dusklight/libs/dolphin/pad/Padclamp.c

#include "dolphin/pad/Padclamp.h"

// older version of MSL_C sqrtf. needed here instead of updated version
static inline f32 dolsqrtf(f32 x) {
    static const f64 _half = .5;
    static const f64 _three = 3.0;
    vf32 y;
    if (x > 0.0f) {
        f64 guess = __frsqrte((f64)x);                         // returns an approximation to
        guess = _half * guess * (_three - guess * guess * x);  // now have 12 sig bits
        guess = _half * guess * (_three - guess * guess * x);  // now have 24 sig bits
        guess = _half * guess * (_three - guess * guess * x);  // now have 32 sig bits
        y = (f32)(x * guess);
        return y;
    }
    return x;
}

static void ClampStick(s8* px, s8* py, s8 max, s8 xy, s8 min);
static void ClampCircle(s8* px, s8* py, s8 radius, s8 min);

/* 8034DDBC-8034DEEC 3486FC 0130+00 1/1 0/0 0/0 .text            ClampStick */
static void ClampStick(s8* px, s8* py, s8 max, s8 xy, s8 min) {
    int x = *px;
    int y = *py;
    int signX;
    int signY;
    int d;

    if (0 <= x) {
        signX = 1;
    } else {
        signX = -1;
        x = -x;
    }

    if (0 <= y) {
        signY = 1;
    } else {
        signY = -1;
        y = -y;
    }

    if (x <= min) {
        x = 0;
    } else {
        x -= min;
    }
    if (y <= min) {
        y = 0;
    } else {
        y -= min;
    }

    if (x == 0 && y == 0) {
        *px = *py = 0;
        return;
    }

    if (xy * y <= xy * x) {
        d = xy * x + (max - xy) * y;
        if (xy * max < d) {
            x = (s8)(xy * max * x / d);
            y = (s8)(xy * max * y / d);
        }
    } else {
        d = xy * y + (max - xy) * x;
        if (xy * max < d) {
            x = (s8)(xy * max * x / d);
            y = (s8)(xy * max * y / d);
        }
    }

    *px = (s8)(signX * x);
    *py = (s8)(signY * y);
}

/* 8034DEEC-8034E094 34882C 01A8+00 1/1 0/0 0/0 .text            ClampCircle */
void ClampCircle(s8* px, s8* py, s8 radius, s8 min) {
    int x = *px;
    int y = *py;
    int squared;
    int length;

    if (-min < x && x < min) {
        x = 0;
    } else if (0 < x) {
        x -= min;
    } else {
        x += min;
    }

    if (-min < y && y < min) {
        y = 0;
    } else if (0 < y) {
        y -= min;
    } else {
        y += min;
    }

    squared = x * x + y * y;
    if (radius * radius < squared) {
        length = dolsqrtf(squared);
        x = (x * radius) / length;
        y = (y * radius) / length;
    }

    *px = x;
    *py = y;
}

/* ############################################################################################## */
/* 803A2170-803A2180 02E7D0 000A+06 2/2 0/0 0/0 .rodata          ClampRegion */
static const PADClampRegion ClampRegion = {
    // Triggers
    30,
    180,

    // Left stick
    15,
    72,
    40,

    // Right stick
    15,
    59,
    31,

    // Stick radii
    56,
    44,
};

inline void ClampTrigger(u8* trigger, u8 min, u8 max) {
    if (*trigger <= min) {
        *trigger = 0;
    } else {
        if (max < *trigger) {
            *trigger = max;
        }
        *trigger -= min;
    }
}

/* 8034E094-8034E1A8 3489D4 0114+00 0/0 1/1 0/0 .text            PADClamp */
void PADClamp(PADStatus* status) {
    int i;
    for (i = 0; i < 4; i++, status++) {
        if (status->error != PAD_ERR_NONE) {
            continue;
        }

        ClampStick(&status->stick_x, &status->stick_y, ClampRegion.maxStick, ClampRegion.xyStick,
                   ClampRegion.minStick);
        ClampStick(&status->substick_x, &status->substick_y, ClampRegion.maxSubstick,
                   ClampRegion.xySubstick, ClampRegion.minSubstick);
        ClampTrigger(&status->trigger_left, ClampRegion.minTrigger, ClampRegion.maxTrigger);
        ClampTrigger(&status->trigger_right, ClampRegion.minTrigger, ClampRegion.maxTrigger);
    }
}

/* 8034E1A8-8034E2B4 348AE8 010C+00 0/0 1/1 0/0 .text            PADClampCircle */
void PADClampCircle(PADStatus* status) {
    int i;
    for (i = 0; i < 4; ++i, status++) {
        if (status->error != PAD_ERR_NONE) {
            continue;
        }

        ClampCircle(&status->stick_x, &status->stick_y, ClampRegion.radStick, ClampRegion.minStick);
        ClampCircle(&status->substick_x, &status->substick_y, ClampRegion.radSubstick,
                    ClampRegion.minSubstick);
        ClampTrigger(&status->trigger_left, ClampRegion.minTrigger, ClampRegion.maxTrigger);
        ClampTrigger(&status->trigger_right, ClampRegion.minTrigger, ClampRegion.maxTrigger);
    }
}