unity shader 学习一

shader中注意的问题

1大小写，例如：

#pragma vertex vert

#pragma fragment frag

2、subshader 中 pass不可或缺

SV_POSITION 顶点着色器输出的定点位置，裁剪空间中的坐标

SV_Target 描述片元着色器的输出颜色，输出的值将会存储到渲染目标

#pragma 指令告诉unity我们定义的定点着色器和片元着色器的名字

_World2Object  模型空间到世界空间的逆转矩阵

_LightColor0 unity提供的内置变量来处理光源的颜色和强度信息以及光源的方向

saturatge 把参数截取到0--1范围内

a2v 在unity中 常用的语义

POSITION   float4类型

NORMAL    float3类型

TANGENT   float4类型

TEXCOORD0到TEXCOORDN float2或者float4类型

COLOR float4或者fixed4类型

v2f 在unity中常用的语义

SV_POSTION  

COLOR0  

COLOR1  

TEXCOORD0--TEXCOORD7

Name	Type	Value
UNITY_MATRIX_MVP	float4x4	Current model * view * projection matrix.模型视图投影矩阵
UNITY_MATRIX_MV	float4x4	Current model * view matrix.模型视图矩阵
UNITY_MATRIX_V	float4x4	Current view matrix.视图矩阵
UNITY_MATRIX_P	float4x4	Current projection matrix.投影矩阵
UNITY_MATRIX_VP	float4x4	Current view * projection matrix.视图投影矩阵
UNITY_MATRIX_T_MV	float4x4	Transpose of model * view matrix.
UNITY_MATRIX_IT_MV	float4x4	Inverse transpose of model * view matrix.模型视图矩阵逆转
UNITY_MATRIX_TEXTURE0 to UNITY_MATRIX_TEXTURE3	float4x4	Texture transformation matrices.
_Object2World	float4x4	Current model matrix.
_World2Object	float4x4	Inverse of current world matrix.
_WorldSpaceCameraPos	float3	World space position of the camera.
unity_Scale	float4	xyz components unused; w contains scale for uniformly scaled objects.

Name	Type	Value
_ModelLightColor	float4	Material’s Main * Light color
_SpecularLightColor	float4	Material’s Specular * Light color
_ObjectSpaceLightPos	float4	Light’s position in object space. w component is 0 for directional lights, 1 for other lights
_Light2World	float4x4	Light to World space matrix
_World2Light	float4x4	World to Light space matrix
_Object2Light	float4x4	Object to Light space matrix

Name	Type	Value
_Time	float4	Time (t/20, t, t*2, t*3), use to animate things inside the shaders.
_SinTime	float4	Sine of time: (t/8, t/4, t/2, t).
_CosTime	float4	Cosine of time: (t/8, t/4, t/2, t).
unity_DeltaTime	float4	Delta time: (dt, 1/dt, smoothDt, 1/smoothDt).
_ProjectionParams	float4	x is 1.0 (or –1.0 if currently rendering with a flipped projection matrix), y is the camera’s near plane, z is the camera’s far plane and w is 1/FarPlane.
_ScreenParams	float4	x is the current render target width in pixels, y is the current render target height in pixels, z is 1.0 + 1.0/width and w is 1.0 + 1.0/height.