mirror of
https://gitlab.kitware.com/vtk/vtk-m
synced 2024-10-05 01:49:02 +00:00
4c1514bb3a
The divide by zero happened when mapping a surface to a depth buffer. Some rays terminated at the origin, which is a singularity in the project matrix. This might be indicative of a larger problem. Rays really shouldn't terminate before the near plane.
162 lines
5.8 KiB
C++
162 lines
5.8 KiB
C++
//============================================================================
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// Copyright (c) Kitware, Inc.
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// All rights reserved.
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// See LICENSE.txt for details.
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//
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// This software is distributed WITHOUT ANY WARRANTY; without even
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// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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// PURPOSE. See the above copyright notice for more information.
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//============================================================================
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#include <vtkm/rendering/CanvasRayTracer.h>
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#include <vtkm/cont/TryExecute.h>
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#include <vtkm/rendering/Canvas.h>
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#include <vtkm/rendering/Color.h>
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#include <vtkm/rendering/raytracing/Ray.h>
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#include <vtkm/worklet/DispatcherMapField.h>
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#include <vtkm/worklet/WorkletMapField.h>
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namespace vtkm
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{
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namespace rendering
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{
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namespace internal
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{
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class SurfaceConverter : public vtkm::worklet::WorkletMapField
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{
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vtkm::Matrix<vtkm::Float32, 4, 4> ViewProjMat;
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public:
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VTKM_CONT
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SurfaceConverter(const vtkm::Matrix<vtkm::Float32, 4, 4> viewProjMat)
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: ViewProjMat(viewProjMat)
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{
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}
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using ControlSignature =
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void(FieldIn, WholeArrayInOut, FieldIn, FieldIn, FieldIn, WholeArrayInOut, WholeArrayInOut);
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using ExecutionSignature = void(_1, _2, _3, _4, _5, _6, _7, WorkIndex);
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template <typename Precision,
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typename ColorPortalType,
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typename DepthBufferPortalType,
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typename ColorBufferPortalType>
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VTKM_EXEC void operator()(const vtkm::Id& pixelIndex,
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ColorPortalType& colorBufferIn,
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const Precision& inDepth,
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const vtkm::Vec<Precision, 3>& origin,
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const vtkm::Vec<Precision, 3>& dir,
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DepthBufferPortalType& depthBuffer,
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ColorBufferPortalType& colorBuffer,
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const vtkm::Id& index) const
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{
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vtkm::Vec<Precision, 3> intersection = origin + inDepth * dir;
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vtkm::Vec4f_32 point;
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point[0] = static_cast<vtkm::Float32>(intersection[0]);
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point[1] = static_cast<vtkm::Float32>(intersection[1]);
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point[2] = static_cast<vtkm::Float32>(intersection[2]);
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point[3] = 1.f;
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vtkm::Float32 depth;
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{
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vtkm::Vec4f_32 newpoint;
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newpoint = vtkm::MatrixMultiply(this->ViewProjMat, point);
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if (newpoint[3] > 0)
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{
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depth = 0.5f * (newpoint[2] / newpoint[3]) + 0.5f;
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}
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else
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{
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// This condition can happen when the ray is at the origin (inDepth = 0), which is a
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// singularity in the projection matrix. I'm not sure this is the right think to do since
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// it looks like depth is supposed to be between 0 and 1. It seems wrong that you would
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// ever get a ray in front of the near plane, so the "right" solution may be to fix this
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// elsewhere.
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depth = vtkm::NegativeInfinity32();
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}
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}
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vtkm::Vec4f_32 color;
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color[0] = static_cast<vtkm::Float32>(colorBufferIn.Get(index * 4 + 0));
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color[1] = static_cast<vtkm::Float32>(colorBufferIn.Get(index * 4 + 1));
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color[2] = static_cast<vtkm::Float32>(colorBufferIn.Get(index * 4 + 2));
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color[3] = static_cast<vtkm::Float32>(colorBufferIn.Get(index * 4 + 3));
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// blend the mapped color with existing canvas color
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vtkm::Vec4f_32 inColor = colorBuffer.Get(pixelIndex);
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// if transparency exists, all alphas have been pre-multiplied
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vtkm::Float32 alpha = (1.f - color[3]);
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color[0] = color[0] + inColor[0] * alpha;
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color[1] = color[1] + inColor[1] * alpha;
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color[2] = color[2] + inColor[2] * alpha;
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color[3] = inColor[3] * alpha + color[3];
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// clamp
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for (vtkm::Int32 i = 0; i < 4; ++i)
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{
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color[i] = vtkm::Min(1.f, vtkm::Max(color[i], 0.f));
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}
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// The existing depth should already been feed into the ray mapper
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// so no color contribution will exist past the existing depth.
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depthBuffer.Set(pixelIndex, depth);
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colorBuffer.Set(pixelIndex, color);
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}
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}; //class SurfaceConverter
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template <typename Precision>
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VTKM_CONT void WriteToCanvas(const vtkm::rendering::raytracing::Ray<Precision>& rays,
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const vtkm::cont::ArrayHandle<Precision>& colors,
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const vtkm::rendering::Camera& camera,
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vtkm::rendering::CanvasRayTracer* canvas)
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{
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vtkm::Matrix<vtkm::Float32, 4, 4> viewProjMat =
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vtkm::MatrixMultiply(camera.CreateProjectionMatrix(canvas->GetWidth(), canvas->GetHeight()),
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camera.CreateViewMatrix());
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vtkm::worklet::DispatcherMapField<SurfaceConverter>(SurfaceConverter(viewProjMat))
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.Invoke(rays.PixelIdx,
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colors,
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rays.Distance,
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rays.Origin,
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rays.Dir,
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canvas->GetDepthBuffer(),
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canvas->GetColorBuffer());
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//Force the transfer so the vectors contain data from device
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canvas->GetColorBuffer().WritePortal().Get(0);
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canvas->GetDepthBuffer().WritePortal().Get(0);
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}
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} // namespace internal
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CanvasRayTracer::CanvasRayTracer(vtkm::Id width, vtkm::Id height)
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: Canvas(width, height)
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{
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}
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CanvasRayTracer::~CanvasRayTracer() {}
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void CanvasRayTracer::WriteToCanvas(const vtkm::rendering::raytracing::Ray<vtkm::Float32>& rays,
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const vtkm::cont::ArrayHandle<vtkm::Float32>& colors,
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const vtkm::rendering::Camera& camera)
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{
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internal::WriteToCanvas(rays, colors, camera, this);
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}
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void CanvasRayTracer::WriteToCanvas(const vtkm::rendering::raytracing::Ray<vtkm::Float64>& rays,
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const vtkm::cont::ArrayHandle<vtkm::Float64>& colors,
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const vtkm::rendering::Camera& camera)
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{
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internal::WriteToCanvas(rays, colors, camera, this);
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}
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vtkm::rendering::Canvas* CanvasRayTracer::NewCopy() const
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{
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return new vtkm::rendering::CanvasRayTracer(*this);
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}
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}
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}
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