spine-runtimes/spine-c/src/spine/IkConstraint.c
2016-02-27 02:13:05 +01:00

208 lines
7.0 KiB
C

/******************************************************************************
* Spine Runtimes Software License
* Version 2.3
*
* Copyright (c) 2013-2015, Esoteric Software
* All rights reserved.
*
* You are granted a perpetual, non-exclusive, non-sublicensable and
* non-transferable license to use, install, execute and perform the Spine
* Runtimes Software (the "Software") and derivative works solely for personal
* or internal use. Without the written permission of Esoteric Software (see
* Section 2 of the Spine Software License Agreement), you may not (a) modify,
* translate, adapt or otherwise create derivative works, improvements of the
* Software or develop new applications using the Software or (b) remove,
* delete, alter or obscure any trademarks or any copyright, trademark, patent
* or other intellectual property or proprietary rights notices on or in the
* Software, including any copy thereof. Redistributions in binary or source
* form must include this license and terms.
*
* THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL ESOTERIC SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/
#include <spine/IkConstraint.h>
#include <spine/Skeleton.h>
#include <spine/extension.h>
#include <float.h>
spIkConstraint* spIkConstraint_create (spIkConstraintData* data, const spSkeleton* skeleton) {
int i;
spIkConstraint* self = NEW(spIkConstraint);
CONST_CAST(spIkConstraintData*, self->data) = data;
self->bendDirection = data->bendDirection;
self->mix = data->mix;
self->bonesCount = self->data->bonesCount;
self->bones = MALLOC(spBone*, self->bonesCount);
for (i = 0; i < self->bonesCount; ++i)
self->bones[i] = spSkeleton_findBone(skeleton, self->data->bones[i]->name);
self->target = spSkeleton_findBone(skeleton, self->data->target->name);
return self;
}
void spIkConstraint_dispose (spIkConstraint* self) {
FREE(self->bones);
FREE(self);
}
void spIkConstraint_apply (spIkConstraint* self) {
switch (self->bonesCount) {
case 1:
spIkConstraint_apply1(self->bones[0], self->target->worldX, self->target->worldY, self->mix);
break;
case 2:
spIkConstraint_apply2(self->bones[0], self->bones[1], self->target->worldX, self->target->worldY, self->bendDirection,
self->mix);
break;
}
}
void spIkConstraint_apply1 (spBone* bone, float targetX, float targetY, float alpha) {
float parentRotation = !bone->parent ? 0 : spBone_getWorldRotationX(bone->parent);
float rotation = bone->rotation;
float rotationIK = ATAN2(targetY - bone->worldY, targetX - bone->worldX) * RAD_DEG - parentRotation;
if ((bone->worldSignX != bone->worldSignY) != (bone->skeleton->flipX != (bone->skeleton->flipY != spBone_isYDown())))
rotationIK = 360 - rotationIK;
if (rotationIK > 180) rotationIK -= 360;
else if (rotationIK < -180) rotationIK += 360;
spBone_updateWorldTransformWith(bone, bone->x, bone->y, rotation + (rotationIK - rotation) * alpha, bone->scaleX, bone->scaleY);
}
void spIkConstraint_apply2 (spBone* parent, spBone* child, float targetX, float targetY, int bendDir, float alpha) {
float px = parent->x, py = parent->y, psx = parent->scaleX, psy = parent->scaleY, csx = child->scaleX, cy = child->y;
int offset1, offset2, sign2;
spBone* pp = parent->parent;
float tx, ty, dx, dy, l1, l2, a1, a2, psd, r;
if (alpha == 0) return;
if (psx < 0) {
psx = -psx;
offset1 = 180;
sign2 = -1;
} else {
offset1 = 0;
sign2 = 1;
}
if (psy < 0) {
psy = -psy;
sign2 = -sign2;
}
if (csx < 0) {
csx = -csx;
offset2 = 180;
} else
offset2 = 0;
if (!pp) {
tx = targetX - px;
ty = targetY - py;
dx = child->worldX - px;
dy = child->worldY - py;
} else {
float a = pp->a, b = pp->b, c = pp->c, d = pp->d, invDet = 1 / (a * d - b * c);
float wx = pp->worldX, wy = pp->worldY, x = targetX - wx, y = targetY - wy;
tx = (x * d - y * b) * invDet - px;
ty = (y * a - x * c) * invDet - py;
x = child->worldX - wx;
y = child->worldY - wy;
dx = (x * d - y * b) * invDet - px;
dy = (y * a - x * c) * invDet - py;
}
l1 = SQRT(dx * dx + dy * dy);
l2 = child->data->length * csx;
psd = psx - psy;
if (psd < 0 ? -psd : psd <= 0.0001f) {
float cos, a, o;
l2 *= psx;
cos = (tx * tx + ty * ty - l1 * l1 - l2 * l2) / (2 * l1 * l2);
if (cos < -1) cos = -1;
else if (cos > 1) cos = 1;
a2 = ACOS(cos) * bendDir;
a = l1 + l2 * cos;
o = l2 * SIN(a2);
a1 = ATAN2(ty * a - tx * o, tx * a + ty * o);
} else {
float a = psx * l2, b = psy * l2, ta = ATAN2(ty, tx);
float aa = a * a, bb = b * b, ll = l1 * l1, dd = tx * tx + ty * ty;
float c0 = bb * ll + aa * dd - aa * bb, c1 = -2 * bb * l1, c2 = bb - aa;
float d = c1 * c1 - 4 * c2 * c0;
float minAngle = 0, minDist = FLT_MAX, minX = 0, minY = 0;
float maxAngle = 0, maxDist = 0, maxX = 0, maxY = 0;
float x = l1 + a, dist = x * x, angle, y;
cy = 0;
if (d >= 0) {
float q = SQRT(d), r0, r1, ar0, ar1;;
if (c1 < 0) q = -q;
q = -(c1 + q) / 2;
r0 = q / c2;
r1 = c0 / q;
ar0 = r0 < 0 ? -r0 : r0;
ar1 = r1 < 0 ? -r1 : r1;
r = ar0 < ar1 ? r0 : r1;
if (r * r <= dd) {
float y1 = SQRT(dd - r * r) * bendDir;
a1 = ta - ATAN2(y1, r);
a2 = ATAN2(y1 / psy, (r - l1) / psx);
goto outer;
}
}
if (dist > maxDist) {
maxAngle = 0;
maxDist = dist;
maxX = x;
}
x = l1 - a;
dist = x * x;
if (dist < minDist) {
minAngle = PI;
minDist = dist;
minX = x;
}
angle = ACOS(-a * l1 / (aa - bb));
x = a * COS(angle) + l1;
y = b * SIN(angle);
dist = x * x + y * y;
if (dist < minDist) {
minAngle = angle;
minDist = dist;
minX = x;
minY = y;
}
if (dist > maxDist) {
maxAngle = angle;
maxDist = dist;
maxX = x;
maxY = y;
}
if (dd <= (minDist + maxDist) / 2) {
a1 = ta - ATAN2(minY * bendDir, minX);
a2 = minAngle * bendDir;
} else {
a1 = ta - ATAN2(maxY * bendDir, maxX);
a2 = maxAngle * bendDir;
}
}
outer: {
float offset = ATAN2(cy, child->x) * sign2;
a1 = (a1 - offset) * RAD_DEG + offset1;
a2 = (a2 + offset) * RAD_DEG * sign2 + offset2;
if (a1 > 180) a1 -= 360;
else if (a1 < -180) a1 += 360;
if (a2 > 180) a2 -= 360;
else if (a2 < -180) a2 += 360;
r = parent->rotation;
spBone_updateWorldTransformWith(parent, parent->x, parent->y, r + (a1 - r) * alpha, parent->scaleX, parent->scaleY);
r = child->rotation;
spBone_updateWorldTransformWith(child, child->x, cy, r + (a2 - r) * alpha, child->scaleX, child->scaleY);
}
}