Microsoft DirectX 8.1 (pixel shader versions 1.0, 1.1, 1.2, 1.3, 1.4)

def

Provides a method to define constants to be used within the pixel shader.

def dest, fVal0, fVal1, fVal2, fVal3

Registers

Argument	Description	Registers				Version
Argument	Description	v_n	c_n	t_n	r_n	Version
dest	Destination register		x			1.0, 1.1, 1.2, 1.3, 1.4
fVal0, fVal1, fVal2, fVal3	Source floating point value	N/A	N/A	N/A	N/A	1.0, 1.1, 1.2, 1.3, 1.4

N/A Not applicable. The float values do not use registers.

Each of the float values in fVal0, fVal1, fVal2, fVal3 is between -1.0 and 1.0. This is not necessarily the number specified in MAXPIXELSHADERVALUE.

To learn more about registers, see Registers.

Remarks

def instructions must be placed after the version instruction and before any arithmetic or texture address instructions.

The def instruction is an alternative to setting pixel shader constants by calling SetPixelShaderConstant. When SetPixelShader is called, the def instruction is effectively translated into a SetPixelShaderConstant call. Constant registers that are initialized by the def instruction during SetPixelShader, may be overwritten by calling SetPixelShaderConstant manually.

This instruction does not count against the instruction limit. It is stripped from the instruction stream prior to being sent to the driver.

For more information about MAXPIXELSHADERVALUE, see D3DCAPS8.

Example

// This example outputs a constant color.

// The shader is shown below.
ps.1.0                              // version instruction
def c0, 1.0f, 0.0f, 0.0f, 1.0f      // set c0 register
mov r0, c0                          // output constant color