shithub: tinygl

ref: 1c72eafd3c9621e41723ae6d379dfbb9cebd18ac
dir: /src/zmath.h/

#ifndef __ZMATH__
#define __ZMATH__
#include "../include/GL/gl.h"
#include <stdlib.h>
#include <string.h> //For memcpy
#include <math.h>
/* Matrix & Vertex */

typedef struct {
	GLfloat m[4][4];
} M4;

typedef struct {
	GLfloat m[3][3];
} M3;

typedef struct {
	GLfloat m[3][4];
} M34;

#define X v[0]
#define Y v[1]
#define Z v[2]
#define W v[3]

typedef struct {
	GLfloat v[3];
} V3;

typedef struct {
	GLfloat v[4];
} V4;

void gl_M4_Id(M4* a);
int gl_M4_IsId(M4* a);
void gl_M4_Move(M4* a, M4* b);
void gl_MoveV3(V3* a, V3* b);
void gl_MulM4V3(V3* a, M4* b, V3* c);
void gl_MulM3V3(V3* a, M4* b, V3* c);

void gl_M4_MulV4(V4* a, M4* b, V4* c);
void gl_M4_InvOrtho(M4* a, M4 b);
void gl_M4_Inv(M4* a, M4* b);
void gl_M4_Mul(M4* c, M4* a, M4* b);
void gl_M4_MulLeft(M4* c, M4* a);
void gl_M4_Transpose(M4* a, M4* b);
void gl_M4_Rotate(M4* c, GLfloat t, GLint u);
//int gl_V3_Norm(V3* a);
//int gl_V3_Norm_Fast(V3* a);



V3 gl_V3_New(GLfloat x, GLfloat y, GLfloat z);
V4 gl_V4_New(GLfloat x, GLfloat y, GLfloat z, GLfloat w);

int gl_Matrix_Inv(GLfloat* r, GLfloat* m, GLint n);

/*
static inline GLfloat fastInvSqrt(float x){
	GLint i; GLfloat y;
	memcpy(&i, &x, 4);
	i = 0x5f3759df - (i>>1);
	//y = (union{GLint l; GLfloat f; }){i}.f;
	memcpy(&y, &i, 4);
	return y * (1.5F - 0.5F * x * y * y);
}
*/
#if TGL_FEATURE_FISR == 1
inline GLfloat fastInvSqrt(float x){
	union{GLfloat f; GLint i;} conv;
	conv.f = x;
	conv.i = 0x5F1FFFF9 - (conv.i>>1);
	conv.f *= 0.703952253f * (2.38924456f - x * conv.f * conv.f);
	return conv.f;
}
#endif


inline int gl_V3_Norm_Fast(V3* a) {
	GLfloat n;
#if TGL_FEATURE_FISR == 1
	n = fastInvSqrt(a->X * a->X + a->Y * a->Y + a->Z * a->Z); //FISR
	if(n>1E+3)
		return 1;
#else
	n = sqrt(a->X * a->X + a->Y * a->Y + a->Z * a->Z); //NONFISR
	if (n == 0)
		return 1;
	n = 1.0 / n;
#endif
	a->X *= n;
	a->Y *= n;
	a->Z *= n;
	return 0;
}
#endif
// __ZMATH__