添加实时阴影

For the sake of anyone else who is trying to write a fragment shader that receives shadows, I figured it out.

You must do these things:

1. '#include "AutoLight.cginc"'
2. '#include "Lighting.cginc"'
3. Add "Tags {"LightMode" = "ForwardBase"}
4. '#pragma multi_compile_fwdbase'
5. Add the Unity macros to your VSOut struct, VS and PS: LIGHTING_COORDS, TRANSFER_VERTEX_TO_FRAGMENT, LIGHT_ATTENUATION.

None of this is documented in the Unity manual.

To access the primary directional light color, unity_LightColor[0] works as long as you don't add "Tags {"LightMode" = "ForwardBase"}". If you do add that line, then it doesn't work: use _LightColor0.rgb instead. Why? Who knows.. probably makes sense to someone with access to the Unity source code. Which means no one.

Good luck!

-Peter

1. Shader "Custom/PeterShader2" {
2. Properties
3. {
4. _MainTex ("Base (RGB)", 2D) = "white" {}
5. }
6.  
7. CGINCLUDE
8.  
9. #include "UnityCG.cginc"
10. #include "AutoLight.cginc"
11. #include "Lighting.cginc"
12.  
13. uniform sampler2D _MainTex;
14.  
15. ENDCG
16.  
17. SubShader
18. {
19. Tags { "RenderType"="Opaque" }
20. LOD 200
21.  
22. Pass
23. {
24. Lighting On
25.  
26. Tags {"LightMode" = "ForwardBase"}
27.  
28. CGPROGRAM
29.  
30. #pragma vertex vert
31. #pragma fragment frag
32. #pragma multi_compile_fwdbase
33.  
34. struct VSOut
35. {
36. float4 pos : SV_POSITION;
37. float2 uv : TEXCOORD1;
38. LIGHTING_COORDS(3,4)
39. };
40.  
41. VSOut vert(appdata_tan v)
42. {
43. VSOut o;
44. o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
45. o.uv = v.texcoord.xy;
46.  
47. TRANSFER_VERTEX_TO_FRAGMENT(o);
48.  
49. return o;
50. }
51.  
52. float4 frag(VSOut i) : COLOR
53. {
54. float3 lightColor = _LightColor0.rgb;
55. float3 lightDir = _WorldSpaceLightPos0;
56. float4 colorTex = tex2D(_MainTex, i.uv.xy * float2(25.0f));
57. float atten = LIGHT_ATTENUATION(i);
58. float3 N = float3(0.0f, 1.0f, 0.0f);
59. float NL = saturate(dot(N, lightDir));
60.  
61. float3 color = colorTex.rgb * lightColor * NL * atten;
62. return float4(color, colorTex.a);
63. }
64.  
65. ENDCG
66. }
67. }
68. FallBack "Diffuse"
69. }