关于unity的shader,gpu动画
/*
Created by jiadong chen
https://jiadong-chen.medium.com/
*/
Shader "chenjd/BuiltIn/AnimMapShader"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_AnimTex ("Texture", 2D) = "white" {}
_AnimTime ("AnimTime", float) = 1
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Pass
{
CGPROGRAM
#pragma target 3.5
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_instancing
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
uint vid : SV_VERTEXID;
UNITY_VERTEX_INPUT_INSTANCE_ID
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
UNITY_VERTEX_INPUT_INSTANCE_ID
};
CBUFFER_START(UnityPerMaterial)
sampler2D _MainTex;
sampler2D _AnimTex;
UNITY_INSTANCING_BUFFER_START(Props)
UNITY_DEFINE_INSTANCED_PROP(float4, _AnimTex_TexelSize)
UNITY_DEFINE_INSTANCED_PROP(float4, _MainTex_ST)
UNITY_DEFINE_INSTANCED_PROP(float, _AnimTime)
UNITY_INSTANCING_BUFFER_END(Props)
CBUFFER_END
v2f vert (appdata v)
{
v2f o;
UNITY_SETUP_INSTANCE_ID(v);
UNITY_TRANSFER_INSTANCE_ID(v, o);
float4 uv_anim = float4((v.vid + 0.5) * UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTex_TexelSize).x, _Time.y / UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0);
v.vertex = float4(tex2Dlod(_AnimTex, uv_anim).xyz,1.0);
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = v.uv * UNITY_ACCESS_INSTANCED_PROP(Props, _MainTex_ST).xy + UNITY_ACCESS_INSTANCED_PROP(Props, _MainTex_ST).zw;
return o;
}
fixed4 frag (v2f i) : SV_Target
{
UNITY_SETUP_INSTANCE_ID(i);
fixed4 col = tex2D(_MainTex, i.uv);
return col;
}
ENDCG
}
}
}
如果我要动态改变动画。
float4 uv_anim = float4((v.vid + 0.5) * UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTex_TexelSize).x, _Time.y / UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0);
这里 _Time.y / UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0);应该是取动画的进度。但是这个时间是一直在走的。那么动画如何才能每次都从0帧开始播放呢?我在游戏场景里调试,发现有时动画不是从头开始播放的。