1 | /* |
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2 | ----------------------------------------------------------------------------- |
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3 | This source file is part of OGRE |
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4 | (Object-oriented Graphics Rendering Engine) |
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5 | For the latest info, see http://www.ogre3d.org/ |
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6 | |
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7 | Copyright (c) 2000-2013 Torus Knot Software Ltd |
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8 | |
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9 | Permission is hereby granted, free of charge, to any person obtaining a copy |
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10 | of this software and associated documentation files (the "Software"), to deal |
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11 | in the Software without restriction, including without limitation the rights |
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12 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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13 | copies of the Software, and to permit persons to whom the Software is |
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14 | furnished to do so, subject to the following conditions: |
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15 | |
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16 | The above copyright notice and this permission notice shall be included in |
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17 | all copies or substantial portions of the Software. |
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18 | |
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19 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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20 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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21 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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22 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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23 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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24 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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25 | THE SOFTWARE. |
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26 | ----------------------------------------------------------------------------- |
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27 | */ |
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28 | #ifndef __FrameListener_H__ |
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29 | #define __FrameListener_H__ |
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30 | |
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31 | |
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32 | #include "OgrePrerequisites.h" |
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33 | |
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34 | namespace Ogre { |
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35 | |
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36 | /** \addtogroup Core |
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37 | * @{ |
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38 | */ |
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39 | /** \addtogroup General |
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40 | * @{ |
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41 | */ |
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42 | /** Struct containing information about a frame event. |
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43 | */ |
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44 | struct FrameEvent |
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45 | { |
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46 | /** Elapsed time in seconds since the last event. |
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47 | This gives you time between frame start & frame end, |
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48 | and between frame end and next frame start. |
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49 | @remarks |
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50 | This may not be the elapsed time but the average |
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51 | elapsed time between recently fired events. |
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52 | */ |
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53 | Real timeSinceLastEvent; |
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54 | /** Elapsed time in seconds since the last event of the same type, |
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55 | i.e. time for a complete frame. |
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56 | @remarks |
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57 | This may not be the elapsed time but the average |
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58 | elapsed time between recently fired events of the same type. |
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59 | */ |
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60 | Real timeSinceLastFrame; |
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61 | }; |
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62 | |
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63 | |
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64 | /** A interface class defining a listener which can be used to receive |
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65 | notifications of frame events. |
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66 | @remarks |
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67 | A 'listener' is an interface designed to be called back when |
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68 | particular events are called. This class defines the |
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69 | interface relating to frame events. In order to receive |
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70 | notifications of frame events, you should create a subclass of |
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71 | FrameListener and override the methods for which you would like |
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72 | to customise the resulting processing. You should then call |
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73 | Root::addFrameListener passing an instance of this class. |
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74 | There is no limit to the number of frame listeners you can register, |
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75 | allowing you to register multiple listeners for different purposes. |
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76 | Note that a frame event occurs once for all rendering targets, |
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77 | not once per target. |
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78 | */ |
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79 | class _OgreExport FrameListener |
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80 | { |
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81 | /* |
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82 | Note that this could have been an abstract class, but I made |
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83 | the explicit choice not to do this, because I wanted to give |
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84 | people the option of only implementing the methods they wanted, |
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85 | rather than having to create 'do nothing' implementations for |
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86 | those they weren't interested in. As such this class follows |
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87 | the 'Adapter' classes in Java rather than pure interfaces. |
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88 | */ |
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89 | public: |
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90 | /** Called when a frame is about to begin rendering. |
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91 | @remarks |
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92 | This event happens before any render targets have begun updating. |
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93 | @return |
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94 | True to go ahead, false to abort rendering and drop |
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95 | out of the rendering loop. |
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96 | */ |
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97 | virtual bool frameStarted(const FrameEvent& evt) |
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98 | { (void)evt; return true; } |
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99 | |
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100 | /** Called after all render targets have had their rendering commands |
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101 | issued, but before render windows have been asked to flip their |
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102 | buffers over. |
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103 | @remarks |
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104 | The usefulness of this event comes from the fact that rendering |
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105 | commands are queued for the GPU to process. These can take a little |
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106 | while to finish, and so while that is happening the CPU can be doing |
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107 | useful things. Once the request to 'flip buffers' happens, the thread |
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108 | requesting it will block until the GPU is ready, which can waste CPU |
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109 | cycles. Therefore, it is often a good idea to use this callback to |
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110 | perform per-frame processing. Of course because the frame's rendering |
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111 | commands have already been issued, any changes you make will only |
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112 | take effect from the next frame, but in most cases that's not noticeable. |
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113 | @return |
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114 | True to continue rendering, false to drop out of the rendering loop. |
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115 | */ |
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116 | virtual bool frameRenderingQueued(const FrameEvent& evt) |
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117 | { (void)evt; return true; } |
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118 | |
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119 | /** Called just after a frame has been rendered. |
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120 | @remarks |
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121 | This event happens after all render targets have been fully updated |
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122 | and the buffers switched. |
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123 | @return |
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124 | True to continue with the next frame, false to drop |
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125 | out of the rendering loop. |
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126 | */ |
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127 | virtual bool frameEnded(const FrameEvent& evt) |
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128 | { (void)evt; return true; } |
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129 | |
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130 | virtual ~FrameListener() {} |
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131 | |
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132 | }; |
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133 | /** @} */ |
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134 | /** @} */ |
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135 | } |
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136 | |
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137 | #endif |
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