参考自:https://en.wikibooks.org/wiki/GLSL_Programming/Unity/Soft_Shadows_of_Spheres
using UnityEngine; using System.Collections; [ExecuteInEditMode] public class TestShadowOfSphere : MonoBehaviour { public GameObject occluder; // Use this for initialization void Start () { } // Update is called once per frame void Update () { if (null != occluder) { GetComponent<Renderer>().sharedMaterial.SetVector("_SpherePosition", occluder.transform.position); GetComponent<Renderer>().sharedMaterial.SetFloat("_SphereRadius", occluder.transform.localScale.x / 2.0f); } } }
Shader "Cg shadow of sphere" { Properties{ _Color("Diffuse Material Color", Color) = (1,1,1,1) _SpecColor("Specular Material Color", Color) = (1,1,1,1) _Shininess("Shininess", Float) = 10 _SpherePosition("Sphere Position", Vector) = (0,0,0,1) _SphereRadius("Sphere Radius", Float) = 1 _LightSourceRadius("Light Source Radius", Float) = 0.005 } SubShader{ Pass{ Tags{ "LightMode" = "ForwardBase" } // pass for ambient light and first light source CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma target 3.0 #include "UnityCG.cginc" uniform float4 _LightColor0; // color of light source (from "Lighting.cginc") // User-specified properties uniform float4 _Color; uniform float4 _SpecColor; uniform float _Shininess; uniform float4 _SpherePosition; // center of shadow-casting sphere in world coordinates uniform float _SphereRadius; // radius of shadow-casting sphere uniform float _LightSourceRadius; // in radians for directional light sources struct vertexInput { float4 vertex : POSITION; float3 normal : NORMAL; }; struct vertexOutput { float4 pos : SV_POSITION; float4 posWorld : TEXCOORD0; float3 normalDir : TEXCOORD1; }; vertexOutput vert(vertexInput input){ vertexOutput output; float4x4 modelMatrix = _Object2World; float4x4 modelMatrixInverse = _World2Object; output.posWorld = mul(modelMatrix, input.vertex); output.normalDir = normalize( mul(float4(input.normal, 0.0), modelMatrixInverse).xyz); output.pos = mul(UNITY_MATRIX_MVP, input.vertex); return output; } float4 frag(vertexOutput input) : COLOR{ float3 normalDirection = normalize(input.normalDir); float3 viewDirection = normalize( _WorldSpaceCameraPos - input.posWorld.xyz); float3 lightDirection; float lightDistance; float attenuation; if (0.0 == _WorldSpaceLightPos0.w) // directional light? { attenuation = 1.0; // no attenuation lightDirection = normalize(_WorldSpaceLightPos0.xyz); lightDistance = 1.0; } else // point or spot light { lightDirection = _WorldSpaceLightPos0.xyz - input.posWorld.xyz; lightDistance = length(lightDirection); attenuation = 1.0 / lightDistance; // linear attenuation lightDirection = lightDirection / lightDistance; } // computation of level of shadowing w float3 sphereDirection = _SpherePosition.xyz - input.posWorld.xyz; float sphereDistance = length(sphereDirection); sphereDirection = sphereDirection / sphereDistance; float d = lightDistance * (asin(min(1.0, length(cross(lightDirection, sphereDirection)))) - asin(min(1.0, _SphereRadius / sphereDistance))); float w = smoothstep(-1.0, 1.0, -d / _LightSourceRadius); w = w * smoothstep(0.0, 0.2, dot(lightDirection, sphereDirection)); if (0.0 != _WorldSpaceLightPos0.w) // point light source? { w = w * smoothstep(0.0, _SphereRadius, lightDistance - sphereDistance); } float3 ambientLighting = UNITY_LIGHTMODEL_AMBIENT.rgb * _Color.rgb; float3 diffuseReflection = attenuation * _LightColor0.rgb * _Color.rgb * max(0.0, dot(normalDirection, lightDirection)); float3 specularReflection; if (dot(normalDirection, lightDirection) < 0.0) // light source on the wrong side? { specularReflection = float3(0.0, 0.0, 0.0); // no specular reflection } else // light source on the right side { specularReflection = attenuation * _LightColor0.rgb * _SpecColor.rgb * pow(max(0.0, dot( reflect(-lightDirection, normalDirection), viewDirection)), _Shininess); } return float4(ambientLighting + (1.0 - w) * (diffuseReflection + specularReflection), 1.0); } ENDCG } Pass{ Tags{ "LightMode" = "ForwardAdd" } // pass for additional light sources Blend One One // additive blending CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma target 3.0 #include "UnityCG.cginc" uniform float4 _LightColor0; // color of light source (from "Lighting.cginc") // User-specified properties uniform float4 _Color; uniform float4 _SpecColor; uniform float _Shininess; uniform float4 _SpherePosition; // center of shadow-casting sphere in world coordinates uniform float _SphereRadius; // radius of shadow-casting sphere uniform float _LightSourceRadius; // in radians for directional light sources struct vertexInput { float4 vertex : POSITION; float3 normal : NORMAL; }; struct vertexOutput { float4 pos : SV_POSITION; float4 posWorld : TEXCOORD0; float3 normalDir : TEXCOORD1; }; vertexOutput vert(vertexInput input) { vertexOutput output; float4x4 modelMatrix = _Object2World; float4x4 modelMatrixInverse = _World2Object; output.posWorld = mul(modelMatrix, input.vertex); output.normalDir = normalize( mul(float4(input.normal, 0.0), modelMatrixInverse).xyz); output.pos = mul(UNITY_MATRIX_MVP, input.vertex); return output; } float4 frag(vertexOutput input) : COLOR { float3 normalDirection = normalize(input.normalDir); float3 viewDirection = normalize( _WorldSpaceCameraPos - input.posWorld.xyz); float3 lightDirection; float lightDistance; float attenuation; if (0.0 == _WorldSpaceLightPos0.w) // directional light? { attenuation = 1.0; // no attenuation lightDirection = normalize(_WorldSpaceLightPos0.xyz); lightDistance = 1.0; } else // point or spot light { lightDirection = _WorldSpaceLightPos0.xyz - input.posWorld.xyz; lightDistance = length(lightDirection); attenuation = 1.0 / lightDistance; // linear attenuation lightDirection = lightDirection / lightDistance; } // computation of level of shadowing w float3 sphereDirection = _SpherePosition.xyz - input.posWorld.xyz; float sphereDistance = length(sphereDirection); sphereDirection = sphereDirection / sphereDistance; float d = lightDistance * (asin(min(1.0, length(cross(lightDirection, sphereDirection)))) - asin(min(1.0, _SphereRadius / sphereDistance))); float w = smoothstep(-1.0, 1.0, -d / _LightSourceRadius); w = w * smoothstep(0.0, 0.2, dot(lightDirection, sphereDirection)); if (0.0 != _WorldSpaceLightPos0.w) // point light source? { w = w * smoothstep(0.0, _SphereRadius, lightDistance - sphereDistance); } float3 diffuseReflection = attenuation * _LightColor0.rgb * _Color.rgb * max(0.0, dot(normalDirection, lightDirection)); float3 specularReflection; if (dot(normalDirection, lightDirection) < 0.0) // light source on the wrong side? { specularReflection = float3(0.0, 0.0, 0.0); // no specular reflection } else // light source on the right side { specularReflection = attenuation * _LightColor0.rgb * _SpecColor.rgb * pow(max(0.0, dot( reflect(-lightDirection, normalDirection), viewDirection)), _Shininess); } return float4((1.0 - w) * (diffuseReflection + specularReflection), 1.0); } ENDCG } } Fallback "Specular" }