[游戏开发]Unity 血条Shader（一）

按角色血量改变血条

 Shader "Unlit/HpBarShader"
{
    Properties
    {
        [NoScaleoffset]_MainTex ("Texture", 2D) = "white" {}
		_Health ("Health", Range(0, 1)) = 1
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct MeshData
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct Interpolator
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
			float _Health;

            Interpolator vert (MeshData v)
            {
                Interpolator o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o; 
            }

			float InverseLerp(float a, float b, float v)
			{
				return (v - a) / (b - a);
			}

			float4 frag(Interpolator i) : SV_Target
            {
                //fixed4 col = tex2D(_MainTex, i.uv);

				float healthMask = _Health > i.uv.x;//floor(i.uv.x * 8) / 8;血条分段减少
				//clip(healthMask - 1);//裁剪（裁剪掉失去量部分）， 使bg变为透明,(一般情况剪的越早越好)。
				
				float tHealthColor = InverseLerp(0.3, 0.7, _Health);//0->0.3 = red, 0.7->1 = green，颜色渐变阈值
				float3 healthColor = lerp(float3(1, 0 , 0), float3(0 , 1, 0), tHealthColor); //_Health);//颜色渐变融合
				//return float4(healthColor, 0);
				
				float3 bgColor = float3(0, 0, 0);//底颜色
				float3 outColor = lerp(bgColor, healthColor, healthMask);//healthMask遮罩融合
				return float4(outColor, 0);
            }
            ENDCG
        }
    }
}