16.2
编译HLSL 着色器
16.2.1
常量表
每个着色器有一个常量表,用来保存它的变量。D3DX库通过ID3DXConstantTable接口,提供给应用程序访问着色器的常量表。通过这个接口我们能够在应用程序中设置着色器源代码中的变量。
我们现在描述ID3DXConstantTable接口的方法列表的实现,全部的列表请查阅Direct3D文档。
16.2.1.1
取得常量句柄
为了在应用程序中设置着色器中的一个特定变量,需要有一种方法去引用它,我们能够在应用程序中用D3DXHANDLE引用一个在着色器中的变量,下面的方法返回一个着色器中的变量的D3DXHANDLE,使用时,需要传递一个变量的名字作为参数:
D3DXHANDLE ID3DXConstantTable::GetConstantByName(
D3DXHANDLE hConstant, // scope of constant
LPCSTR pName // name of constant
);
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Hconstant——我们要取得的父结构中变量句柄的D3DXHANDLE标识。例如,如果我们想获得一个特定数据结构中单一数据成员的句柄,我们可以传递结构实例的句柄。如果我们获得一个顶级变量的句柄,给这个参数设为NULL。
PName——我们想获得的句柄的着色器代码中的变量的名字。
Gets a constant by looking up its name.
D3DXHANDLE GetConstantByName(
D3DXHANDLE hConstant,
LPCSTR pName
);
Parameters
- hConstant
- [in] Unique identifier to the parent data
structure. If the constant is a top-level parameter (there is no parent data
structure), use NULL.
- pName
- [in] Name of the constant.
Return Values
Returns a unique identifier to the constant.
例如,如果在着色器中变量的名字为ViewProjMatrix,并且这是顶级变量,我们这么写:
//
取得着色器中ViewProjMatrix变量的句柄
D3DXHANDLE h0;
h0 =
ConstTable->GetConstantByName(0, "ViewProjMatrix");
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16.2.1.2
设置常量
一旦应用程序有了一个D3DXHANDLE,要引用着色器代码中的具体变量,我们可以在应用程序中使用ID3DXConstantTable::SetXXX方法设置变量。如果我们想设置一个向量数组类型的变量,方法名是SetVectorArray。
ID3DXConstantTable::SetXXX的一般语法是:
HRESULT ID3DXConstantTable::SetXXX(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
XXX value
);
|
PDevice:常量表所关联的设备的指针。
HConstant:我们正在设置的变量句柄的引用。
Value:我们要把变量设置成的值,XXX是我们设置的要替换的变量类型名,对于有些类型(bool,
int, float),传递变量值的COPY,另外一些类型(vectors,
matrices, structures),传递值的指针。
下面的列表描述了我们能用ID3DXConstantTable接口设置的类型列表。这里假定我们有一个有效的设备,和一个有效句柄。
SetBool—Used
to set a Boolean value. Sample call:
bool b = true;
ConstTable->SetBool(Device, handle, b);
|
Sets a Boolean value.
HRESULT SetBool(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
BOOL b
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the constant. See
D3DXHANDLE.
- b
- [in] Boolean value.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetBoolArray—Used
to set a Boolean array. Sample call:
bool b[3] = {true, false, true};
ConstTable->SetBoolArray(Device, handle, b, 3);
|
Sets an array of Boolean values.
HRESULT SetBoolArray(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
CONST BOOL* pB,
UINT Count
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the array of constants.
See D3DXHANDLE.
- pB
- [in] Array of Boolean values.
- Count
- [in] Number of Boolean values in the array.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetFloat—Used
to set a float. Sample call:
float f = 3.14f;
ConstTable->SetFloat(Device, handle, f);
|
Sets a floating-point number.
HRESULT SetFloat(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
FLOAT f
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the constant. See
D3DXHANDLE.
- f
- [in] Floating-point number.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetFloatArray—Used
to set a float array. Sample call:
float
f[2] = {1.0f, 2.0f};
ConstTable->SetFloatArray(Device, handle, f, 2);
|
Sets an array of floating-point numbers.
HRESULT SetFloatArray(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
CONST FLOAT* pf,
UINT Count
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the array of constants.
See D3DXHANDLE.
- pf
- [in] Array of floating-point numbers.
- Count
- [in] Number of floating-point values in the array.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetInt—Used
to set an integer. Sample call:
int x
= 4;
ConstTable->SetInt(Device, handle, x);
|
Sets an integer value.
HRESULT SetInt(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
INT n
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the constant. See
D3DXHANDLE.
- n
- [in] Integer.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetMatrix—Used
to set a 4 × 4 matrix. Sample call:
D3DXMATRIX M(…);
ConstTable->SetMatrix(Device, handle, &M);
|
Sets a nontransposed matrix.
HRESULT SetMatrix(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
CONST D3DXMATRIX* pMatrix
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the matrix of constants.
See D3DXHANDLE.
- pMatrix
- [in] Pointer to a nontransposed matrix. See
D3DXMATRIX.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetMatrixArray—Used
to set a 4 × 4 matrix array. Sample call:
D3DXMATRIX M[4];
//
...Initialize matrices
ConstTable->SetMatrixArray(Device, handle, M, 4);
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Sets an array of nontransposed matrices.
HRESULT SetMatrixArray(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
CONST D3DXMATRIX* pMatrix,
UINT Count
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to the array of constant
matrices.
- pMatrix
- [in] Array of nontransposed matrices.
- Count
- [in] Number of matrices in the array.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
SetMatrixPointerArray—Used to set an array of 4 × 4 matrix pointers. Sample call:
D3DXMATRIX* M[4];
//
...Allocate and initialize matrix pointers
ConstTable->SetMatrixPointerArray(Device, handle, M, 4);
|
Sets an array of pointers to nontransposed matrices.
HRESULT SetMatrixPointerArray(
LPDIRECT3DDEVICE9 pDevice,
D3DXHANDLE hConstant,
CONST D3DXMATRIX ** ppMatrix,
UINT Count
);
Parameters
- pDevice
- [in] Pointer to an IDirect3DDevice9 interface,
representing the device associated with the constant table.
- hConstant
- [in] Unique identifier to an array of constant
matrices.
- ppMatrix
- [in] Array of pointers to nontransposed matrices.
- Count
- [in] Number of matrices in the array.
Return Values
If the method succeeds, the return value is D3D_OK. If
the method fails, the return value can be D3DERR_INVALIDCALL.
Remarks
A nontransposed matrix contains row-major data; that
is, each vector is contained in a row.