| 1 | // Created on: 2016-06-16 |
| 2 | // Created by: Denis BOGOLEPOV & Danila ULYANOV |
| 3 | // Copyright (c) 2016 OPEN CASCADE SAS |
| 4 | // |
| 5 | // This file is part of Open CASCADE Technology software library. |
| 6 | // |
| 7 | // This library is free software; you can redistribute it and/or modify it under |
| 8 | // the terms of the GNU Lesser General Public License version 2.1 as published |
| 9 | // by the Free Software Foundation, with special exception defined in the file |
| 10 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
| 11 | // distribution for complete text of the license and disclaimer of any warranty. |
| 12 | // |
| 13 | // Alternatively, this file may be used under the terms of Open CASCADE |
| 14 | // commercial license or contractual agreement. |
| 15 | |
| 16 | #ifndef _OpenGl_TileSampler_H |
| 17 | #define _OpenGl_TileSampler_H |
| 18 | |
| 19 | #include <OpenGl_Texture.hxx> |
| 20 | #include <OpenGl_HaltonSampler.hxx> |
| 21 | |
| 22 | #include <vector> |
| 23 | |
| 24 | //! Tool object used for sampling screen tiles according to estimated pixel variance (used in path tracing engine). |
| 25 | //! To improve GPU thread coherency, render window is split into pixel blocks or tiles. |
| 26 | class OpenGl_TileSampler |
| 27 | { |
| 28 | public: |
| 29 | |
| 30 | //! Size of individual tile in pixels. |
| 31 | static int TileSize() { return 32; } |
| 32 | |
| 33 | public: |
| 34 | |
| 35 | //! Creates new tile sampler. |
| 36 | Standard_EXPORT OpenGl_TileSampler(); |
| 37 | |
| 38 | //! Returns width of ray-tracing viewport. |
| 39 | int SizeX() const { return mySizeX; } |
| 40 | |
| 41 | //! Returns height of ray-tracing viewport. |
| 42 | int SizeY() const { return mySizeY; } |
| 43 | |
| 44 | //! Returns number of tiles in X dimension. |
| 45 | int NbTilesX() const { return myTilesX; } |
| 46 | |
| 47 | //! Returns number of tiles in Y dimension. |
| 48 | int NbTilesY() const { return myTilesY; } |
| 49 | |
| 50 | //! Returns total number of tiles in viewport. |
| 51 | int NbTiles() const { return myTilesX * myTilesY; } |
| 52 | |
| 53 | //! Specifies size of ray-tracing viewport. |
| 54 | Standard_EXPORT void SetSize (const int theSizeX, |
| 55 | const int theSizeY); |
| 56 | |
| 57 | //! Returns number of pixels in the given tile. |
| 58 | int TileArea (const int theX, |
| 59 | const int theY) const |
| 60 | { |
| 61 | return Min (TileSize(), mySizeX - theX * TileSize()) |
| 62 | * Min (TileSize(), mySizeY - theY * TileSize()); |
| 63 | } |
| 64 | |
| 65 | //! Fetches current error estimation from the GPU and |
| 66 | //! builds 2D discrete distribution for tile sampling. |
| 67 | Standard_EXPORT void GrabVarianceMap (const Handle(OpenGl_Context)& theContext); |
| 68 | |
| 69 | //! Samples tile location according to estimated error. |
| 70 | Standard_EXPORT void Sample (int& theOffsetX, |
| 71 | int& theOffsetY); |
| 72 | |
| 73 | //! Resets tile sampler to initial state. |
| 74 | void Reset() { mySample = 0; } |
| 75 | |
| 76 | //! Uploads offsets of sampled tiles to the given OpenGL texture. |
| 77 | Standard_EXPORT void Upload (const Handle(OpenGl_Context)& theContext, |
| 78 | const Handle(OpenGl_Texture)& theTexture, |
| 79 | bool theAdaptive); |
| 80 | |
| 81 | protected: |
| 82 | |
| 83 | //! Returns tile value (estimated error). |
| 84 | float Tile (const int theX, |
| 85 | const int theY) const |
| 86 | { |
| 87 | return myVarianceMap[theY * myTilesX + theX]; |
| 88 | } |
| 89 | |
| 90 | //! Returns tile value (estimated error). |
| 91 | float& ChangeTile (const int theX, |
| 92 | const int theY) |
| 93 | { |
| 94 | return myVarianceMap[theY * myTilesX + theX]; |
| 95 | } |
| 96 | |
| 97 | protected: |
| 98 | |
| 99 | std::vector<float> myVarianceMap; //!< Estimation of visual error per tile |
| 100 | std::vector<float> myMarginalMap; //!< Marginal distribution of 2D error map |
| 101 | OpenGl_HaltonSampler mySampler; //!< Halton sequence generator |
| 102 | int mySample; //!< Index of generated sample |
| 103 | int mySizeX; //!< Width of ray-tracing viewport |
| 104 | int mySizeY; //!< Height of ray-tracing viewport |
| 105 | int myTilesX; //!< Number of tiles in X dimension |
| 106 | int myTilesY; //!< Number of tiles in Y dimension |
| 107 | |
| 108 | }; |
| 109 | |
| 110 | #endif // _OpenGl_TileSampler_H |