1 | /* -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ |
---|

2 | /* |
---|

3 | * Copyright (c) 2004-2013 HUBzero Foundation, LLC |
---|

4 | * |
---|

5 | * Authors: |
---|

6 | * Wei Qiao <qiaow@purdue.edu> |
---|

7 | */ |
---|

8 | |
---|

9 | // update velocity based on acceleration |
---|

10 | |
---|

11 | #include "common.cg" |
---|

12 | |
---|

13 | float4 main(in float2 uv : TEXCOORD0, |
---|

14 | uniform samplerRECT pos_tex, |
---|

15 | uniform samplerRECT vel_tex, |
---|

16 | uniform sampler2D terrain_tex, |
---|

17 | uniform float timestep = 0.01, |
---|

18 | uniform float damping = 0.99, |
---|

19 | uniform float3 gravity = float3(0, -1, 0), |
---|

20 | uniform float3 spherePos, |
---|

21 | uniform float3 sphereVel) : COLOR |
---|

22 | { |
---|

23 | const float3 terrain_scale = float3(8.0, 2.0, 8.0); |
---|

24 | const float3 terrain_offset = float3(-4.0, 0.01, -4.0); |
---|

25 | |
---|

26 | float3 pos = texRECT(pos_tex, uv).xyz; |
---|

27 | float3 vel = texRECT(vel_tex, uv).xyz; |
---|

28 | |
---|

29 | float3 pos_next = pos + vel * timestep; // predicted position next timestep |
---|

30 | |
---|

31 | float3 force = gravity; |
---|

32 | // float3 force = 0.0; |
---|

33 | // Gravitation(pos, spherePos, force, 0.1); |
---|

34 | |
---|

35 | SphereCollide(pos_next, vel, spherePos, 1.0, sphereVel, 0.5, force); |
---|

36 | // FloorCollide(pos_next, vel, 0.0, 0.5, force); |
---|

37 | TerrainCollide(pos_next, vel, terrain_tex, terrain_scale, terrain_offset, 0.5); |
---|

38 | |
---|

39 | const float inv_mass = 1.0; |
---|

40 | vel += force * inv_mass * timestep; // F = ma |
---|

41 | vel *= damping; |
---|

42 | |
---|

43 | return float4(vel, 1.0); |
---|

44 | } |
---|