bring in support for multiresolution volume rendering

include/openspace/rendering/transferfunction.h

@@ -0,0 +1,70 @@
+/*****************************************************************************************
+ *                                                                                       *
+ * OpenSpace                                                                             *
+ *                                                                                       *
+ * Copyright (c) 2014-2015                                                               *
+ *                                                                                       *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
+ * software and associated documentation files (the "Software"), to deal in the Software *
+ * without restriction, including without limitation the rights to use, copy, modify,    *
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
+ * permit persons to whom the Software is furnished to do so, subject to the following   *
+ * conditions:                                                                           *
+ *                                                                                       *
+ * The above copyright notice and this permission notice shall be included in all copies *
+ * or substantial portions of the Software.                                              *
+ *                                                                                       *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
+ * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
+ * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
+ * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
+ ****************************************************************************************/
+
+#ifndef __TRANSFERFUNCTION_H__
+#define __TRANSFERFUNCTION_H__
+
+#include <string>
+#include <glm/glm.hpp>
+#include <functional>
+#include <ghoul/opengl/texture.h>
+#include <ghoul/filesystem/file.h>
+#include <memory>
+
+namespace openspace {
+
+    class TransferFunction {
+    public:
+        typedef std::function<void (const TransferFunction&)> TfChangedCallback;
+
+        TransferFunction(const std::string& filepath, TfChangedCallback tfChangedCallback = TfChangedCallback());
+        void setPath(const std::string& filepath);
+        ghoul::opengl::Texture& getTexture();
+        void update();
+        glm::vec4 sample(size_t t);
+        size_t width();
+        void setCallback(TfChangedCallback callback);
+    private:
+        void setTextureFromTxt();
+        void setTextureFromImage();
+        void uploadTexture();
+
+        std::string _filepath;
+        std::unique_ptr<ghoul::filesystem::File> _file = nullptr;
+        std::unique_ptr<ghoul::opengl::Texture> _texture = nullptr;
+        bool _needsUpdate = false;
+        TfChangedCallback _tfChangedCallback;
+    };
+
+    struct MappingKey {
+        float position{0.0f};
+        glm::vec4 color{0.0f,0.0f,0.0f,0.0f};
+        MappingKey(float p, const glm::vec4& c): position(p), color(c) {};
+        MappingKey(float p): position(p), color(glm::vec4(0.0f)) {};
+        bool operator<(const MappingKey& rhs) {return position < rhs.position;};
+    };
+} // namespace openspace
+
+#endif
+