static int luaB_inv (lua_State *L) {
float w, x, y, z;
if (lua_gettop(L) != 1) luaL_error(L, "Invalid params, try inv(q)");
lua_checkquat(L, 1, &w, &x, &y, &z);
lua_pushquat(L,w,x,y,z);
return 1;
}
static int luaB_unpack (lua_State *L) {
if (lua_gettop(L)==1 && lua_isvector3(L,1)) {
float x, y, z; lua_checkvector3(L, 1, &x, &y, &z);
lua_pushnumber(L,x);
lua_pushnumber(L,y);
lua_pushnumber(L,z);
return 3;
} else if (lua_gettop(L)==1 && lua_isquat(L,1)) {
float w, x, y, z; lua_checkquat(L, 1, &w, &x, &y, &z);
lua_pushnumber(L,w);
lua_pushnumber(L,x);
lua_pushnumber(L,y);
lua_pushnumber(L,z);
return 4;
} else {
int i, e, n;
luaL_checktype(L, 1, LUA_TTABLE);
i = luaL_optint(L, 2, 1);
e = luaL_opt(L, luaL_checkint, 3, luaL_getn(L, 1));
if (i > e) return 0; /* empty range */
n = e - i + 1; /* number of elements */
if (n <= 0 || !lua_checkstack(L, n)) /* n <= 0 means arith. overflow */
return luaL_error(L, "too many results to unpack");
lua_rawgeti(L, 1, i); /* push arg[i] (avoiding overflow problems) */
while (i++ < e) /* push arg[i + 1...e] */
lua_rawgeti(L, 1, i);
return n;
}
}
static int math_pow (lua_State *L) {
if (lua_gettop(L) != 2) {
luaL_error(L, "Wrong number of arguments: use math.pow(number, number) or math.pow(quat, number)");
}
if (lua_type(L, 1) != LUA_TNUMBER && lua_type(L, 1) != LUA_TQUAT) {
luaL_error(L, "Invalid type for 1st parameter, use math.pow(number, number) or math.pow(quat, number)");
}
if (lua_type(L, 2) != LUA_TNUMBER) {
luaL_error(L, "math.pow second argument must be a number");
}
if (lua_type(L, 1) == LUA_TNUMBER) {
lua_pushnumber(L, pow(lua_tonumber(L, 1), lua_tonumber(L, 2)));
} else {
float w, x, y, z, l;
float index;
lua_checkquat(L, 1, &w, &x, &y, &z);
index = (float)lua_tonumber(L, 2);
l = sqrtf(x*x + y*y + z*z);
if (l==0) {
lua_pushquat(L, 1, 0, 0, 0);
} else {
float angle, sangle;
float w2, x2, y2, z2;
angle = index * acosf(w); /* without the factor of 2 */
sangle = sinf(angle);
w2 = cosf(angle);
x2 = sangle * x/l;
y2 = sangle * y/l;
z2 = sangle * z/l;
lua_pushquat(L, w2, x2, y2, z2);
}
}
return 1;
}
static int luaB_inv (lua_State *L) {
float w, x, y, z;
if (lua_gettop(L) != 1) luaL_error(L, "Invalid params, try inv(q)");
lua_checkquat(L, 1, &w, &x, &y, &z);
/* don't invert w, as that would mean inv(Q_ID) would flip the polarity of w */
lua_pushquat(L,w,-x,-y,-z);
return 1;
}
static int luaB_slerp (lua_State *L) {
float w1, x1, y1, z1;
float w2, x2, y2, z2;
float t, theta, dot;
if (lua_gettop(L) != 3) luaL_error(L, "Invalid params, try slerp(q1,q2,a)");
lua_checkquat(L, 1, &w1, &x1, &y1, &z1);
lua_checkquat(L, 2, &w2, &x2, &y2, &z2);
t = (float)lua_tonumber(L, 3);
dot = w1*w2 + x1*x2 + y1*y2 + z1*z2;
if (dot < 0) {
/* flip one of them */
w2 *= -1;
x2 *= -1;
y2 *= -1;
z2 *= -1;
/* update dot to match */
dot *= -1;
}
/* dot > 0 now */
/* Due to rounding errors, even when vectors are normalised in Lua, dot can be > 1.
* We treat this case as if dot == 1 as it can only happen when the quats are very
* similar.
*/
if (dot < 1) {
theta = acosf(dot);
float d = 1.0f / sinf(theta);
float s0 = sinf((1.0f - t) * theta);
float s1 = sinf(t * theta);
lua_pushquat(L,
d * (w1*s0 + w2*s1),
d * (x1*s0 + x2*s1),
d * (y1*s0 + y2*s1),
d * (z1*s0 + z2*s1)
);
} else {
lua_pushquat(L,w1,x1,y1,z1);
}
return 1;
}
static int luaB_norm (lua_State *L) {
if (lua_gettop(L)==1 && lua_isvector3(L,1)) {
float x, y, z;
float len;
lua_checkvector3(L, 1, &x, &y, &z);
len = sqrtf(x*x + y*y + z*z);
lua_pushvector3(L,x/len,y/len,z/len);
return 1;
} else if (lua_gettop(L)==1 && lua_isquat(L,1)) {
float w, x, y, z;
float qlen;
lua_checkquat(L, 1, &w, &x, &y, &z);
qlen = sqrtf(w*w + x*x + y*y + z*z);
lua_pushquat(L,w/qlen,x/qlen,y/qlen,z/qlen);
return 1;
} else {
luaL_error(L, "Invalid params, try norm(v) norm(q)");
return 0;
}
}
static int luaB_norm (lua_State *L) {
if (lua_gettop(L)==1 && lua_isvector2(L,1)) {
float x, y;
float len;
lua_checkvector2(L, 1, &x, &y);
len = sqrtf(x*x + y*y);
if (len == 0)
luaL_error(L, "Cannot normalise vector2(0,0)");
lua_pushvector2(L,x/len,y/len);
return 1;
} else if (lua_gettop(L)==1 && lua_isvector3(L,1)) {
float x, y, z;
float len;
lua_checkvector3(L, 1, &x, &y, &z);
len = sqrtf(x*x + y*y + z*z);
if (len == 0)
luaL_error(L, "Cannot normalise vector3(0,0,0)");
lua_pushvector3(L,x/len,y/len,z/len);
return 1;
} else if (lua_gettop(L)==1 && lua_isvector4(L,1)) {
float x, y, z, w;
float len;
lua_checkvector4(L, 1, &x, &y, &z, &w);
len = sqrtf(x*x + y*y + z*z + w*w);
if (len == 0)
luaL_error(L, "Cannot normalise vector4(0,0,0,0)");
lua_pushvector4(L,x/len,y/len,z/len,w/len);
return 1;
} else if (lua_gettop(L)==1 && lua_isquat(L,1)) {
float w, x, y, z;
float qlen;
lua_checkquat(L, 1, &w, &x, &y, &z);
qlen = sqrtf(w*w + x*x + y*y + z*z);
if (qlen == 0)
luaL_error(L, "Cannot normalise quat(0,0,0,0)");
lua_pushquat(L,w/qlen,x/qlen,y/qlen,z/qlen);
return 1;
} else {
return luaL_error(L, "Invalid arguments, try norm(v) or norm(q).");
}
}
