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							571 lines
						
					
					
						
							12 KiB
						
					
					
				#ifndef LINMATH_H | 
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#define LINMATH_H | 
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 | 
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#include <math.h> | 
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 | 
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#ifdef _MSC_VER  | 
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#define inline __inline | 
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#endif | 
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 | 
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#define LINMATH_H_DEFINE_VEC(n) \ | 
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typedef float vec##n[n]; \ | 
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static inline void vec##n##_add(vec##n r, vec##n const a, vec##n const b) \ | 
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{ \ | 
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	int i; \ | 
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	for(i=0; i<n; ++i) \ | 
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		r[i] = a[i] + b[i]; \ | 
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} \ | 
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static inline void vec##n##_sub(vec##n r, vec##n const a, vec##n const b) \ | 
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{ \ | 
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	int i; \ | 
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	for(i=0; i<n; ++i) \ | 
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		r[i] = a[i] - b[i]; \ | 
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} \ | 
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static inline void vec##n##_scale(vec##n r, vec##n const v, float const s) \ | 
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{ \ | 
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	int i; \ | 
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	for(i=0; i<n; ++i) \ | 
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		r[i] = v[i] * s; \ | 
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} \ | 
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static inline float vec##n##_mul_inner(vec##n const a, vec##n const b) \ | 
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{ \ | 
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	float p = 0.; \ | 
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	int i; \ | 
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	for(i=0; i<n; ++i) \ | 
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		p += b[i]*a[i]; \ | 
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	return p; \ | 
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} \ | 
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static inline float vec##n##_len(vec##n const v) \ | 
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{ \ | 
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	return (float) sqrt(vec##n##_mul_inner(v,v)); \ | 
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} \ | 
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static inline void vec##n##_norm(vec##n r, vec##n const v) \ | 
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{ \ | 
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	float k = 1.f / vec##n##_len(v); \ | 
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	vec##n##_scale(r, v, k); \ | 
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} | 
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 | 
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LINMATH_H_DEFINE_VEC(2) | 
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LINMATH_H_DEFINE_VEC(3) | 
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LINMATH_H_DEFINE_VEC(4) | 
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 | 
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static inline void vec3_mul_cross(vec3 r, vec3 const a, vec3 const b) | 
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{ | 
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	r[0] = a[1]*b[2] - a[2]*b[1]; | 
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	r[1] = a[2]*b[0] - a[0]*b[2]; | 
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	r[2] = a[0]*b[1] - a[1]*b[0]; | 
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} | 
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 | 
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static inline void vec3_reflect(vec3 r, vec3 const v, vec3 const n) | 
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{ | 
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	float p  = 2.f*vec3_mul_inner(v, n); | 
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	int i; | 
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	for(i=0;i<3;++i) | 
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		r[i] = v[i] - p*n[i]; | 
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} | 
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 | 
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static inline void vec4_mul_cross(vec4 r, vec4 a, vec4 b) | 
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{ | 
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	r[0] = a[1]*b[2] - a[2]*b[1]; | 
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	r[1] = a[2]*b[0] - a[0]*b[2]; | 
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	r[2] = a[0]*b[1] - a[1]*b[0]; | 
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	r[3] = 1.f; | 
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} | 
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 | 
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static inline void vec4_reflect(vec4 r, vec4 v, vec4 n) | 
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{ | 
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	float p  = 2.f*vec4_mul_inner(v, n); | 
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	int i; | 
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	for(i=0;i<4;++i) | 
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		r[i] = v[i] - p*n[i]; | 
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} | 
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 | 
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typedef vec4 mat4x4[4]; | 
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static inline void mat4x4_identity(mat4x4 M) | 
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{ | 
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	int i, j; | 
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	for(i=0; i<4; ++i) | 
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		for(j=0; j<4; ++j) | 
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			M[i][j] = i==j ? 1.f : 0.f; | 
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} | 
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static inline void mat4x4_dup(mat4x4 M, mat4x4 N) | 
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{ | 
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	int i, j; | 
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	for(i=0; i<4; ++i) | 
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		for(j=0; j<4; ++j) | 
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			M[i][j] = N[i][j]; | 
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} | 
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static inline void mat4x4_row(vec4 r, mat4x4 M, int i) | 
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{ | 
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	int k; | 
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	for(k=0; k<4; ++k) | 
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		r[k] = M[k][i]; | 
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} | 
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static inline void mat4x4_col(vec4 r, mat4x4 M, int i) | 
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{ | 
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	int k; | 
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	for(k=0; k<4; ++k) | 
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		r[k] = M[i][k]; | 
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} | 
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static inline void mat4x4_transpose(mat4x4 M, mat4x4 N) | 
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{ | 
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	int i, j; | 
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	for(j=0; j<4; ++j) | 
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		for(i=0; i<4; ++i) | 
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			M[i][j] = N[j][i]; | 
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} | 
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static inline void mat4x4_add(mat4x4 M, mat4x4 a, mat4x4 b) | 
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{ | 
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	int i; | 
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	for(i=0; i<4; ++i) | 
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		vec4_add(M[i], a[i], b[i]); | 
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} | 
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static inline void mat4x4_sub(mat4x4 M, mat4x4 a, mat4x4 b) | 
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{ | 
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	int i; | 
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	for(i=0; i<4; ++i) | 
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		vec4_sub(M[i], a[i], b[i]); | 
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} | 
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static inline void mat4x4_scale(mat4x4 M, mat4x4 a, float k) | 
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{ | 
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	int i; | 
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	for(i=0; i<4; ++i) | 
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		vec4_scale(M[i], a[i], k); | 
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} | 
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static inline void mat4x4_scale_aniso(mat4x4 M, mat4x4 a, float x, float y, float z) | 
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{ | 
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	int i; | 
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	vec4_scale(M[0], a[0], x); | 
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	vec4_scale(M[1], a[1], y); | 
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	vec4_scale(M[2], a[2], z); | 
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	for(i = 0; i < 4; ++i) { | 
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		M[3][i] = a[3][i]; | 
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	} | 
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} | 
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static inline void mat4x4_mul(mat4x4 M, mat4x4 a, mat4x4 b) | 
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{ | 
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	mat4x4 temp; | 
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	int k, r, c; | 
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	for(c=0; c<4; ++c) for(r=0; r<4; ++r) { | 
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		temp[c][r] = 0.f; | 
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		for(k=0; k<4; ++k) | 
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			temp[c][r] += a[k][r] * b[c][k]; | 
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	} | 
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	mat4x4_dup(M, temp); | 
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} | 
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static inline void mat4x4_mul_vec4(vec4 r, mat4x4 M, vec4 v) | 
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{ | 
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	int i, j; | 
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	for(j=0; j<4; ++j) { | 
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		r[j] = 0.f; | 
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		for(i=0; i<4; ++i) | 
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			r[j] += M[i][j] * v[i]; | 
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	} | 
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} | 
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static inline void mat4x4_translate(mat4x4 T, float x, float y, float z) | 
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{ | 
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	mat4x4_identity(T); | 
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	T[3][0] = x; | 
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	T[3][1] = y; | 
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	T[3][2] = z; | 
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} | 
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static inline void mat4x4_translate_in_place(mat4x4 M, float x, float y, float z) | 
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{ | 
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	vec4 t = {x, y, z, 0}; | 
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	vec4 r; | 
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	int i; | 
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	for (i = 0; i < 4; ++i) { | 
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		mat4x4_row(r, M, i); | 
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		M[3][i] += vec4_mul_inner(r, t); | 
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	} | 
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} | 
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static inline void mat4x4_from_vec3_mul_outer(mat4x4 M, vec3 a, vec3 b) | 
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{ | 
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	int i, j; | 
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	for(i=0; i<4; ++i) for(j=0; j<4; ++j) | 
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		M[i][j] = i<3 && j<3 ? a[i] * b[j] : 0.f; | 
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} | 
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static inline void mat4x4_rotate(mat4x4 R, mat4x4 M, float x, float y, float z, float angle) | 
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{ | 
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	float s = sinf(angle); | 
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	float c = cosf(angle); | 
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	vec3 u = {x, y, z}; | 
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 | 
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	if(vec3_len(u) > 1e-4) { | 
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		vec3_norm(u, u); | 
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		mat4x4 T; | 
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		mat4x4_from_vec3_mul_outer(T, u, u); | 
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 | 
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		mat4x4 S = { | 
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			{    0,  u[2], -u[1], 0}, | 
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			{-u[2],     0,  u[0], 0}, | 
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			{ u[1], -u[0],     0, 0}, | 
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			{    0,     0,     0, 0} | 
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		}; | 
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		mat4x4_scale(S, S, s); | 
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 | 
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		mat4x4 C; | 
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		mat4x4_identity(C); | 
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		mat4x4_sub(C, C, T); | 
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 | 
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		mat4x4_scale(C, C, c); | 
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 | 
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		mat4x4_add(T, T, C); | 
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		mat4x4_add(T, T, S); | 
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 | 
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		T[3][3] = 1.;		 | 
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		mat4x4_mul(R, M, T); | 
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	} else { | 
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		mat4x4_dup(R, M); | 
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	} | 
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} | 
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static inline void mat4x4_rotate_X(mat4x4 Q, mat4x4 M, float angle) | 
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{ | 
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	float s = sinf(angle); | 
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	float c = cosf(angle); | 
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	mat4x4 R = { | 
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		{1.f, 0.f, 0.f, 0.f}, | 
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		{0.f,   c,   s, 0.f}, | 
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		{0.f,  -s,   c, 0.f}, | 
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		{0.f, 0.f, 0.f, 1.f} | 
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	}; | 
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	mat4x4_mul(Q, M, R); | 
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} | 
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static inline void mat4x4_rotate_Y(mat4x4 Q, mat4x4 M, float angle) | 
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{ | 
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	float s = sinf(angle); | 
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	float c = cosf(angle); | 
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	mat4x4 R = { | 
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		{   c, 0.f,   s, 0.f}, | 
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		{ 0.f, 1.f, 0.f, 0.f}, | 
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		{  -s, 0.f,   c, 0.f}, | 
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		{ 0.f, 0.f, 0.f, 1.f} | 
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	}; | 
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	mat4x4_mul(Q, M, R); | 
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} | 
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static inline void mat4x4_rotate_Z(mat4x4 Q, mat4x4 M, float angle) | 
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{ | 
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	float s = sinf(angle); | 
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	float c = cosf(angle); | 
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	mat4x4 R = { | 
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		{   c,   s, 0.f, 0.f}, | 
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		{  -s,   c, 0.f, 0.f}, | 
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		{ 0.f, 0.f, 1.f, 0.f}, | 
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		{ 0.f, 0.f, 0.f, 1.f} | 
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	}; | 
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	mat4x4_mul(Q, M, R); | 
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} | 
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static inline void mat4x4_invert(mat4x4 T, mat4x4 M) | 
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{ | 
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	float s[6]; | 
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	float c[6]; | 
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	s[0] = M[0][0]*M[1][1] - M[1][0]*M[0][1]; | 
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	s[1] = M[0][0]*M[1][2] - M[1][0]*M[0][2]; | 
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	s[2] = M[0][0]*M[1][3] - M[1][0]*M[0][3]; | 
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	s[3] = M[0][1]*M[1][2] - M[1][1]*M[0][2]; | 
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	s[4] = M[0][1]*M[1][3] - M[1][1]*M[0][3]; | 
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	s[5] = M[0][2]*M[1][3] - M[1][2]*M[0][3]; | 
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 | 
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	c[0] = M[2][0]*M[3][1] - M[3][0]*M[2][1]; | 
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	c[1] = M[2][0]*M[3][2] - M[3][0]*M[2][2]; | 
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	c[2] = M[2][0]*M[3][3] - M[3][0]*M[2][3]; | 
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	c[3] = M[2][1]*M[3][2] - M[3][1]*M[2][2]; | 
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	c[4] = M[2][1]*M[3][3] - M[3][1]*M[2][3]; | 
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	c[5] = M[2][2]*M[3][3] - M[3][2]*M[2][3]; | 
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	 | 
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	/* Assumes it is invertible */ | 
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	float idet = 1.0f/( s[0]*c[5]-s[1]*c[4]+s[2]*c[3]+s[3]*c[2]-s[4]*c[1]+s[5]*c[0] ); | 
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	 | 
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	T[0][0] = ( M[1][1] * c[5] - M[1][2] * c[4] + M[1][3] * c[3]) * idet; | 
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	T[0][1] = (-M[0][1] * c[5] + M[0][2] * c[4] - M[0][3] * c[3]) * idet; | 
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	T[0][2] = ( M[3][1] * s[5] - M[3][2] * s[4] + M[3][3] * s[3]) * idet; | 
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	T[0][3] = (-M[2][1] * s[5] + M[2][2] * s[4] - M[2][3] * s[3]) * idet; | 
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 | 
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	T[1][0] = (-M[1][0] * c[5] + M[1][2] * c[2] - M[1][3] * c[1]) * idet; | 
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	T[1][1] = ( M[0][0] * c[5] - M[0][2] * c[2] + M[0][3] * c[1]) * idet; | 
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	T[1][2] = (-M[3][0] * s[5] + M[3][2] * s[2] - M[3][3] * s[1]) * idet; | 
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	T[1][3] = ( M[2][0] * s[5] - M[2][2] * s[2] + M[2][3] * s[1]) * idet; | 
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 | 
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	T[2][0] = ( M[1][0] * c[4] - M[1][1] * c[2] + M[1][3] * c[0]) * idet; | 
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	T[2][1] = (-M[0][0] * c[4] + M[0][1] * c[2] - M[0][3] * c[0]) * idet; | 
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	T[2][2] = ( M[3][0] * s[4] - M[3][1] * s[2] + M[3][3] * s[0]) * idet; | 
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	T[2][3] = (-M[2][0] * s[4] + M[2][1] * s[2] - M[2][3] * s[0]) * idet; | 
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 | 
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	T[3][0] = (-M[1][0] * c[3] + M[1][1] * c[1] - M[1][2] * c[0]) * idet; | 
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	T[3][1] = ( M[0][0] * c[3] - M[0][1] * c[1] + M[0][2] * c[0]) * idet; | 
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	T[3][2] = (-M[3][0] * s[3] + M[3][1] * s[1] - M[3][2] * s[0]) * idet; | 
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	T[3][3] = ( M[2][0] * s[3] - M[2][1] * s[1] + M[2][2] * s[0]) * idet; | 
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} | 
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static inline void mat4x4_orthonormalize(mat4x4 R, mat4x4 M) | 
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{ | 
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	mat4x4_dup(R, M); | 
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	float s = 1.; | 
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	vec3 h; | 
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 | 
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	vec3_norm(R[2], R[2]); | 
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	 | 
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	s = vec3_mul_inner(R[1], R[2]); | 
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	vec3_scale(h, R[2], s); | 
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	vec3_sub(R[1], R[1], h); | 
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	vec3_norm(R[2], R[2]); | 
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 | 
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	s = vec3_mul_inner(R[1], R[2]); | 
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	vec3_scale(h, R[2], s); | 
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	vec3_sub(R[1], R[1], h); | 
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	vec3_norm(R[1], R[1]); | 
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 | 
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	s = vec3_mul_inner(R[0], R[1]); | 
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	vec3_scale(h, R[1], s); | 
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	vec3_sub(R[0], R[0], h); | 
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	vec3_norm(R[0], R[0]); | 
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} | 
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 | 
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static inline void mat4x4_frustum(mat4x4 M, float l, float r, float b, float t, float n, float f) | 
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{ | 
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	M[0][0] = 2.f*n/(r-l); | 
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	M[0][1] = M[0][2] = M[0][3] = 0.f; | 
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	 | 
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	M[1][1] = 2.f*n/(t-b); | 
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	M[1][0] = M[1][2] = M[1][3] = 0.f; | 
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 | 
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	M[2][0] = (r+l)/(r-l); | 
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	M[2][1] = (t+b)/(t-b); | 
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	M[2][2] = -(f+n)/(f-n); | 
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	M[2][3] = -1.f; | 
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	 | 
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	M[3][2] = -2.f*(f*n)/(f-n); | 
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	M[3][0] = M[3][1] = M[3][3] = 0.f; | 
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} | 
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static inline void mat4x4_ortho(mat4x4 M, float l, float r, float b, float t, float n, float f) | 
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{ | 
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	M[0][0] = 2.f/(r-l); | 
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	M[0][1] = M[0][2] = M[0][3] = 0.f; | 
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 | 
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	M[1][1] = 2.f/(t-b); | 
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	M[1][0] = M[1][2] = M[1][3] = 0.f; | 
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 | 
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	M[2][2] = -2.f/(f-n); | 
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	M[2][0] = M[2][1] = M[2][3] = 0.f; | 
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	 | 
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	M[3][0] = -(r+l)/(r-l); | 
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	M[3][1] = -(t+b)/(t-b); | 
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	M[3][2] = -(f+n)/(f-n); | 
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	M[3][3] = 1.f; | 
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} | 
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static inline void mat4x4_perspective(mat4x4 m, float y_fov, float aspect, float n, float f) | 
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{ | 
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	/* NOTE: Degrees are an unhandy unit to work with. | 
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	 * linmath.h uses radians for everything! */ | 
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	float const a = 1.f / (float) tan(y_fov / 2.f); | 
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 | 
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	m[0][0] = a / aspect; | 
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	m[0][1] = 0.f; | 
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	m[0][2] = 0.f; | 
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	m[0][3] = 0.f; | 
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 | 
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	m[1][0] = 0.f; | 
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	m[1][1] = a; | 
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	m[1][2] = 0.f; | 
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	m[1][3] = 0.f; | 
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 | 
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	m[2][0] = 0.f; | 
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	m[2][1] = 0.f; | 
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	m[2][2] = -((f + n) / (f - n)); | 
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	m[2][3] = -1.f; | 
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 | 
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	m[3][0] = 0.f; | 
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	m[3][1] = 0.f; | 
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	m[3][2] = -((2.f * f * n) / (f - n)); | 
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	m[3][3] = 0.f; | 
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} | 
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static inline void mat4x4_look_at(mat4x4 m, vec3 eye, vec3 center, vec3 up) | 
						|
{ | 
						|
	/* Adapted from Android's OpenGL Matrix.java.                        */ | 
						|
	/* See the OpenGL GLUT documentation for gluLookAt for a description */ | 
						|
	/* of the algorithm. We implement it in a straightforward way:       */ | 
						|
 | 
						|
	/* TODO: The negation of of can be spared by swapping the order of | 
						|
	 *       operands in the following cross products in the right way. */ | 
						|
	vec3 f; | 
						|
	vec3_sub(f, center, eye);	 | 
						|
	vec3_norm(f, f);	 | 
						|
	 | 
						|
	vec3 s; | 
						|
	vec3_mul_cross(s, f, up); | 
						|
	vec3_norm(s, s); | 
						|
 | 
						|
	vec3 t; | 
						|
	vec3_mul_cross(t, s, f); | 
						|
 | 
						|
	m[0][0] =  s[0]; | 
						|
	m[0][1] =  t[0]; | 
						|
	m[0][2] = -f[0]; | 
						|
	m[0][3] =   0.f; | 
						|
 | 
						|
	m[1][0] =  s[1]; | 
						|
	m[1][1] =  t[1]; | 
						|
	m[1][2] = -f[1]; | 
						|
	m[1][3] =   0.f; | 
						|
 | 
						|
	m[2][0] =  s[2]; | 
						|
	m[2][1] =  t[2]; | 
						|
	m[2][2] = -f[2]; | 
						|
	m[2][3] =   0.f; | 
						|
 | 
						|
	m[3][0] =  0.f; | 
						|
	m[3][1] =  0.f; | 
						|
	m[3][2] =  0.f; | 
						|
	m[3][3] =  1.f; | 
						|
 | 
						|
	mat4x4_translate_in_place(m, -eye[0], -eye[1], -eye[2]); | 
						|
} | 
						|
 | 
						|
typedef float quat[4]; | 
						|
static inline void quat_identity(quat q) | 
						|
{ | 
						|
	q[0] = q[1] = q[2] = 0.f; | 
						|
	q[3] = 1.f; | 
						|
} | 
						|
static inline void quat_add(quat r, quat a, quat b) | 
						|
{ | 
						|
	int i; | 
						|
	for(i=0; i<4; ++i) | 
						|
		r[i] = a[i] + b[i]; | 
						|
} | 
						|
static inline void quat_sub(quat r, quat a, quat b) | 
						|
{ | 
						|
	int i; | 
						|
	for(i=0; i<4; ++i) | 
						|
		r[i] = a[i] - b[i]; | 
						|
} | 
						|
static inline void quat_mul(quat r, quat p, quat q) | 
						|
{ | 
						|
	vec3 w; | 
						|
	vec3_mul_cross(r, p, q); | 
						|
	vec3_scale(w, p, q[3]); | 
						|
	vec3_add(r, r, w); | 
						|
	vec3_scale(w, q, p[3]); | 
						|
	vec3_add(r, r, w); | 
						|
	r[3] = p[3]*q[3] - vec3_mul_inner(p, q); | 
						|
} | 
						|
static inline void quat_scale(quat r, quat v, float s) | 
						|
{ | 
						|
	int i; | 
						|
	for(i=0; i<4; ++i) | 
						|
		r[i] = v[i] * s; | 
						|
} | 
						|
static inline float quat_inner_product(quat a, quat b) | 
						|
{ | 
						|
	float p = 0.f; | 
						|
	int i; | 
						|
	for(i=0; i<4; ++i) | 
						|
		p += b[i]*a[i]; | 
						|
	return p; | 
						|
} | 
						|
static inline void quat_conj(quat r, quat q) | 
						|
{ | 
						|
	int i; | 
						|
	for(i=0; i<3; ++i) | 
						|
		r[i] = -q[i]; | 
						|
	r[3] = q[3]; | 
						|
} | 
						|
static inline void quat_rotate(quat r, float angle, vec3 axis) { | 
						|
	vec3 v; | 
						|
	vec3_scale(v, axis, sinf(angle / 2)); | 
						|
	int i; | 
						|
	for(i=0; i<3; ++i) | 
						|
		r[i] = v[i]; | 
						|
	r[3] = cosf(angle / 2); | 
						|
} | 
						|
#define quat_norm vec4_norm | 
						|
static inline void quat_mul_vec3(vec3 r, quat q, vec3 v) | 
						|
{ | 
						|
/* | 
						|
 * Method by Fabian 'ryg' Giessen (of Farbrausch) | 
						|
t = 2 * cross(q.xyz, v) | 
						|
v' = v + q.w * t + cross(q.xyz, t) | 
						|
 */ | 
						|
	vec3 t = {q[0], q[1], q[2]}; | 
						|
	vec3 u = {q[0], q[1], q[2]}; | 
						|
 | 
						|
	vec3_mul_cross(t, t, v); | 
						|
	vec3_scale(t, t, 2); | 
						|
 | 
						|
	vec3_mul_cross(u, u, t); | 
						|
	vec3_scale(t, t, q[3]); | 
						|
 | 
						|
	vec3_add(r, v, t); | 
						|
	vec3_add(r, r, u); | 
						|
} | 
						|
static inline void mat4x4_from_quat(mat4x4 M, quat q) | 
						|
{ | 
						|
	float a = q[3]; | 
						|
	float b = q[0]; | 
						|
	float c = q[1]; | 
						|
	float d = q[2]; | 
						|
	float a2 = a*a; | 
						|
	float b2 = b*b; | 
						|
	float c2 = c*c; | 
						|
	float d2 = d*d; | 
						|
	 | 
						|
	M[0][0] = a2 + b2 - c2 - d2; | 
						|
	M[0][1] = 2.f*(b*c + a*d); | 
						|
	M[0][2] = 2.f*(b*d - a*c); | 
						|
	M[0][3] = 0.f; | 
						|
 | 
						|
	M[1][0] = 2*(b*c - a*d); | 
						|
	M[1][1] = a2 - b2 + c2 - d2; | 
						|
	M[1][2] = 2.f*(c*d + a*b); | 
						|
	M[1][3] = 0.f; | 
						|
 | 
						|
	M[2][0] = 2.f*(b*d + a*c); | 
						|
	M[2][1] = 2.f*(c*d - a*b); | 
						|
	M[2][2] = a2 - b2 - c2 + d2; | 
						|
	M[2][3] = 0.f; | 
						|
 | 
						|
	M[3][0] = M[3][1] = M[3][2] = 0.f; | 
						|
	M[3][3] = 1.f; | 
						|
} | 
						|
 | 
						|
static inline void mat4x4o_mul_quat(mat4x4 R, mat4x4 M, quat q) | 
						|
{ | 
						|
/*  XXX: The way this is written only works for othogonal matrices. */ | 
						|
/* TODO: Take care of non-orthogonal case. */ | 
						|
	quat_mul_vec3(R[0], q, M[0]); | 
						|
	quat_mul_vec3(R[1], q, M[1]); | 
						|
	quat_mul_vec3(R[2], q, M[2]); | 
						|
 | 
						|
	R[3][0] = R[3][1] = R[3][2] = 0.f; | 
						|
	R[3][3] = 1.f; | 
						|
} | 
						|
static inline void quat_from_mat4x4(quat q, mat4x4 M) | 
						|
{ | 
						|
	float r=0.f; | 
						|
	int i; | 
						|
 | 
						|
	int perm[] = { 0, 1, 2, 0, 1 }; | 
						|
	int *p = perm; | 
						|
 | 
						|
	for(i = 0; i<3; i++) { | 
						|
		float m = M[i][i]; | 
						|
		if( m < r ) | 
						|
			continue; | 
						|
		m = r; | 
						|
		p = &perm[i]; | 
						|
	} | 
						|
 | 
						|
	r = (float) sqrt(1.f + M[p[0]][p[0]] - M[p[1]][p[1]] - M[p[2]][p[2]] ); | 
						|
 | 
						|
	if(r < 1e-6) { | 
						|
		q[0] = 1.f; | 
						|
		q[1] = q[2] = q[3] = 0.f; | 
						|
		return; | 
						|
	} | 
						|
 | 
						|
	q[0] = r/2.f; | 
						|
	q[1] = (M[p[0]][p[1]] - M[p[1]][p[0]])/(2.f*r); | 
						|
	q[2] = (M[p[2]][p[0]] - M[p[0]][p[2]])/(2.f*r); | 
						|
	q[3] = (M[p[2]][p[1]] - M[p[1]][p[2]])/(2.f*r); | 
						|
} | 
						|
 | 
						|
#endif
 | 
						|
 |