sincos (Pixel Shader)

Computes sine and cosine, in radians. The x-component of result contains cos(x). The y component contains sin(x). The src1 register needs to have a replicate swizzle to indicate which channel is used.

Syntax

where

• dst is the destination register. Should be a temporary register.
• src0 is a source register that provides the input angle. The angle must be within [-Pi, +Pi].
• src1 is a source register. Must be a constant register. For ps_3_0 or above, this parameter is not strictly needed, as the component values are provided.
• src2 is a source register. Must be a constant register. For ps_3_0 or above, this parameter is not strictly needed, as the component values are provided.

Remarks

Source register rules:

• src0.w is an angle measured in radians between -Pi and +Pi.
• src1 = (-1.0f/(7!*128), -1.0f/(6!*64), 1/(4!*16), 1/(5!*32) ).
• src2 = (-1.0f/(3!*8), -1.0f/(2!*8), 1, 0.5f).

These values are defined in the following macros: D3DSINCOSCONST1 and D3DSINCOSCONST2.

Destination register rules:

• dest.x = cos(src1.selected_channel), dest.y = sin(src1.selected_channel), dest.z is undefined after the instruction.
• dest should not be the same register as src1.
• Only .x and .y are allowed to be in the destination write mask.

The maximum absolute error is 0.002.

This is a macro instruction, which takes eight instruction slots.

If application wants to compute sincos for an arbitrary angle, then the angle could be mapped to the range -Pi to +Pi by using the following macro (r0.x holds the original angle).

def c0, Pi, 0.5f, 2*Pi, 1/(2*Pi)
mad r0.x, r.x, c0.w, c0.y
frc r0.x, r0.x
mad r0.x, r0.x, c0.z, -c0.x

Instruction Information

Related Topics

• D3DSINCOSCONST1
• D3DSINCOSCONST2