AffineTransform

Syntax

Parameters

pSrc1

Pointer to the source 4x4 matrix src1.

pSrc2

Pointer to the source vector src2 or array of vectors.

src2Stride0

Stride between the vectors in the source array.

pDst

Pointer to the destination vector dst or array of vectors.

dstStride0

Stride between the vectors in the destination array.

count

The number of vectors in the arrays.

Description

The functions ippmAffineTransform_m4v2_32f, ippmAffineTransform_m4v3_32f, ippmAffineTransform_m4v4_32f, ippmAffineTransform_m4v2a_32f, ippmAffineTransform_m4v3a_32f, and ippmAffineTransform_m4v4a_32f are declared in the ippm.h file. These functions perform an affine transformation of a vector or array of vectors in a Homogeneous coordinate space. The transformation is determined by the src1 matrix. The functions whose names contain the v2, v3, or v4 characters in the descriptor, operate on 2D, 3D, or 4D vectors, respectively. The functions whose names contain the a character before the underscore transform vector arrays, whereas the other functions transform vectors.

Provided that the 4x4 matrix src1 is represented as a 16-element array, the transformation uses the following formulae, depending on the dimension of the vectors:

• For 2D vectors,

  dst[0] = src1[0] * src2[0] + src1[4] * src2[1] + src1[12]

  dst[1] = src1[1] * src2[0] + src1[5] * src2[1] + src1[13]

  dst[2] = src1[2] * src2[0] + src1[6] * src2[1] + src1[14]

  dst[3] = src1[3] * src2[0] + src1[7] * src2[1] + src1[15]

• For 3D vectors,

  dst[0] = src1[0] * src2[0] + src1[4] * src2[1] + src1[ 8] * src2[2] + src1[12]

  dst[1] = src1[1] * src2[0] + src1[5] * src2[1] + src1[ 9] * src2[2] + src1[13]

  dst[2] = src1[2] * src2[0] + src1[6] * src2[1] + src1[10] * src2[2] + src1[14]

  dst[3] = src1[3] * src2[0] + src1[7] * src2[1] + src1[11] * src2[2] + src1[15]

• For 4D vectors,

  dst[0] = src1[0] * src2[0] + src1[4] * src2[1] + src1[ 8] * src2[2] + src1[12] * pSrc2[3]

  dst[1] = src1[1] * src2[0] + src1[5] * src2[1] + src1[ 9] * src2[2] + src1[13] * pSrc2[3]

  dst[2] = src1[2] * src2[0] + src1[6] * src2[1] + src1[10] * src2[2] + src1[14] * pSrc2[3]

  dst[3] = src1[3] * src2[0] + src1[7] * src2[1] + src1[11] * src2[2] + src1[15] * pSrc2[3]

Return Values