# Visualization Library

A lightweight C++ OpenGL middleware for 2D/3D graphics

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# D:/VL/BuildSystem/VL_DISTRO/Visualization_Library_SDK/src/vlGraphics/PixelLODEvaluator.cpp

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    00001 /**************************************************************************************/
    00002 /*                                                                                    */
    00003 /*  Visualization Library                                                             */
    00004 /*  http://www.visualizationlibrary.org                                               */
    00005 /*                                                                                    */
    00006 /*  Copyright (c) 2005-2010, Michele Bosi                                             */
    00007 /*  All rights reserved.                                                              */
    00008 /*                                                                                    */
    00009 /*  Redistribution and use in source and binary forms, with or without modification,  */
    00010 /*  are permitted provided that the following conditions are met:                     */
    00011 /*                                                                                    */
    00012 /*  - Redistributions of source code must retain the above copyright notice, this     */
    00013 /*  list of conditions and the following disclaimer.                                  */
    00014 /*                                                                                    */
    00015 /*  - Redistributions in binary form must reproduce the above copyright notice, this  */
    00016 /*  list of conditions and the following disclaimer in the documentation and/or       */
    00017 /*  other materials provided with the distribution.                                   */
    00018 /*                                                                                    */
    00019 /*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND   */
    00020 /*  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED     */
    00021 /*  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE            */
    00022 /*  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR  */
    00023 /*  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES    */
    00024 /*  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;      */
    00025 /*  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON    */
    00026 /*  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT           */
    00027 /*  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS     */
    00028 /*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.                      */
    00029 /*                                                                                    */
    00030 /**************************************************************************************/
    00031
    00032 #include <vlGraphics/PixelLODEvaluator.hpp>
    00033 #include <vlGraphics/Camera.hpp>
    00034
    00035 using namespace vl;
    00036
    00037 //-----------------------------------------------------------------------------
    00038 int PixelLODEvaluator::evaluate(Actor* actor, Camera* camera)
    00039 {
    00040   if (mPixelRangeSet.empty())
    00041     return 0;
    00042
    00043   AABB aabb = actor->transform() ? actor->lod(0)->boundingBox().transformed( actor->transform()->worldMatrix() ) : actor->lod(0)->boundingBox();
    00044
    00045   vec3 corner[] =
    00046   {
    00047     vec3(aabb.minCorner().x(), aabb.minCorner().y(), aabb.minCorner().z()),
    00048     vec3(aabb.minCorner().x(), aabb.maxCorner().y(), aabb.minCorner().z()),
    00049     vec3(aabb.maxCorner().x(), aabb.maxCorner().y(), aabb.minCorner().z()),
    00050     vec3(aabb.maxCorner().x(), aabb.minCorner().y(), aabb.minCorner().z()),
    00051     vec3(aabb.minCorner().x(), aabb.minCorner().y(), aabb.maxCorner().z()),
    00052     vec3(aabb.minCorner().x(), aabb.maxCorner().y(), aabb.maxCorner().z()),
    00053     vec3(aabb.maxCorner().x(), aabb.maxCorner().y(), aabb.maxCorner().z()),
    00054     vec3(aabb.maxCorner().x(), aabb.minCorner().y(), aabb.maxCorner().z())
    00055   };
    00056
    00057   mat4 proj_matrix = camera->projectionMatrix() * camera->viewMatrix();
    00058
    00059   aabb.setNull();
    00060
    00061   // project the 8 corners in the viewport
    00062   for(int i=0; i<8; ++i)
    00063   {
    00064     vec4 out = proj_matrix * vec4(corner[i],1);
    00065
    00066     if (out.w() == 0.0f)
    00067       continue;
    00068
    00069     out.x() /= out.w();
    00070     out.y() /= out.w();
    00071     out.z() /= out.w();
    00072
    00073     // map to range 0-1
    00074     out.x() = out.x() * 0.5f + 0.5f;
    00075     out.y() = out.y() * 0.5f + 0.5f;
    00076     out.z() = out.z() * 0.5f + 0.5f;
    00077
    00078     // map to viewport
    00079     out.x() = out.x() * camera->viewport()->width()  + camera->viewport()->x();
    00080     out.y() = out.y() * camera->viewport()->height() + camera->viewport()->y();
    00081
    00082     aabb.addPoint(out.xyz());
    00083   }
    00084
    00085   double pixels = aabb.width() * aabb.height();
    00086
    00087   // we assume the distances are sorted in increasing order
    00088   int i=0;
    00089   for(; i<(int)mPixelRangeSet.size(); ++i)
    00090   {
    00091     if (pixels>mPixelRangeSet[mPixelRangeSet.size() - 1 - i])
    00092       return i;
    00093   }
    00094
    00095   return i; // == mPixelRangeSet.size()
    00096 }
    00097 //-----------------------------------------------------------------------------

Visualization Library v2011.09.1162 Reference Documentation
Copyright 2005-2011 Michele Bosi. All rights reserved.
Updated on Thu Jan 26 2012 00:43:40.
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