您最多选择25个主题 主题必须以中文或者字母或数字开头,可以包含连字符 (-),并且长度不得超过35个字符
 
 
 
 

194 行
5.5 KiB

#ifndef UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
#define UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
float4x4 GetWorldToViewMatrix()
{
return UNITY_MATRIX_V;
}
float4x4 GetObjectToWorldMatrix()
{
return UNITY_MATRIX_M;
}
float4x4 GetWorldToObjectMatrix()
{
return UNITY_MATRIX_I_M;
}
// Transform to homogenous clip space
float4x4 GetWorldToHClipMatrix()
{
return UNITY_MATRIX_VP;
}
float GetOddNegativeScale()
{
return unity_WorldTransformParams.w;
}
float3 TransformWorldToView(float3 positionWS)
{
return mul(GetWorldToViewMatrix(), float4(positionWS, 1.0)).xyz;
}
float3 TransformObjectToWorld(float3 positionOS)
{
return mul(GetObjectToWorldMatrix(), float4(positionOS, 1.0)).xyz;
}
float3 TransformWorldToObject(float3 positionWS)
{
return mul(GetWorldToObjectMatrix(), float4(positionWS, 1.0)).xyz;
}
float3 TransformObjectToWorldDir(float3 dirOS)
{
// Normalize to support uniform scaling
return normalize(mul((float3x3)GetObjectToWorldMatrix(), dirOS));
}
float3 TransformWorldToObjectDir(float3 dirWS)
{
// Normalize to support uniform scaling
return normalize(mul((float3x3)GetWorldToObjectMatrix(), dirWS));
}
// Transforms normal from object to world space
float3 TransformObjectToWorldNormal(float3 normalOS)
{
#ifdef UNITY_ASSUME_UNIFORM_SCALING
return UnityObjectToWorldDir(normalOS);
#else
// Normal need to be multiply by inverse transpose
// mul(IT_M, norm) => mul(norm, I_M) => {dot(norm, I_M.col0), dot(norm, I_M.col1), dot(norm, I_M.col2)}
return normalize(mul(normalOS, (float3x3)GetWorldToObjectMatrix()));
#endif
}
// Tranforms position from world space to homogenous space
float4 TransformWorldToHClip(float3 positionWS)
{
return mul(GetWorldToHClipMatrix(), float4(positionWS, 1.0));
}
float3 GetAbsolutePositionWS(float3 positionWS)
{
#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
positionWS += _WorldSpaceCameraPos;
#endif
return positionWS;
}
float3 GetCameraRelativePositionWS(float3 positionWS)
{
#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
positionWS -= _WorldSpaceCameraPos;
#endif
return positionWS;
}
// Note: '_WorldSpaceCameraPos' is set by the legacy Unity code.
float3 GetPrimaryCameraPosition()
{
return GetCameraRelativePositionWS(_WorldSpaceCameraPos);
}
// Could be e.g. the position of a primary camera or a shadow-casting light.
float3 GetCurrentViewPosition()
{
#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_SHADOWS)
return GetPrimaryCameraPosition();
#else
// TEMP: this is rather expensive. Then again, we need '_WorldSpaceCameraPos'
// to represent the position of the primary (scene view) camera in order to
// have identical tessellation levels for both the scene view and shadow views.
// Otherwise, depth comparisons become meaningless!
float4x4 trViewMat = transpose(GetWorldToViewMatrix());
float3 rotCamPos = trViewMat[3].xyz;
return mul((float3x3)trViewMat, -rotCamPos);
#endif
}
// Returns the forward (central) direction of the current view in the world space.
float3 GetViewForwardDir()
{
float4x4 viewMat = GetWorldToViewMatrix();
return -viewMat[2].xyz;
}
// Returns 'true' if the current view performs a perspective projection.
bool IsPerspectiveProjection()
{
#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_SHADOWS)
return (unity_OrthoParams.w == 0);
#else
// TODO: set 'unity_OrthoParams' during the shadow pass.
return (GetWorldToHClipMatrix()[3].x != 0 ||
GetWorldToHClipMatrix()[3].y != 0 ||
GetWorldToHClipMatrix()[3].z != 0 ||
GetWorldToHClipMatrix()[3].w != 1);
#endif
}
// Computes the world space view direction (pointing towards the viewer).
float3 GetWorldSpaceNormalizeViewDir(float3 positionWS)
{
if (IsPerspectiveProjection())
{
// Perspective
float3 V = GetCurrentViewPosition() - positionWS;
return normalize(V);
}
else
{
// Orthographic
return -GetViewForwardDir();
}
}
float3x3 CreateWorldToTangent(float3 normal, float3 tangent, float flipSign)
{
// For odd-negative scale transforms we need to flip the sign
float sgn = flipSign * GetOddNegativeScale();
float3 bitangent = cross(normal, tangent) * sgn;
return float3x3(tangent, bitangent, normal);
}
float3 TransformTangentToWorld(float3 dirTS, float3x3 worldToTangent)
{
// Use transpose transformation to go from tangent to world as the matrix is orthogonal
return mul(dirTS, worldToTangent);
}
float3 TransformWorldToTangent(float3 dirWS, float3x3 worldToTangent)
{
return mul(worldToTangent, dirWS);
}
float3 TransformTangentToObject(float3 dirTS, float3x3 worldToTangent)
{
// Use transpose transformation to go from tangent to world as the matrix is orthogonal
float3 normalWS = mul(dirTS, worldToTangent);
return mul((float3x3)GetWorldToObjectMatrix(), normalWS);
}
float3 TransformObjectToTangent(float3 dirOS, float3x3 worldToTangent)
{
return mul(worldToTangent, TransformObjectToWorldDir(dirOS));
}
// UNITY_MATRIX_V defines a right-handed view space with the Z axis pointing towards the viewer.
// This function reverses the direction of the Z axis (so that it points forward),
// making the view space coordinate system left-handed.
void GetLeftHandedViewSpaceMatrices(out float4x4 viewMatrix, out float4x4 projMatrix)
{
viewMatrix = UNITY_MATRIX_V;
viewMatrix._31_32_33_34 = -viewMatrix._31_32_33_34;
projMatrix = UNITY_MATRIX_P;
projMatrix._13_23_33_43 = -projMatrix._13_23_33_43;
}
#endif // UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED