matrixlookatlh.c

来自「Simple Cube plotting using frame buffers」· C语言 代码 · 共 26 行

#include <altivec.h>
#include <normalize4.h>
#include <cross_product4.h>
#include <dot_product4.h>
#include <transpose_matrix4x4.h>
#include "matrixLookAtLH.h"

inline void matrixLookAtLH(vector float *out, vector float pEye,
							vector float pAt, vector float pUp){
								
	vector float zaxis = _normalize4(vec_sub(pAt, pEye));
	vector float xaxis = _normalize4(_cross_product4(pUp, zaxis));
	vector float yaxis = _cross_product4(zaxis, xaxis);
	vector float waxis = (vector float) { 	-(_dot_product4(xaxis, pEye)),
											-(_dot_product4(yaxis, pEye)),
											-(_dot_product4(zaxis, pEye)),
											1.0f}; 
	vector float temp[4];
	temp[0] = xaxis;
	temp[1] = yaxis;
	temp[2] = zaxis;
	temp[3] = (vector float) { 0.0f, 0.0f, 0.0f, 0.0f };
	_transpose_matrix4x4(out, temp);
	out[3] = waxis;
	}