基础光照部分

环境光

在标准光照模型中，我们会环境光来代替间接光照

Cambient = g amient

我们可以在Windows->Rendering->Lighting->Enviroment进行修改Ambient 的Color

自发光

直接在最后片元着色器输出颜色之前把材质的自发光颜色添加到输出颜色上就行了

漫反射光照模型

为了缩短文章篇幅，因此我就只在片元着色器上计算光照，不考虑高洛德着色

n代表法向量，I代表光源反向(注意方向是否需要取反)

兰伯特模型

		v2f vert(a2v v) {
				v2f o;
				// Transform the vertex from object space to projection space
				o.pos = UnityObjectToClipPos(v.vertex);

				// Transform the normal from object space to world space
				o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);

				return o;
			}
			
			fixed4 frag(v2f i) : SV_Target {
				// Get ambient term
				fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;
				
				// Get the normal in world space
				fixed3 worldNormal = normalize(i.worldNormal);
				// Get the light direction in world space
				fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
				
				// Compute diffuse term
				fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, worldLightDir));
				
				fixed3 color = ambient + diffuse;
				
				return fixed4(color, 1.0);
			}

实现效果如下

半兰伯特模型

		v2f vert(a2v v) {
				v2f o;
				// Transform the vertex from object space to projection space
				o.pos = UnityObjectToClipPos(v.vertex);
				
				// Transform the normal from object space to world space
				o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);
				
				return o;
			}
			
			fixed4 frag(v2f i) : SV_Target {
				// Get ambient term
				fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;
				
				// Get the normal in world space
				fixed3 worldNormal = normalize(i.worldNormal);
				// Get the light direction in world space
				fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
				
				// Compute diffuse term
				fixed halfLambert = dot(worldNormal, worldLightDir) * 0.5 + 0.5;
				fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * halfLambert;
				
				fixed3 color = ambient + diffuse;
				
				return fixed4(color, 1.0);
			}

实现效果如下