Initial revision

git-svn-id: file:///fltk/svn/fltk/trunk@2 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 98 insertions, 0 deletions

diff --git a/src/gl_start.cxx b/src/gl_start.cxx
new file mode 100644
index 000000000..255a78127
--- /dev/null
+++ b/src/gl_start.cxx
@@ -0,0 +1,98 @@
+// Code to switch current fltk drawing context in/out of GL "mode":
+
+// You MUST use gl_visual() to select the default visual before doing
+// show() of any windows.  Mesa will crash if you try to use a visual
+// not returned by glxChooseVisual.
+
+// This does not work with Fl_Double_Window's!  It will try to draw
+// into the front buffer.  Depending on the system this will either
+// crash or do nothing (when pixmaps are being used as back buffer
+// and GL is being done by hardware), work correctly (when GL is done
+// with software, such as Mesa), or draw into the front buffer and
+// be erased when the buffers are swapped (when double buffer hardware
+// is being used)
+
+#include <config.h>
+#if HAVE_GL
+
+#include <FL/Fl.H>
+#include <FL/Fl_Window.H>
+#include <FL/x.H>
+#include <FL/fl_draw.H>
+
+#include "Fl_Gl_Choice.H"
+
+extern GLXContext fl_first_context; // in Fl_Gl_Choice.C
+extern int fl_clip_state_number; // in fl_rect.C
+
+static GLXContext context;
+static int clip_state_number;
+static int pw, ph;
+
+#ifdef WIN32
+static int default_mode;
+#endif
+
+Region XRectangleRegion(int x, int y, int w, int h); // in fl_rect.C
+
+void gl_start() {
+#ifdef WIN32
+  HDC hdc = fl_private_dc(Fl_Window::current(), default_mode,0);
+  if (!context) {
+    context = wglCreateContext(hdc);
+    if (!fl_first_context) fl_first_context = context;
+    else wglShareLists(fl_first_context, context);
+  }
+  wglMakeCurrent(hdc, context);
+#else
+  if (!context) {
+    context = glXCreateContext(fl_display, fl_visual, fl_first_context, 1);
+    if (!context) Fl::fatal("OpenGL does not support this visual");
+    if (!fl_first_context) fl_first_context = context;
+  }
+  glXMakeCurrent(fl_display, fl_window, context);
+  glXWaitX();
+#endif
+  if (pw != Fl_Window::current()->w() || ph != Fl_Window::current()->h()) {
+    pw = Fl_Window::current()->w();
+    ph = Fl_Window::current()->h();
+    glLoadIdentity();
+    glViewport(0, 0, pw, ph);
+    glOrtho(0, pw, 0, ph, -1, 1);
+    glDrawBuffer(GL_FRONT);
+  }
+  if (clip_state_number != fl_clip_state_number) {
+    clip_state_number = fl_clip_state_number;
+    int x, y, w, h;
+    if (fl_clip_box(0, 0, Fl_Window::current()->w(), Fl_Window::current()->h(),
+		    x, y, w, h)) {
+      fl_clip_region(XRectangleRegion(x,y,w,h));
+      glScissor(x, Fl_Window::current()->h()-(y+h), w, h);
+      glEnable(GL_SCISSOR_TEST);
+    } else {
+      glDisable(GL_SCISSOR_TEST);
+    }
+  }
+}
+
+void gl_finish() {
+#ifdef WIN32
+  glFlush();
+#else
+  glXWaitGL();
+#endif
+}
+
+int Fl::gl_visual(int mode, int *alist) {
+#ifdef WIN32
+  default_mode = mode;
+#else
+  Fl_Gl_Choice *c = Fl_Gl_Choice::find(mode,alist);
+  if (!c) return 0;
+  fl_visual = c->vis;
+  fl_colormap = c->colormap;
+#endif
+  return 1;
+}
+
+#endif