shithub: tinygl

ref: 3d80174a853f38ae9501774ae9946cd87d520c36
dir: /src/zmath.h/

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

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

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

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

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

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

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

void gl_M4_Id(M4* a);
GLint 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);



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

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


#if TGL_FEATURE_FISR == 1
static GLfloat fastInvSqrt(GLfloat x) {
	GLint i;
	GLfloat x2;
	memcpy(&i, &x, 4);
	i = 0x5F1FFFF9 - (i >> 1);
	memcpy(&x2, &i, 4);
	x2 *= 0.703952253f * (2.38924456f - x * x2 * x2);
	return x2;
}
#endif

static 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); 
	if (n > 1E+3)
		return 1;
#else
	n = sqrt(a->X * a->X + a->Y * a->Y + a->Z * a->Z); 
	if (n == 0)
		return 1;
	n = 1.0 / n;
#endif
	a->X *= n;
	a->Y *= n;
	a->Z *= n;
	return 0;
}
#endif