DEM.h

   1 /***********************************************************************
   2 DEM - Class to represent digital elevation models (DEMs) as float-valued
   3 texture objects.
   4 Copyright (c) 2013-2016 Oliver Kreylos
   5
   6 This file is part of the Augmented Reality Sandbox (SARndbox).
   7
   8 The Augmented Reality Sandbox is free software; you can redistribute it
   9 and/or modify it under the terms of the GNU General Public License as
  10 published by the Free Software Foundation; either version 2 of the
  11 License, or (at your option) any later version.
  12
  13 The Augmented Reality Sandbox is distributed in the hope that it will be
  14 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License along
  19 with the Augmented Reality Sandbox; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21 ***********************************************************************/
  22
  23 #ifndef DEM_INCLUDED
  24 #define DEM_INCLUDED
  25
  26 #include <GL/gl.h>
  27 #include <GL/GLObject.h>
  28
  29 #include "Types.h"
  30
  31 class DEM: public GLObject {
  32     /* Embedded classes: */
  33   private:
  34     struct DataItem: public GLObject::DataItem {
  35         /* Elements: */
  36       public:
  37         GLuint textureObjectId; // ID of texture object holding digital elevation model
  38
  39         /* Constructors and destructors: */
  40         DataItem(void);
  41         virtual ~DataItem(void);
  42     };
  43
  44     /* Elements: */
  45   private:
  46     int demSize[2]; // Width and height of the DEM grid
  47     Scalar demBox[4]; // Lower-left and upper-right corner coordinates of the DEM
  48     float* dem; // Array of DEM elevation measurements
  49     OGTransform transform; // Transformation from camera space to DEM space (z up)
  50     Scalar verticalScale; // Vertical scale (exaggeration) factor
  51     Scalar verticalScaleBase; // Base elevation around which vertical scale is applied
  52     PTransform demTransform; // Full transformation matrix from camera space to DEM pixel space
  53     GLfloat demTransformMatrix[16]; // Full transformation matrix from camera space to DEM pixel space to upload to OpenGL
  54
  55     /* Private methods: */
  56     void calcMatrix(void); // Calculates the camera space to DEM pixel space transformation
  57
  58     /* Constructors and destructors: */
  59   public:
  60     DEM(void); // Creates an uninitialized DEM
  61     virtual ~DEM(void);
  62
  63     /* Methods from class GLObject: */
  64     virtual void initContext(GLContextData& contextData) const;
  65
  66     /* New methods: */
  67     void load(const char* demFileName); // Loads the DEM from the given file
  68     const Scalar* getDemBox(void)
  69     const { // Returns the DEM's bounding box as lower-left x, lower-left y, upper-right x, upper-right y
  70         return demBox;
  71     }
  72     float calcAverageElevation(void) const; // Calculates the average elevation of the DEM
  73     void setTransform(const OGTransform& newTransform, Scalar newVerticalScale,
  74                       Scalar newVerticalScaleBase); // Sets the DEM transformation
  75     const PTransform& getDemTransform(void)
  76     const { // Returns the full transformation from camera space to vertically-scaled DEM pixel space
  77         return demTransform;
  78     }
  79     Scalar getVerticalScale(void)
  80     const { // Returns the scaling factor from camera space elevations to DEM elevations
  81         return transform.getScaling() / verticalScale;
  82     }
  83     void bindTexture(GLContextData& contextData)
  84     const; // Binds the DEM texture object to the currently active texture unit
  85     void uploadDemTransform(GLint location)
  86     const; // Uploads the DEM transformation into the GLSL 4x4 matrix at the given uniform location
  87 };
  88
  89 #endif