source: GTP/trunk/App/Demos/Illum/Hierarchical Systems Demo [OpenGL]/src/AdvancedParticleSystem.h @ 858

Revision 858, 5.3 KB checked in by szirmay, 19 years ago (diff)
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1#pragma once
2#include <My3DGraphRes/ParticleSystem.h>
3#include <My3DGraphRes/Texture.h>
4#include <My3DGraphRes/Impostor.h>
5#include <RttRes/RenderTexture.h>
6#include <MyCgRes/CgProgram.h>
7#include <My3DGraphRes/Scene.h>
8#include <My3DGraphRes/ThirdPersonCamera.h>
9
10/**
11        @brief Implements a hierarchical particle system.
12
13        A hierarchical particle system is a particle system made out of a smaller particle systems.
14        First an image of the smaller particle system should be rendered, than this image can be multiplied
15        and be used as sprite images to form the bigger system.
16
17        To avoid incorrect depth culling caused by the simplifications made by considering a group of particles
18        as a single quad we have to take into acount some additional depth information too.
19        We also render the the closest and the furthest depth values of the smaller system in the view camera's space.
20        During display this depth information can be used to estimate the length of the light ray segment
21        travelled in the medium and alter the opacity of the particles respectively.
22
23        This particle system implementation also deals with light scattering inside the medium.
24        It builds a layered light absorption texture which stores the amount of absorped light in
25        different depths from lightsource. With the use of the illumination texture we can approximate self shadowing of the medium.
26        This implementation uses four layers and stores it in the four channels of a texture.
27        This way no 3D textures are needed, and the light absorption (illumination) texture can be generated in a single render pass.
28       
29        During rendering a mie scattering model is used to compute the amount of scattered light.
30        To speed up calculations phase function values are read back from a 2D look-up texture (phase texture).
31*/
32class AdvancedParticleSystem
33{
34public:
35        AdvancedParticleSystem(void);
36        ~AdvancedParticleSystem(void);
37
38private:
39        //!Impostor to display
40        Impostor m_DisplayImpostor;
41        //!Impostor for illumination calculation
42        Impostor m_IllumImpostor;
43
44        //not used
45        RenderTexture m_DisplayTexture;
46        //!Illumination texture
47        RenderTexture m_IllumTexture;
48        //! Stores nearest and furthest distances of the particles from the camera and also the opacity
49        RenderTexture m_FrontDepthTexture;
50        //not used
51        RenderTexture m_BackDepthTexture;
52        //! Stores nearest distances of the scene objects from the camera
53        RenderTexture m_ObjectsTexture;
54        //! A motion blurred version of the illumination texture to avoid abrupt changes
55        RenderTexture m_ScatteredIlumTexture;
56
57        //cg programs
58        CgProgram m_IllumProgram;
59        CgProgram m_FrontDepthProgram;
60        CgProgram m_DensityOnlyProgram;
61        CgProgram m_DisplayProgram;
62        CgProgram m_Psys_Depth_Multiple_Forward_Program;
63        CgProgram m_TempProg;CgProgram m_TempProg2;
64        CgProgram m_ObjDepthProg;
65        CgProgram m_ScatterIllumProgram;
66        CgProgram m_Psys_Multiple_Forward_Program;
67        CgProgram m_Psys_Single_Phase_Program;
68        CgProgram m_Psys_Depth_Single_Phase_Program;
69        CgProgram m_Psys_Depth_Default_Program;
70        CgProgram m_Psys_Default_Program;
71       
72        //Camera m_LightCamera;
73        ThirdPersonCamera m_LightCamera;
74
75        float* m_SceneTransformMatrix;
76       
77public:
78        bool m_HasSceneTransformMatrix;
79
80        Scene* theScene;
81        bool object_shadows;
82        bool depthcalc;
83        int m_PSys_RenderMode;
84        //! albedo of the particles
85        float albedo;
86        //! scattering symmetry of the scattering (used in phase function calculation)
87        float symmetry;
88        //only helper attribute
89        float symmetry2;
90        //! transparency of the particles
91        float transparency;
92        unsigned int PhaseTexID;
93        unsigned int AngleTexID;
94        Vector m_LightColor;
95        Vector m_LightPosition;
96
97        //! particle system made ot of a smaller system
98        ParticleSystem m_ParticleSystem;
99        //! smaller particle system
100        ParticleSystem m_LittleParticleSystem;
101
102        //Billboard display texture
103        Texture m_BillboardTexture;
104        Texture m_BbBackDepthTexture;
105        Texture m_BbFrontDepthTexture;
106
107        //! renders the particle system from the given camera using the given light position
108        void Display(Camera* cam,Vector LightPos);
109        //! refreshes the particle system
110        void Refresh(Camera* cam,
111                                Vector LightPos,
112                                unsigned int Dt,
113                                unsigned int TimefromSecond);
114        //! generates front and back depth textures od the smaller particle system
115        void RefreshDepths(Camera* cam);
116        //not used
117        void RefreshDepthswithSpheres(Camera* cam);
118        //! initialize textures and gpu programs
119        void Initialize();
120        //! initialize the two particle systems
121        void InitSystems();
122        //! generates scene depth texture
123        void RenderObjectDepths(Camera* cam);
124
125        //for debug
126        void displayillum(Camera* cam);
127        void displayLittle(Camera* cam);
128        void displaytexture(int tex);
129
130        /**
131                @brief refreshes the illumination texture
132       
133                The illumination texture is a four layered texture, each layer stored in the separate color channels.
134        */
135        void RefreshIllumTextures(Vector LightPos);
136
137        void DecreaseAlbedo(){albedo-=0.01;if(albedo<0)albedo=0;}
138        void IncreaseAlbedo(){albedo+=0.01;if(albedo>1)albedo=1;}
139        void DecreaseTransparency(){transparency-=0.05;if(transparency<0)transparency=0;}
140        void IncreaseTransparency(){transparency+=0.05;if(transparency>1)transparency=1;}
141        void DecreaseSymmetry(){symmetry-=0.01;if(symmetry<-1)symmetry=-1;}
142        void IncreaseSymmetry(){symmetry+=0.01;if(symmetry>1)symmetry=1;}
143
144        void setSceneTransformMatrix(float* matr){m_HasSceneTransformMatrix=true;m_SceneTransformMatrix=matr;}
145};
146
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