED)
   include_directories(SYSTEM ${OPENGL_INCLUDE_DIR})
   if(APPLE)
@@ -83,9 +97,11 @@ endif()
 function(vtk_opengl_link target)
   if(VTK_USE_OSMESA)
     vtk_module_link_libraries(${target} LINK_PRIVATE ${OSMESA_LIBRARY})
-  elseif(VTK_USE_OFFSCREEN_EGL)
+  endif()
+  if(VTK_USE_OFFSCREEN_EGL)
     vtk_module_link_libraries(${target} LINK_PRIVATE ${EGL_LIBRARIES})
-  else()
+  endif()
+  if(VTK_CAN_DO_ONSCREEN)
     vtk_module_link_libraries(${target} LINK_PRIVATE ${OPENGL_LIBRARIES})
   endif()
 endfunction()
-- 
GitLab