1 files changed, 72 insertions, 0 deletions
diff --git a/libdimensionxx/gl.cpp b/libdimensionxx/gl.cpp
new file mode 100644
index 0000000..5c0a7bb
--- /dev/null
+++ b/libdimensionxx/gl.cpp
@@ -0,0 +1,72 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library 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  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimensionxx.hpp"
+#include <cstdio>
+
+namespace Dimension
+{
+  GL_Drawer::GL_Drawer(Canvas& canvas)
+    : m_canvas(&canvas), m_drawn(false)
+  {
+    // Optimize the canvas for GL drawing
+    dmnsn_gl_optimize_canvas(m_canvas->dmnsn());
+  }
+
+  // Draw the canvas if it hasn't been drawn yet
+  GL_Drawer::~GL_Drawer()
+  {
+    if (!m_drawn) {
+      try {
+        draw();
+      } catch (...) {
+        dmnsn_error(SEVERITY_MEDIUM,
+                    "Drawing canvas to GL failed in GL_Drawer destructor.");
+      }
+    }
+  }
+
+  // Draw the canvas to the current openGL buffer
+  void GL_Drawer::draw()
+  {
+    // Draw to the GL buffer
+    if (dmnsn_gl_write_canvas(m_canvas->dmnsn()) != 0) {
+      // The drawing operation failed
+      throw Dimension_Error("Drawing canvas to GL failed.");
+    }
+
+    m_drawn = true; // Don't draw again in destructor
+  }
+
+  // Read a canvas from a GL buffer
+  Canvas
+  GL_Reader::read(unsigned int x0, unsigned int y0,
+                  unsigned int width, unsigned int height)
+  {
+    // Read the canvas from the GL buffer
+    dmnsn_canvas* canvas = dmnsn_gl_read_canvas(x0, y0, width, height);
+    if (!canvas) {
+      // The read operation failed
+      throw Dimension_Error("Reading canvas from GL failed.");
+    }
+
+    return Canvas(canvas);
+  }
+}