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OpenSpace/modules/globebrowsing/rendering/frustrumculler.cpp

110 lines
4.9 KiB
C++

/*****************************************************************************************
* *
* OpenSpace *
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* Copyright (c) 2014-2016 *
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* 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 *
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* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software. *
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* 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 *
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#include <modules/globebrowsing/rendering/frustrumculler.h>
namespace {
const std::string _loggerCat = "FrustrumCuller";
}
namespace openspace {
//////////////////////////////////////////////////////////////////////////////////////
// PATCH RENDERER //
//////////////////////////////////////////////////////////////////////////////////////
FrustrumCuller::FrustrumCuller()
{
}
FrustrumCuller::~FrustrumCuller() {
}
bool FrustrumCuller::isVisible(const RenderData& data, const vec3& point, const glm::vec2& marginScreenSpace) {
mat4 modelTransform = translate(mat4(1), data.position.vec3());
mat4 viewTransform = data.camera.combinedViewMatrix();
mat4 modelViewProjectionTransform = data.camera.projectionMatrix()
* viewTransform * modelTransform;
vec2 pointScreenSpace = transformToScreenSpace(point, modelViewProjectionTransform);
return testPoint(pointScreenSpace, marginScreenSpace);
}
bool FrustrumCuller::isVisible(const RenderData& data, const LatLonPatch& patch, double radius) {
// An axis aligned bounding box based on the patch's minimum boudning sphere is
// used for testnig
// Calculate the MVP matrix
mat4 modelTransform = translate(mat4(1), data.position.vec3());
mat4 viewTransform = data.camera.combinedViewMatrix();
mat4 modelViewProjectionTransform = data.camera.projectionMatrix()
* viewTransform * modelTransform;
// Calculate the patch's center point in screen space
vec4 patchCenterModelSpace = vec4(radius * patch.center().asUnitCartesian(), 1);
vec4 patchCenterProjectionSpace = modelViewProjectionTransform * patchCenterModelSpace;
vec2 pointScreenSpace = (1.0f / patchCenterProjectionSpace.w) * patchCenterProjectionSpace.xy;
// Calculate the screen space margin that represents an axis aligned bounding
// box based on the patch's minimum boudning sphere
double boundingRadius = radius * patch.minimalBoundingRadius();
vec4 marginProjectionSpace = vec4(vec3(boundingRadius), 0) * data.camera.projectionMatrix();
vec2 marginScreenSpace = (1.0f / patchCenterProjectionSpace.w) * marginProjectionSpace.xy;
// Test the bounding box by testing the center point and the corresponding margin
return testPoint(pointScreenSpace, marginScreenSpace);
}
bool FrustrumCuller::testPoint(const glm::vec2& pointScreenSpace,
const glm::vec2& marginScreenSpace) const
{
const vec2& p = pointScreenSpace;
vec2 cullBounds = vec2(1) + marginScreenSpace;
return ((-cullBounds.x < p.x && p.x < cullBounds.x) &&
(-cullBounds.y < p.y && p.y < cullBounds.y));
}
glm::vec2 FrustrumCuller::transformToScreenSpace(const vec3& point,
const mat4x4& modelViewProjection) const
{
vec4 pointProjectionSpace = modelViewProjection * vec4(point, 1.0f);
vec2 pointScreenSpace = (1.0f / pointProjectionSpace.w) * pointProjectionSpace.xy;
return pointScreenSpace;
}
} // namespace openspace