Messages

1

General / Re: joystick axis

« on: June 08, 2012, 12:05:56 pm »

Hi,
It seems that the previous code can be simpilfied, this version seems to produce the same results without needing to calculate the angle. Here we save calling atan2, cos and sin:

sfVector2f
sfJoystick_normaliseDirectionProportional(float x, float y)
{
#define VECTOR_LENGTH(x, y) \
  sqrtf(((x) * (x)) + ((y) * (y)))
    float in_len, ratio;
    sfVector2f res;
    if (x == 0.f && y == 0.f) {
        res.x = 0.f;
        res.y = 0.f;
        return res;
    }
    in_len = VECTOR_LENGTH(x, y);
    if (fabsf(x) > fabsf(y))
        ratio = fabsf(x / 100.f) / in_len;
    else
        ratio = fabsf(y / 100.f) / in_len;
    res.x = x * ratio;
    res.y = y * ratio;
    return res;
#undef VECTOR_LENGTH
}

again please comment if you can

2

General / Re: joystick axis

« on: June 08, 2012, 12:46:22 am »

Thanks!

I've written this code.
Maybe someone could comment if he/she see something that could be improved.
Otherwise it will perhaps be usefull for someone else :-)

#include <math.h>

sfVector2f sfJoystick_normaliseDirectionProportional(float x, float y)
{
#define VECTOR_LENGTH(x, y) \
  sqrtf(((x) * (x)) + ((y) * (y)))
    float angle, in_len, max_len, max_x, max_y, ratio, norm_x, norm_y;
    sfVector2f res;
    if (x == 0.f && y == 0.f) {
        res.x = 0.f;
        res.y = 0.f;
        return res;
    }
    angle = atan2f(y, x);
    in_len = VECTOR_LENGTH(x, y);
    if (fabsf(x) > fabsf(y)) {
        max_x = 100.f;
        max_y = max_x * y / x;
    } else {
        max_y = 100.f;
        max_x = max_y * x / y;
    }
    max_len = VECTOR_LENGTH(max_x, max_y);
    ratio = in_len / max_len;
    norm_x = cosf(angle);
    norm_y = sinf(angle);
    res.x = norm_x * ratio;
    res.y = norm_y * ratio;
    return res;
#undef VECTOR_LENGTH
}

3

General / Re: joystick axis

« on: June 06, 2012, 02:44:29 pm »

No, this is not what I want to get.

Maybe I was not precise enough in my question.

When I said "constant speed", I mean that speed in horizontal/vertical should be the same than in diagonal, but in a lot of games if we push the axis just a little the avatar moves more slowly. I want this behavior.

for exemple:
- if the input is (100, 0) I want to get (1.0, 0.0)
- if the input is (20, 0) I want to get (0.2, 0.0)
- if the input is (100, 100) I want to get (cos (pi/4), sin (pi/4))  => (0.7071, 0.7071)
- if the input is (20, 20) I want to get (cos (pi/4), sin (pi/4)) / 5  =>  (0.14142, 0.14142)

4

General / joystick axis

« on: June 05, 2012, 09:37:55 pm »

Hi,

When the player moves the joystick axis, we get values between [-100, 100].

Right is (100, 0) and upper right is (100, 100).

My problem is that I would like to move at constant speed in all directions.
When I use this input the length in horizontal and vertical is 100 and the length in diagonal is ((sqrt 2) * 100).

How can I convert this square area into a circle area ?