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/*************************************************************************************/
/** **/
/** Copyright (c) 1999-2009 Tatewake.com **/
/** **/
/** Permission is hereby granted, free of charge, to any person obtaining a copy **/
/** of this software and associated documentation files (the "Software"), to deal **/
/** in the Software without restriction, including without limitation the rights **/
/** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell **/
/** copies of the Software, and to permit persons to whom the Software is **/
/** furnished to do so, subject to the following conditions: **/
/** **/
/** The above copyright notice and this permission notice shall be included in **/
/** all copies or substantial portions of the Software. **/
/** **/
/** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR **/
/** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, **/
/** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE **/
/** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER **/
/** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, **/
/** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN **/
/** THE SOFTWARE. **/
/** **/
/*************************************************************************************/
#include <glcomp/glcompdefs.h>
#define ARCBALL_C
#include "smyrnadefs.h"
#include "arcball.h"
static void setBounds(ArcBall_t *a, float NewWidth, float NewHeight) {
assert((NewWidth > 1.0f) && (NewHeight > 1.0f));
//Set adjustment factor for width/height
a->AdjustWidth = 1.0f / ((NewWidth - 1.0f) * 0.5f);
a->AdjustHeight = 1.0f / ((NewHeight - 1.0f) * 0.5f);
}
static Vector3fT mapToSphere(ArcBall_t *a, const Point2fT *NewPt) {
Point2fT TempPt;
//Copy paramter into temp point
TempPt = *NewPt;
//Adjust point coords and scale down to range of [-1 ... 1]
TempPt.X = TempPt.X * a->AdjustWidth - 1.0f;
TempPt.Y = 1.0f - TempPt.Y * a->AdjustHeight;
//Compute the square of the length of the vector to the point from the center
float length = TempPt.X * TempPt.X + TempPt.Y * TempPt.Y;
//If the point is mapped outside of the sphere... (length > radius squared)
if (length > 1.0f) {
//Compute a normalizing factor (radius / sqrt(length))
float norm = 1.0f / FuncSqrt(length);
//Return the "normalized" vector, a point on the sphere
return (Vector3fT){.X = TempPt.X * norm, .Y = TempPt.Y * norm};
} else //Else it's on the inside
{
//Return a vector to a point mapped inside the sphere sqrt(radius squared - length)
return (Vector3fT){.X = TempPt.X, .Y = TempPt.Y, .Z = FuncSqrt(1.0f - length)};
}
}
static Matrix4fT Transform = { {1.0f, 0.0f, 0.0f, 0.0f, // NEW: Final Transform
0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f}
};
static Matrix3fT LastRot = { {1.0f, 0.0f, 0.0f, // NEW: Last Rotation
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f}
};
static Matrix3fT ThisRot = { {1.0f, 0.0f, 0.0f, // NEW: This Rotation
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f}
};
//Create/Destroy
ArcBall_t init_arcBall(float NewWidth, float NewHeight) {
ArcBall_t a = {.Transform = Transform, .LastRot = LastRot,
.ThisRot = ThisRot};
//Set initial bounds
setBounds(&a, NewWidth, NewHeight);
return a;
}
//Mouse down
static void click(ArcBall_t * a, const Point2fT * NewPt)
{
//Map the point to the sphere
a->StVec = mapToSphere(a, NewPt);
}
//Mouse drag, calculate rotation
static Quat4fT drag(ArcBall_t *a, const Point2fT *NewPt) {
//Map the point to the sphere
a->EnVec = mapToSphere(a, NewPt);
//Return the quaternion equivalent to the rotation
// compute the vector perpendicular to the begin and end vectors
const Vector3fT Perp = Vector3fCross(a->StVec, a->EnVec);
// compute the length of the perpendicular vector
if (Vector3fLength(Perp) > Epsilon) { // if it’s non-zero
// we're OK, so return the perpendicular vector as the transform after
// all
return (Quat4fT){.X = Perp.X,
.Y = Perp.Y,
.Z = Perp.Z,
// in the quaternion values, W is cosine (theta / 2), where theta is
// rotation angle
.W = Vector3fDot(a->StVec, a->EnVec)};
} else { // if it’s zero
// the begin and end vectors coincide, so return an identity transform
return (Quat4fT){0};
}
}
void arcmouseClick(void)
{
view->arcball->isDragging = 1; // Prepare For Dragging
view->arcball->LastRot = view->arcball->ThisRot; // Set Last Static Rotation To Last Dynamic One
click(view->arcball, &view->arcball->MousePt);
}
void arcmouseDrag(void)
{
Quat4fT ThisQuat = drag(view->arcball, &view->arcball->MousePt);
view->arcball->ThisRot = Matrix3fSetRotationFromQuat4f(ThisQuat); // Convert Quaternion Into Matrix3fT
Matrix3fMulMatrix3f(&view->arcball->ThisRot, view->arcball->LastRot); // Accumulate Last Rotation Into This One
Matrix4fSetRotationFromMatrix3f(&view->arcball->Transform, &view->arcball->ThisRot); // Set Our Final Transform's Rotation From This One
}
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