PSSM and deferred shading (unfilled shadow)

akira32

I meet a problem about using PSSM(Parallel-Split Shadow Maps) to render the shadow to a shadow result texture (restore the shadow pixel, 1 means lighted, 0 means shadowed). The shadow result texture is a render target texture with the format of R32F. My problem is that if I render a flag model in PS_SRT (pixel shader to generate shadow result texture) and using "return fLightingFactor;", I will see the nofilled shadow. If I using "return float4(fLightingFactor,1.0f,1.0f,1.0f);" in PS_SRT, I will see the filled shadow.

The filled shadow: http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/Questions/shadow/PSSM%7C_shadow%7C_fill.JPG
The unfilled shadow: http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/Questions/shadow/PSSM%7C_shadow%7C_notfill.JPG

The filled shadow also has a stranger aliasing problem. The program is written by my lowerclassman. I implement PSSM into this program. I also implement the PSSM into my MapEditor, but my MapEditor has no this stranger shadow aliasing and no unfilled problem---no matter the return statement ("return fLightingFactor;" or "return float4(fLightingFactor,1.0f,1.0f,1.0f);" ).(My MapEditor's flag shadow : http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/Questions/shadow/PSSM%7C_shadow%7C_fill%7C_ME%7C_no%7C_aliasing.JPG).

These are my partial shader code:

1. 
   
2. void VS_RenderShadowMap(
   
3.                                                 float4 vPos : POSITION,
   
4.                                                 out float4 vPosOut : POSITION,
   
5.                                                 out float3 vPixelOut : TEXCOORD0)
   
6. {
   
7.         // pass vertex position through as usual
   
8.         vPosOut = mul(vPos, wvp);
   
9.         // output pixel pos
   
10.         vPixelOut=vPosOut.xyz;
    
11. }
    
12. 
    
13. float4 PS_RenderShadowMap(float3 vPixelPos : TEXCOORD0): COLOR
    
14. {
    
15.         // write z coordinate (linearized depth) to texture
    
16.         return vPixelPos.z;
    
17. }
    
18. 
    
19. 
    
20. // This technique is used when rendering meshes to the shadowmap
    
21. //
    
22. technique RenderShadowMap
    
23. {
    
24.         pass p0
    
25.         {
    
26.                 // render back faces to hide artifacts
    
27.                 CullMode = CW;
    
28.                 ZWriteEnable=TRUE;
    
29.                 ZEnable=TRUE;
    
30.                 VertexShader = compile vs_3_0 VS_RenderShadowMap();
    
31.                 PixelShader = compile ps_3_0 PS_RenderShadowMap();
    
32.         }
    
33. }
    
34. 
    
35. void VS_SRT(
    
36.                         in float4 vPos : POSITION,
    
37.                         in float3 vNormal : NORMAL,
    
38.                         in float4 vDiffuseTex : TEXCOORD0,
    
39.                         out float4 vPosOut : POSITION,
    
40.                         out float4 vShadowTex : TEXCOORD0,
    
41.                         out float4 vDiffuseTexOut : TEXCOORD1
    
42.                         )
    
43. {
    
44.         // pass vertex position through as usual
    
45.         vPosOut = mul(vPos, wvp);
    
46. 
    
47.         // coordinates for shadowmap
    
48.         vShadowTex = mul(vPos, g_mShadowMap);
    
49.         vDiffuseTexOut=vDiffuseTex;
    
50. }
    
51. 
    
52. float4 PS_SRT(
    
53.                           float4 vShadowTex : TEXCOORD0,
    
54.                           float4 vDiffuseTex: TEXCOORD1
    
55.                           ) : COLOR
    
56. {
    
57. 
    
58.         float4 Color=tex2D(DiffuseMapSampler1, vDiffuseTex);
    
59.         if (Color.a<0.5f)
    
60.         {
    
61.                 discard;
    
62.         }
    
63.        
    
64.         //float fTexelSize=1.0f/g_fShadowMapSize;
    
65. 
    
66.         // project texture coordinates
    
67.         vShadowTex.xy/=vShadowTex.w;
    
68. 
    
69. .......
    
70.         if (g_bUseColorfulSplit==true)
    
71.         {
    
72. .......
    
73. 
    
74. #ifdef _RETURN_FLOAT4_
    
75.                 return float4(fLightingFactor,1.0f,1.0f,1.0f);
    
76. #else
    
77.                 return fLightingFactor;
    
78. #endif
    
79.         }
    
80.        
    
81. }
    
82. 
    
83. technique generateSRT
    
84. {
    
85.         pass p0
    
86.         {
    
87.                 // render front faces
    
88.                 //CullMode = CCW;
    
89.                 CullMode=CCW;
    
90.                 ZWriteEnable=TRUE;
    
91.                 ZEnable=TRUE;               
    
92.                        
    
93.                 VertexShader = compile vs_3_0 VS_SRT();
    
94.                 PixelShader = compile ps_3_0 PS_SRT();
    
95.         }
    
96. }
    

复制代码

yuhongyi

If your map editor and game share share the same shader, most likely your shader is correct.  You should check whether you have passed in some wrong parameters.  It seems to be difficult to figure out the root cause of the aliasing.  I recommend you debug it with PIX.