如何配置ARBMODE
⑴ 如何在unity3d中實現動態環境光的效果
在unity3d中實現動態環境光的效果，似乎可以用此方法來做出一天中不同時間的光線效果。
下面是原文：
I』ve been working on getting dynamic ambient lighting working
within Unity. Based off Valve』s 6-colour pre-baked ambient lighting
(detailed here, pg 5, ch 8.4.1), but it grabs the 6 colours
dynamically.
There』s probably lots more you could do to optimise it further
(e.g. use replacement shaders when rendering the cubemap that do
simpler lighting calcs). But you could do that yourself as
required.
I』d also advise against using it on anything other than your
main character, as it』s likely too expensive to run on multiple
objects.
cubemap camera script
Create a new camera and turn off the GUI, Flare and Audio
components.
Set up it』s Culling Layers to not render non-essential things
like particles or incidental detail. Also move your character to
it』s own layer and set the camera not to render it (we don』t want
bits of the character rendered into the cubemap).
Attach this javascript to it and set the target to be your
character and set up the offset from your character』s position so
that it』s in the centre of your character (i.e. a 2m tall character
wants to be offset 0, 1, 0 so that the camera renders from the
characters centre.
下面為攝像機腳本：
@script ExecuteInEditMode
public var target : Transform;
public var cubemapSize : int = 128;
public var oneFacePerFrame : boolean = true;
public var offset : Vector3 = Vector3.zero;
private var cam : Camera;
private var rtex : RenderTexture;
function Start () {
cam = camera;
cam.enabled = false;
// render all six faces at startup
UpdateCubemap( 63 );
transform.rotation = Quaternion.identity;
}
function LateUpdate () {
if (
oneFacePerFrame ) {
var faceToRender = Time.frameCount % 6;
var faceMask = 1 << faceToRender;
UpdateCubemap ( faceMask );
} else
{
UpdateCubemap ( 63 ); // all six faces
}
}
function UpdateCubemap ( faceMask : int ) {
if ( !rtex ) {
rtex = new RenderTexture ( cubemapSize, cubemapSize, 16 );
rtex.isPowerOfTwo = true;
rtex.isCubemap = true;
rtex.useMipMap = true;
rtex.hideFlags = HideFlags.HideAndDontSave;
rtex.SetGlobalShaderProperty ( " _ WorldCube" );
}
transform.position = target.position + offset;
cam.RenderToCubemap ( rtex, faceMask );
}
function OnDisable () {
DestroyImmediate ( rtex );
}
dynamic ambient shader
環境光shader
This is the shader that generates and applies the ambient
lighting from the cubemap rendered by the camera above.
Create a new shader, paste this code into it and save it. We』ll
integrate it into our shaders next.
下面是shader代碼：
Shader "DynamicAmbient" {
Properties {
_ MainTex ("Diffuse (RGB) Alpha (A)", 2D) = "white" {}
_ BumpMap ("Normal (Normal)", 2D) = "bump" {}
}
SubShader{
Pass {
Name "DynamicAmbient"
Tags {"LightMode" = "Always"}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB _ precision _ hint _ fastest
#include "UnityCG.cginc"
struct v2f
{
float4 pos : SV _ POSITION;
float2 uv : TEXCOORD0;
float3 normal : TEXCOORD2;
float3 tangent : TEXCOORD3;
float3 binormal : TEXCOORD4;
};
v2f vert (appdata _ tan v)
{
v2f o;
o.pos = mul(UNITY _ MATRIX _ MVP, v.vertex);
o.uv = v.texcoord.xy;
o.normal = mul( _ Object2World, float4(v.normal, 0)).xyz;
o.tangent = v.tangent.xyz;
o.binormal = cross(o.normal, o.tangent) * v.tangent.w;
return o;
}
sampler2D _ MainTex;
sampler2D _ BumpMap;
samplerCUBE _ WorldCube;
float4 frag(v2f i) : COLOR
{
fixed4 albedo = tex2D( _ MainTex, i.uv);
float3 normal = UnpackNormal(tex2D( _ BumpMap, i.uv));
float3 worldNormal = normalize((i.tangent * normal.x) +
(i.binormal * normal.y) + (i.normal * normal.z));
float3 nSquared = worldNormal * worldNormal;
fixed3 linearColor;
linearColor = nSquared.x * texCUBEbias( _ WorldCube,
float4(worldNormal.x, 0.00001, 0.00001, 999)).rgb; // For unknown
reasons, giving an absolute vector ignores the mips....
linearColor += nSquared.y * texCUBEbias( _ WorldCube,
float4(0.00001, worldNormal.y, 0.00001, 999)).rgb; // ...so unused
components must have a tiny, non-zero value in.
linearColor += nSquared.z * texCUBEbias( _ WorldCube,
float4(0.00001, 0.00001, worldNormal.z, 999)).rgb;
float4 c;
c.rgb = linearColor * albedo.rgb;
c.a = albedo.a;
return c;
}
ENDCG
}
}
FallBack Off
}
integrating the ambient shader into surface shaders
將環境光shader與物體表面的shader發生互相影響
Now, we can use the above shader wherever we want it via the
UsePass command, and blending everything else on top.
The key here is to ensure your surface shader』s blend mode is
set to additive (One One) otherwise it』ll just write clean over the
lovely ambient light that』s been applied.So, before your surface
shader』s CGPROGRAM block, add the lines;
添加shader代碼：
UsePass "DynamicAmbient/DYNAMICAMBIENT"
Blend One One
We』ve also got to ensure that our surface shader doesn』t use the
ambient light value that』s set in the editor, otherwise it』ll add
the two together and defeat the purpose. So when you define the
surface shader to use, ensure you add the noambient argument.
e.g;
#pragma surf BlinnPhong noambient
Your new surface shader with dynamic ambient lighting should
look something like this;
Shader "Bumped Specular" {
Properties {
_ Color ("Main Color", Color) = (1,1,1,1)
_ SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 1)
_ Shininess ("Shininess", Range (0.03, 1)) = 0.078125
_ MainTex ("Base (RGB) Gloss (A)", 2D) = "white" {}
_ BumpMap ("Normalmap", 2D) = "bump" {}
}
SubShader {
Tags { "RenderType"="Opaque" }
LOD 400
UsePass "DynamicAmbient/DYNAMICAMBIENT"
Blend One One
CGPROGRAM
#pragma surface surf BlinnPhong noambient
sampler2D _ MainTex;
sampler2D _ BumpMap;
fixed4 _ Color;
half _ Shininess;
struct Input {
float2 uv _ MainTex;
float2 uv _ BumpMap;
};
void surf (Input IN, inout SurfaceOutput o) {
fixed4 tex = tex2D( _ MainTex, IN.uv _ MainTex);
o.Albedo = tex.rgb * _ Color.rgb;
o.Gloss = tex.a;
o.Alpha = tex.a * _ Color.a;
o.Specular = _ Shininess;
o.Normal = UnpackNormal(tex2D( _ BumpMap, IN.uv _ BumpMap));
}
ENDCG
}
FallBack "Specular"
}
Now apply your new shader to your character』s material and we』re
done