Linux offscreen OpenGL using glxpixmaps. also fix FBO ARB/EXT issues

6 files changed, 297 insertions, 85 deletions

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index eb3e911..9e6640e 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -57,21 +57,6 @@ if (NOT OPENCSG_INCLUDE_DIR)
 endif()
 include_directories(${OPENCSG_INCLUDE_DIR})
 
-# SDL (for OpenCSG on Linux & other platforms)
-if (NOT $ENV{MACOSX_DEPLOY_DIR} STREQUAL "")
-  message(STATU "SDL not needed for Mac OSX")
-else()
-  find_package(SDL REQUIRED)
-  if (NOT SDL_FOUND)
-    message(FATAL_ERROR "SDL not found.")
-  else()
-    message(STATUS "SDL library found in " ${SDL_LIBRARY})
-    message(STATUS "SDL header found in " ${SDL_INCLUDE_DIR})
-    set(OPENGL_LIBRARY ${OPENGL_LIBRARY} ${SDL_LIBRARY})
-  endif()
-endif()
-include_directories(${SDL_INCLUDE_DIR})
-
 # GLEW
 
 if (NOT $ENV{MACOSX_DEPLOY_DIR} STREQUAL "")
diff --git a/tests/OffscreenContext.cc b/tests/OffscreenContext.cc
index fa1afde..775491e 100644
--- a/tests/OffscreenContext.cc
+++ b/tests/OffscreenContext.cc
@@ -1,85 +1,182 @@
+/*
+
+Create an OpenGL context without creating an OpenGL Window. for Linux.
+
+based on
+
+ http://www.opengl.org/sdk/docs/man/xhtml/glXIntro.xml
+ http://www.mesa3d.org/brianp/sig97/offscrn.htm
+ http://glprogramming.com/blue/ch07.html
+ OffscreenContext.mm (Mac OSX version)
+
+*/
+
 #include "OffscreenContext.h"
 #include "printutils.h"
 #include "imageutils.h"
+#include "fbo.h"
 
-// see http://www.gamedev.net/topic/552607-conflict-between-glew-and-sdl/
-#define NO_SDL_GLEXT
-#include <GL/glew.h>
-
-#define GL_GLEXT_PROTOTYPES
 #include <GL/gl.h>
-#include <GL/glext.h>
+#include <GL/glx.h>
 
-//#include <GL/gl.h>
-//#include <GL/glu.h>      // for gluCheckExtension
-#include <SDL.h>
+#define REPORTGLERROR(task) { GLenum tGLErr = glGetError(); if (tGLErr != GL_NO_ERROR) { std::cout << "OpenGL error " << tGLErr << " while " << task << "\n"; } }
 
 struct OffscreenContext
 {
+  GLXContext openGLContext;
+  Display *xDisplay;
+  GLXPixmap glx_pixmap;
+  Pixmap x11_pixmap;
   int width;
   int height;
-  GLuint fbo;
-  GLuint colorbo;
-  GLuint depthbo;
+  fbo_t *fbo;
 };
 
-void write_targa(const char *filename, GLubyte *pixels, int width, int height)
+Bool glx_1_3_pixmap_dummy_context(OffscreenContext *ctx, Bool hybrid)
+{
+	XVisualInfo *vInfo;
+	GLXFBConfig *fbConfigs;
+
+	int numReturned;
+	int result;
+	int dummyAttributes_1_3[] = {
+		GLX_DRAWABLE_TYPE, GLX_PIXMAP_BIT,
+		GLX_RENDER_TYPE,   GLX_RGBA_BIT,
+		None
+	};
+
+	fbConfigs = glXChooseFBConfig( ctx->xDisplay,
+	 	DefaultScreen(ctx->xDisplay),
+		dummyAttributes_1_3, &numReturned );
+	if ( fbConfigs == NULL ) {
+		REPORTGLERROR("glXChooseFBConfig failed") ;
+		return False;
+	}
+
+	vInfo = glXGetVisualFromFBConfig( ctx->xDisplay, fbConfigs[0] );
+	if ( vInfo == NULL ) {
+		REPORTGLERROR("glXGetVisualFromFBConfig failed") ;
+		return False;
+	}
+
+	ctx->x11_pixmap = XCreatePixmap( ctx->xDisplay, DefaultRootWindow(ctx->xDisplay) , 10, 10, 8 );
+
+	if (hybrid) {
+		// GLX 1.2 - prevent Mesa warning
+		ctx->glx_pixmap = glXCreateGLXPixmap( ctx->xDisplay, vInfo, ctx->x11_pixmap );
+	} else {
+		// GLX 1.3
+		ctx->glx_pixmap = glXCreatePixmap( ctx->xDisplay, fbConfigs[0], ctx->x11_pixmap, NULL ); // GLX 1.3
+	}
+
+	ctx->openGLContext = glXCreateNewContext( ctx->xDisplay, fbConfigs[0], GLX_RGBA_TYPE, NULL, True );
+	if ( ctx->openGLContext == NULL ) {
+		REPORTGLERROR("glXCreateNewContext failed" );
+		return False;
+	}
+
+	result = glXMakeContextCurrent( ctx->xDisplay, ctx->glx_pixmap, ctx->glx_pixmap, ctx->openGLContext );
+	if ( result == False ) {
+		REPORTGLERROR("glXMakeContextCurrent failed" );
+		return False;
+	}
+
+	return True;
+}
+
+Bool make_glx_dummy_context(OffscreenContext *ctx)
 {
-	FILE *f = fopen( filename, "w" );
-	int y;
-	if (f) {
-		GLubyte header[] = {
-			00,00,02, 00,00,00, 00,00,00, 00,00,00,
-			0xff & width, 0xff & width >> 8,
-			0xff & height, 0xff & height >> 8,
-			32, 0x20 }; // next-to-last = bit depth
-		fwrite( header, sizeof(header), 1, f);
-		for (y=height-1; y>=0; y--)
-			fwrite( pixels + y*width*4, 4, width, f);
-		fclose(f);
+	/*
+	Before opening a framebuffer, an OpenGL context must be created.
+	For GLX, you can do this by creating a 'Pixmap' drawable then
+	creating the Context off of that. The Pixmap is then never used.
+	*/
+	int major;
+	int minor;
+
+	ctx->xDisplay = XOpenDisplay( NULL );
+	if ( ctx->xDisplay == NULL ) {
+		fprintf(stderr, "Unable to open a connection to the X server\n" );
+		return False;
+	}
+
+	/*
+	On some systems, the GLX library will report that it is version
+	1.2, but some 1.3 functions will be implemented, and, furthermore,
+	some 1.2 functions won't work right, while the 1.3 functions will,
+	but glXCreatePixmp will still generate a MESA GLX 1.3 runtime warning.
+
+	To workaround this, detect the situation and use 'hybrid' mix of
+	1.2 and 1.3 as needed.
+	*/
+	glXQueryVersion(ctx->xDisplay, &major, &minor);
+
+	if (major==1 && minor<=2) {
+		if (glXCreatePixmap!=NULL) { // 1.3 function exists, even though its 1.2
+			return glx_1_3_pixmap_dummy_context(ctx,True);
+		} else {
+			fprintf(stderr,"OpenGL error: GLX version 1.3 functions missing. Your GLX: %i.%i\n",major,minor);
+			return False;
+		}
+	} else if (major>=1 && minor>=3) {
+		return glx_1_3_pixmap_dummy_context(ctx,False);
 	}
 }
 
+void glewCheck() {
+#ifdef DEBUG
+  cout << "GLEW version " << glewGetString(GLEW_VERSION) << "\n";
+  cout << (const char *)glGetString(GL_RENDERER) << "(" << (const char *)glGetString(GL_VENDOR) << ")\n"
+       << "OpenGL version " << (const char *)glGetString(GL_VERSION) << "\n";
+  cout  << "Extensions: " << (const char *)glGetString(GL_EXTENSIONS) << "\n";
+
+  if (GLEW_ARB_framebuffer_object) {
+    cout << "ARB_FBO supported\n";
+  }
+  if (GLEW_EXT_framebuffer_object) {
+    cout << "EXT_FBO supported\n";
+  }
+  if (GLEW_EXT_packed_depth_stencil) {
+    cout << "EXT_packed_depth_stencil\n";
+  }
+#endif
+}
+
 OffscreenContext *create_offscreen_context(int w, int h)
 {
   OffscreenContext *ctx = new OffscreenContext;
   ctx->width = w;
   ctx->height = h;
+  ctx->openGLContext = NULL;
+  ctx->xDisplay = NULL;
+  ctx->glx_pixmap = NULL;
+  ctx->x11_pixmap = NULL;
+  ctx->fbo = NULL;
+
+  // fill ctx->xDisplay, ctx->openGLContext, x11_pixmap, glx_pixmap
+  if (!make_glx_dummy_context(ctx)) {
+    return NULL;
+  }
 
-  // dummy window 
-  SDL_Init(SDL_INIT_VIDEO);
-  SDL_SetVideoMode(ctx->width,ctx->height,32,SDL_OPENGL);
-
-  // must come after openGL context init (done by dummy window)
-  // but must also come before various EXT calls
-  //glewInit();
+  glewInit(); //must come after Context creation and before FBO calls.
+  glewCheck();
 
-/*
-	glClearColor(1, 1, 1, 1);
-	glClear(GL_COLOR_BUFFER_BIT);
-	glBegin(GL_TRIANGLES);
-	glColor3f( 1, 0, 0);
-	glVertex3f( 0, 0, 0);
-	glVertex3f( 1, 0, 0);
-	glVertex3f( 0, 1, 0);
-	glEnd();
-        SDL_GL_SwapBuffers();
-//  sleep(2);
-*/
-
-  int samplesPerPixel = 4; // R, G, B and A
+  ctx->fbo = fbo_new();
+  if (!fbo_init(ctx->fbo, w, h)) {
+    return NULL;
+  }
 
-/*  char * filename = "blah.tga";
-  GLubyte pixels[ ctx->width * ctx->height * samplesPerPixel ];
-  glReadPixels(0, 0, ctx->width, ctx->height, GL_BGRA, GL_UNSIGNED_BYTE, pixels);
-  printf("writing %s\n",filename);
-  write_targa(filename,pixels,ctx->width, ctx->height);*/
   return ctx;
 }
 
 bool teardown_offscreen_context(OffscreenContext *ctx)
 {
-  return true;
+	fbo_unbind(ctx->fbo);
+	fbo_delete(ctx->fbo);
+	glXDestroyPixmap(ctx->xDisplay, ctx->glx_pixmap );
+	XFreePixmap(ctx->xDisplay, ctx->x11_pixmap );
+	glXDestroyContext( ctx->xDisplay, ctx->openGLContext );
+	return true;
 }
 
 /*!
@@ -87,8 +184,6 @@ bool teardown_offscreen_context(OffscreenContext *ctx)
 */
 bool save_framebuffer(OffscreenContext *ctx, const char *filename)
 {
-  SDL_GL_SwapBuffers(); // show image
-
   int samplesPerPixel = 4; // R, G, B and A
   GLubyte pixels[ctx->width * ctx->height * samplesPerPixel];
   glReadPixels(0, 0, ctx->width, ctx->height, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
@@ -111,4 +206,5 @@ bool save_framebuffer(OffscreenContext *ctx, const char *filename)
 
 void bind_offscreen_context(OffscreenContext *ctx)
 {
+	fbo_bind(ctx->fbo);
 }
diff --git a/tests/OffscreenView.cc b/tests/OffscreenView.cc
index 8a4b57d..d188d0d 100644
--- a/tests/OffscreenView.cc
+++ b/tests/OffscreenView.cc
@@ -14,7 +14,8 @@ OffscreenView::OffscreenView(size_t width, size_t height)
 		object_rot(35, 0, 25), camera_eye(0, 0, 0), camera_center(0, 0, 0)
 {
 	for (int i = 0; i < 10; i++) this->shaderinfo[i] = 0;
-  this->ctx = create_offscreen_context(width, height);
+	this->ctx = create_offscreen_context(width, height);
+	if ( this->ctx == NULL ) throw -1;
 	initializeGL();
 	resizeGL(width, height);
 }
@@ -185,7 +186,7 @@ void OffscreenView::paintGL()
 	glMatrixMode(GL_MODELVIEW);
 	glLoadIdentity();
 
-	glClearColor(1.0, 1.0, 0.92, 0.0);
+	glClearColor(1.0, 1.0, 0.92, 1.0);
 
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
diff --git a/tests/cgalpngtest.cc b/tests/cgalpngtest.cc
index 638c088..447df45 100644
--- a/tests/cgalpngtest.cc
+++ b/tests/cgalpngtest.cc
@@ -179,7 +179,12 @@ int main(int argc, char **argv)
 	QDir::setCurrent(original_path.absolutePath());
 
 // match with csgtest ends
-	csgInfo.glview = new OffscreenView(512,512);
+       try {
+                csgInfo.glview = new OffscreenView(512,512);
+        } catch (int error) {
+                fprintf(stderr,"Can't create OpenGL OffscreenView. exiting.\n");
+                exit(1);
+        }
 
   GLenum err = glewInit();
   if (GLEW_OK != err) {
diff --git a/tests/csgtestcore.cc b/tests/csgtestcore.cc
index 6ef05f3..2e28bf6 100644
--- a/tests/csgtestcore.cc
+++ b/tests/csgtestcore.cc
@@ -218,7 +218,12 @@ int csgtestcore(int argc, char *argv[], test_type_e test_type)
 	
 	QDir::setCurrent(original_path.absolutePath());
 
-	csgInfo.glview = new OffscreenView(512,512);
+        try {
+                csgInfo.glview = new OffscreenView(512,512);
+        } catch (int error) {
+                fprintf(stderr,"Can't create OpenGL OffscreenView. exiting.\n");
+                exit(1);
+        }
 	BoundingBox bbox = csgInfo.root_chain->getBoundingBox();
 
 	Vector3d center = (bbox.min() + bbox.max()) / 2;
diff --git a/tests/fbo.cc b/tests/fbo.cc
index 403a32e..b7bf1c0 100644
--- a/tests/fbo.cc
+++ b/tests/fbo.cc
@@ -15,13 +15,94 @@ fbo_t *fbo_new()
 
 #define REPORTGLERROR(task) { GLenum tGLErr = glGetError(); if (tGLErr != GL_NO_ERROR) { std::cout << "OpenGL error " << tGLErr << " while " << task << "\n"; } }
 
-bool fbo_init(fbo_t *fbo, size_t width, size_t height)
+bool use_ext()
+{
+  // do we need to use the EXT or ARB version?
+  if (!glewIsSupported("GL_ARB_framebuffer_object") &&
+        glewIsSupported("GL_EXT_framebuffer_object")) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+bool check_fbo_status()
 {
-  if (!glewIsSupported("GL_ARB_framebuffer_object")) {
-    fprintf(stderr, "Framebuffer extension not found\n");
+	/* This code is based on user V-man code from
+	http://www.opengl.org/wiki/GL_EXT_framebuffer_multisample
+	See also: http://www.songho.ca/opengl/gl_fbo.html */
+	GLenum status;
+	bool result = false;
+	if (use_ext())
+		status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+	else
+		status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+
+	if (glGetError() != GL_NO_ERROR)
+		fprintf(stderr, "OpenGL Error %i\n",glGetError());
+
+	if (status == GL_FRAMEBUFFER_COMPLETE)
+		result = true;
+	else if (status == GL_FRAMEBUFFER_UNSUPPORTED)
+		fprintf(stderr, "GL_FRAMEBUFFER_UNSUPPORTED\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT\n");
+	else if (status == GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT)
+		fprintf(stderr, "GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT\n");
+	else
+		fprintf(stderr, "Unknown Code: glCheckFramebufferStatusEXT returned %i\n",status);
+	return result;
+}
+
+bool fbo_ext_init(fbo_t *fbo, size_t width, size_t height)
+{
+  // Generate and bind FBO
+  glGenFramebuffersEXT(1, &fbo->fbo_id);
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo->fbo_id);
+  REPORTGLERROR("binding framebuffer");
+
+  // Generate depth and render buffers
+  glGenRenderbuffersEXT(1, &fbo->depthbuf_id);
+  glGenRenderbuffersEXT(1, &fbo->renderbuf_id);
+
+  // Create buffers with correct size
+  if (!fbo_resize(fbo, width, height)) return false;
+
+  // Attach render and depth buffers
+  glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, 
+                               GL_RENDERBUFFER_EXT, fbo->renderbuf_id);
+  REPORTGLERROR("specifying color render buffer");
+
+
+  if (!check_fbo_status()) {
+    fprintf(stderr, "Problem with OpenGL framebuffer after specifying color render buffer.\n");
+    return false;
+  }
+
+  glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, 
+                               GL_RENDERBUFFER_EXT, fbo->depthbuf_id);
+  REPORTGLERROR("specifying depth render buffer");
+
+  if (!check_fbo_status()) {
+    fprintf(stderr, "Problem with OpenGL framebuffer after specifying depth render buffer.\n");
     return false;
   }
 
+  return true;
+}
+
+bool fbo_arb_init(fbo_t *fbo, size_t width, size_t height)
+{
   // Generate and bind FBO
   glGenFramebuffers(1, &fbo->fbo_id);
   glBindFramebuffer(GL_FRAMEBUFFER, fbo->fbo_id);
@@ -56,15 +137,48 @@ bool fbo_init(fbo_t *fbo, size_t width, size_t height)
   return true;
 }
 
-bool fbo_resize(fbo_t *fbo, size_t width, size_t height)
+
+bool fbo_init(fbo_t *fbo, size_t width, size_t height)
 {
-  glBindRenderbuffer(GL_RENDERBUFFER, fbo->depthbuf_id);
-  glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
-  REPORTGLERROR("creating depth render buffer");
+  /*
+  Some OpenGL drivers include the framebuffer functions but not with
+  core or ARB names, only with the EXT name. This has been worked-around
+  by deciding at runtime, using GLEW, which version needs to be used. See also:
+  
+  http://www.opengl.org/wiki/Framebuffer_Object
+  http://stackoverflow.com/questions/6912988/glgenframebuffers-or-glgenframebuffersex
+  http://www.devmaster.net/forums/showthread.php?t=10967
+  */
+
+  bool result = false;
+  if (glewIsSupported("GL_ARB_framebuffer_object"))
+    result = fbo_arb_init(fbo, width, height);
+  else if (use_ext())
+    result = fbo_ext_init(fbo, width, height);
+  else
+    fprintf(stderr, "Framebuffer Object extension not found by GLEW\n");
+  return result;
+}
 
-  glBindRenderbuffer(GL_RENDERBUFFER, fbo->renderbuf_id);
-  glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, width, height);
-  REPORTGLERROR("creating color render buffer");
+bool fbo_resize(fbo_t *fbo, size_t width, size_t height)
+{
+  if (use_ext()) {
+    glBindRenderbufferEXT(GL_RENDERBUFFER, fbo->depthbuf_id);
+    glRenderbufferStorageEXT(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
+    REPORTGLERROR("creating depth render buffer");
+
+    glBindRenderbufferEXT(GL_RENDERBUFFER, fbo->renderbuf_id);
+    glRenderbufferStorageEXT(GL_RENDERBUFFER, GL_RGBA8, width, height);
+    REPORTGLERROR("creating color render buffer");
+  } else {
+    glBindRenderbuffer(GL_RENDERBUFFER, fbo->depthbuf_id);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
+    REPORTGLERROR("creating depth render buffer");
+
+    glBindRenderbuffer(GL_RENDERBUFFER, fbo->renderbuf_id);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, width, height);
+    REPORTGLERROR("creating color render buffer");
+  }
 
   return true;
 }
@@ -77,11 +191,17 @@ void fbo_delete(fbo_t *fbo)
 GLuint fbo_bind(fbo_t *fbo)
 {
   glGetIntegerv(GL_FRAMEBUFFER_BINDING, (GLint *)&fbo->old_fbo_id);
-  glBindFramebuffer(GL_FRAMEBUFFER, fbo->fbo_id);
+  if (use_ext())
+    glBindFramebufferEXT(GL_FRAMEBUFFER, fbo->fbo_id);
+  else
+    glBindFramebuffer(GL_FRAMEBUFFER, fbo->fbo_id);
   return fbo->old_fbo_id;
 }
 
 void fbo_unbind(fbo_t *fbo)
 {
-  glBindFramebuffer(GL_FRAMEBUFFER, fbo->old_fbo_id);
+  if (use_ext())
+    glBindFramebufferEXT(GL_FRAMEBUFFER, fbo->old_fbo_id);
+  else
+    glBindFramebuffer(GL_FRAMEBUFFER, fbo->old_fbo_id);
 }