Example #1
0
File: gx.c Project: LWSS/gx
static bool line_line_intersection(vec2 a0, vec2 a1, vec2 b0, vec2 b1)
{
#if 1
    // Implemented based on http://stackoverflow.com/a/17198094/4354008
    vec2 v = vec2_sub(a0, a1);
    vec2 normal = vec2_new(v.y, -v.x);

    vec2 v0 = vec2_sub(b0, a0);
    vec2 v1 = vec2_sub(b1, a0);

    float proj0 = vec2_dot(v0, normal);
    float proj1 = vec2_dot(v1, normal);

    if ((proj0 == 0) || (proj1 == 0))
        return true;

    // TODO: float_sign()
    if ((proj0 > 0) && (proj1 < 0))
        return true;
    if ((proj0 < 0) && (proj1 > 0))
        return true;

    return false;
#else
    vec2 intersection = vec2_zero();

    vec2 b = vec2_sub(a1, a0);
    vec2 d = vec2_sub(b1, b0);
    float b_dot_p_perp = (b.x * d.y) - (b.y * d.x);

    if (b_dot_p_perp == 0)
        return false;

    vec2 c = vec2_sub(b0, a0);
    float t = ((c.x * d.y) - (c.y * d.x)) / b_dot_p_perp;
    if ((t < 0) || (t > 1))
        return false;

    float u = ((c.x * b.y) - (c.y * b.x)) / b_dot_p_perp;
    if ((u < 0) || (u > 1))
        return false;

    // TODO: make this an output parameter
    intersection = vec2_add(a0, vec2_mul(b, t));

    return true;
#endif
}
Example #2
0
static float get_angle(const float a0[2], const float a1[2],
                       const float b0[2], const float b1[2])
{
    float u[2], v[2], dot, det;
    vec2_sub(a1, a0, u);
    vec2_normalize(u, u);
    vec2_sub(b1, b0, v);
    vec2_normalize(v, v);
    dot = vec2_dot(u, v);
    det = vec2_cross(u, v);
    return atan2(det, dot);
}
Example #3
0
/////////////////////////////
// Input_GetDir
//
// Reports the direction of the dpad.
int Input_GetDir(vec2 dir) {
	float vlen;
	Uint8 buttons;
	int mx, my;
	float dlen;
	extern int _width, _height;

	// Get mouse state
	buttons = SDL_GetMouseState(&mx, &my);
	if (buttons) {
		// Use the mouse
		vec2_set(dir, mx - (_width / 2), my - (_height / 2.0f));
		dlen = 1.0f / sqrtf(vec2_dot(dir, dir));
		vec2_scale(dir, dir, dlen);
		return (1);
	} else {
		// Use the keyboar
		vec2_set(dir, 0.0f, 0.0f);
		if (Input_GetKey(InputKey_Up)) {
			dir[1] -= 1.0f;
		}
		if (Input_GetKey(InputKey_Down)) {
			dir[1] += 1.0f;
		}
		if (Input_GetKey(InputKey_Left)) {
			dir[0] -= 1.0f;
		}
		if (Input_GetKey(InputKey_Right)) {
			dir[0] += 1.0f;
		}
		vlen = vec2_dot(dir, dir);
		if (vlen > 0.0f) {
			vlen = sqrtf(vlen);
			vec2_scale(dir, dir, 1.0f / vlen);
			return (1);
		} else {
			return (0);
		}
	}
}
Example #4
0
static int _llfunc_vec2_dot(lua_State *L) {
	vec2 *a = (vec2*)userdata_get_or_die(L, 1);
	vec2 *b = (vec2*)userdata_get_or_die(L, 2);
	lua_pushnumber(L, vec2_dot(a, b));
	return 1;
}