How to Implement the Intel® GPP Vector Module

Submit New Article

June 18, 2009 12:00 AM PDT


Challenge

Implement Intel® Graphics Performance Primitives (Intel® GPP) to provide basic vector operations. These include operations such as addition, subtraction, dot-product, cross-product, scaling, length, normalization, and transformation.

Solution

Use the functions in the Intel GPP Vector Module. These functions operate on operands represented in Qm.n and Q16.16 format. This module uses two data structures: GPP_VEC3D and GPP_VEC4D.

GPP_VEC3D, used to store the geometric position of a three-dimensional vector, is defined as follows:

typedef struct{

I32 x;

I32 y;

I32 z;

} GPP_VEC3D;

 

GPP_VEC4D

typedef struct{

I32 x;

I32 y;

I32 z;

I32 w;

} GPP_VEC4D;





gppVec3DLength _n_32s(GPP_VEC3D* v, U32* pDst, U32 n);

 

GPP_VEC3DGPP_VEC3DQm.n

v->x = 327680 ( 5.0000f)

v->y = 327680 ( 5.0000f)

v->z = 327680 ( 5.0000f)

 

Q16.16

gppVec3DLength_16_32s(v1, &len1);

*len1 = 567542

 

Qm.nQ22.10 

v->x = 5120 ( 5.0000f)

v->y = 5120 ( 5.0000f)

v->z = 5120 ( 5.0000f)



gppVec3DLength_n_32s(v1, &len2, 10);

*len2 = 8864



FEM: 5.0000f, 5.0000f, 5.0000f = 8.6602 = 8.6602

Len_16: 327680, 327680 , 327680 = 567542 = 8.6600

Len_n(n=10): 5120, 5120, 5120 = 8864 = 8.6563

 

Q22.10

GPP_MATRIX4X4

GppStatus gppVec3DTransform_16_32s 

(GPP_VEC3D* sv, GPP_VEC4D* dv, GPP_MATRIX4X4 m);

 

 

GppStatus gppVec3DTransform_n_32s 

(GPP_VEC3D* sv, GPP_VEC4D* dv GPP_MATRIX4X4 m, U32 n);

 

This item is part of a series about optimizing 3D graphics engines using Intel GPP; the series is introduced in the separate item "How to Optimize 3D Graphics on the Intel® XScale® Microarchitecture."

Source

Intel® GPP for Intel® PCA Application Processors - Vector, Matrix and Raster Modules