D3dValidateTextureStageState

This function returns the number of passes where the hardware can perform the blending operations specified in the current state.

DWORD (APIENTRY *LPD3DHAL_VALIDATETEXTURESTAGESTATECB)(
  LPD3DHAL_VALIDATETEXTURESTAGESTATEDATA pvtssd
);

Parameters

• pvtssd
  [in] Points to a D3DHAL_VALIDATETEXTURESTAGESTATEDATA structure that contains the information required for the driver to determine and return the number of passes required to perform the blending operations.

Return Values

This function returns one of the following callback codes:

• DDHAL_DRIVER_HANDLED
• DDHAL_DRIVER_NOTHANDLED

Remarks

Direct3D drivers that support texturing must implement D3dValidateTextureStageState.

The driver's implementation of this function must evaluate the current texture state for all texture stages associated with the context. If the driver's hardware can perform the specified blending operations, then the driver should return the number of passes on the state data that its hardware requires. If the hardware cannot perform the specified blending operations, then the driver should return one of the error codes in the ddrval member of the following structure as shown in the following table.

Error code	Description
D3DERR_CONFLICTINGTEXTUREFILTER	The hardware cannot do both trilinear filtering and multitexturing at the same time.
D3DERR_TOOMANYOPERATIONS	The hardware cannot handle the specified number of operations.
D3DERR_UNSUPPORTEDALPHAARG	The hardware does not support a specified alpha argument.
D3DERR_UNSUPPORTEDALPHAOPERATION	The hardware does not support a specified alpha operation.
D3DERR_UNSUPPORTEDCOLORARG	The hardware does not support a specified color argument.
D3DERR_UNSUPPORTEDCOLOROPERATION	The hardware does not support a specified color operation.
D3DERR_UNSUPPORTEDFACTORVALUE	The hardware does not support a D3DTA_TFACTOR greater than 1.0.
D3DERR_WRONGTEXTUREFORMAT	The hardware does not support the current state in the selected texture format.

Direct3D calls D3dValidateTextureStageState in response to an application request through a call to IDirect3DDevice7::ValidateDevice. The number of passes returned by the driver is propagated back to the application, which can then decide whether it will proceed with rendering using the current state or if it must change the blending operations to render faster or to render at all. There are no limits to the number of passes that a driver can return.

A driver that returns more than one pass is responsible for properly executing the passes on all state and primitive data when rendering.

The following list shows requests that are likely to fail D3dValidateTextureStageState:

• Using diffuse iterated values, either as a texture stage argument or a BLENDDIFFUSE operation is rarely supported on current hardware. Many parts can introduce only iterated color data at the last texture operation stage. For more information, see Texture Stage Arguments.

• Trying to specify the texture for each stage as its arg1 in preference to arg2.

• Attempting to use diffuse or scalar values at arbitrary multitexture blending stages. For many video cards, these values can be used only at the final texture blending state; for others, only at the first stage.

• Attempting to accomplish more in the first texture than replicate alpha to color channels or invert the input. For many cards, the blending units associated with the first texture are incapable of handling operations more complex. The following code samples attempt to use only the second texture's blending unit, if possible. The first unit is presumed to be in its default state.

  dev.SetTextureStageState( n, D3DTSS_COLORARG1, D3DTA_TEXTURE );  *
  dev.SetTextureStageState( n, D3DTSS_COLOROP, D3DTOP_SELECTARG1 ); *
  

• Performing operations for the output alpha that are more intricate than, or substantially different from, the operations specified for the color channels is less likely to be supported.

• Attempting to use the D3DTA_TFACTOR and D3DTA_DIFFUSE texture stage arguments simultaneously. Some hardware does not support this use.

• Attempting to simultaneously use multiple textures and MIP mapped trilinear filtering. Many cards do not support these simultaneous operations. If trilinear filtering has been requested for a texture involved in multitexture operations and it fails validation, turn off trilinear and try again. In this case it may be best to do multipass rendering instead.

  The following table shows the syntax used in the equations describing these operations.

  Expression	Description
  TexN (N = 0, 1, 2)	Texture bound to texture stage N
  Ctex	This texture's RGB
  Atex	This texture's Alpha
  Cin	Current color value RGB (output of previous operation)
  Ain	Current color value Alpha (output of previous operation)
  Cdif	DIFFUSE color value RGB
  Adif	DIFFUSE color value Alpha
  Cfact	FACTOR, a scalar value specified at API level RGB
  Afact	FACTOR, a scalar value specified at API level Alpha

Requirements

OS Versions: Windows CE .NET 4.0 and later.
Header: Proto.h.
Link Library: Developer implemented.

See Also

DDHAL_DRIVER_HANDLED | DDHAL_DRIVER_NOTHANDLED | D3dDrawPrimitives2 | D3DHAL_VALIDATETEXTURESTAGESTATEDATA | Direct3D Driver Functions | Texture Stage Arguments

 Last updated on Tuesday, May 18, 2004

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