sub

Performs subtraction. Subtracts the second source register from the first source register.

sub dest, src0, src1

Registers

To learn more about registers, see Registers.

Remarks

This instruction performs the subtraction based on the following formula.

dest = src0 - src1

Example

// This example subtracts texture color from the diffuse color.

// The shader is shown below.
ps.1.0              // Version instruction
tex t0              // Declare texture.
sub r0, v0, t0      // Subtract texture color from diffuse color.

// The following images show the contents of the source registers and 
// the resulting destination register. The colors in the second image (src1) 
// are subtracted from the color in the first image (src0) to make the 
// resulting image (dest).

// Additional code loads the texture in texture stage 0.
LPDIRECT3DDEVICE8   m_pd3dDevice;   // Init this device pointer in the application.
LPDIRECT3DTEXTURE8  m_pTexture0;    // Use this variable to hold a pointer to the texture.
TCHAR  			strPath[512] = "textureFile.jpg";

D3DUtil_CreateTexture( m_pd3dDevice, strPath, &m;_pTexture0, D3DFMT_R5G6B5 );
m_pd3dDevice->SetTexture( 0, m_pTexture0 );