Todo [#5743] Rotate dosnt work at high zoom

Fixed by only conditionally resetting the start of the triangle used to calculate the angle to when an angle is actually measured (so really small angle don't result in continuous deltas of 0 degree).

However, the smallest rotation angle is still limited by the precision of the acos function (here: 0.02 degrees, 0.02 / 30 with Shift pressed).

1 files changed, 38 insertions, 82 deletions

diff --git a/source/blender/src/transform.c b/source/blender/src/transform.c
index 6e4641a4d12..0b3cd92c565 100644
--- a/source/blender/src/transform.c
+++ b/source/blender/src/transform.c
@@ -243,6 +243,41 @@ float InputVerticalAbsolute(TransInfo *t, short mval[2]) {
 	return Inpf(t->viewinv[1], vec) * 2.0f;
 }
 
+float InputDeltaAngle(TransInfo *t, short mval[2])
+{
+	double dx2 = t->center2d[0] - mval[0];
+	double dy2 = t->center2d[1] - mval[1];
+	double B = sqrt(dx2*dx2+dy2*dy2);
+
+	double dx1 = t->center2d[0] - t->imval[0];
+	double dy1 = t->center2d[1] - t->imval[1];
+	double A = sqrt(dx1*dx1+dy1*dy1);
+
+	double dx3 = mval[0] - t->imval[0];
+	double dy3 = mval[1] - t->imval[1];
+
+	/* use doubles here, to make sure a "1.0" (no rotation) doesnt become 9.999999e-01, which gives 0.02 for acos */
+	double deler = ((dx1*dx1+dy1*dy1)+(dx2*dx2+dy2*dy2)-(dx3*dx3+dy3*dy3))
+		/ (2.0 * (A*B?A*B:1.0));
+	/* (A*B?A*B:1.0f) this takes care of potential divide by zero errors */
+
+	float dphi;
+	
+	dphi = saacos((float)deler);
+	if( (dx1*dy2-dx2*dy1)>0.0 ) dphi= -dphi;
+	
+	if(t->flag & T_SHIFT_MOD) dphi = dphi/30.0f;
+	
+	/* if no delta angle, don't update initial position */
+	if (dphi != 0)
+	{
+		t->imval[0] = mval[0];
+		t->imval[1] = mval[1];
+	}
+	
+	return dphi;
+}
+
 /* ************************** SPACE DEPENDANT CODE **************************** */
 
 void setTransformViewMatrices(TransInfo *t)
@@ -2584,23 +2619,6 @@ int Rotation(TransInfo *t, short mval[2])
 
 	float final;
 
-	double dx2 = t->center2d[0] - mval[0];
-	double dy2 = t->center2d[1] - mval[1];
-	double B = sqrt(dx2*dx2+dy2*dy2);
-
-	double dx1 = t->center2d[0] - t->imval[0];
-	double dy1 = t->center2d[1] - t->imval[1];
-	double A = sqrt(dx1*dx1+dy1*dy1);
-
-	double dx3 = mval[0] - t->imval[0];
-	double dy3 = mval[1] - t->imval[1];
-		/* use doubles here, to make sure a "1.0" (no rotation) doesnt become 9.999999e-01, which gives 0.02 for acos */
-	double deler= ((double)((dx1*dx1+dy1*dy1)+(dx2*dx2+dy2*dy2)-(dx3*dx3+dy3*dy3) ))
-		/ (2.0 * (A*B?A*B:1.0));
-	/* (A*B?A*B:1.0f) this takes care of potential divide by zero errors */
-
-	float dphi;
-
 	float axis[3];
 	float mat[3][3];
 
@@ -2608,19 +2626,7 @@ int Rotation(TransInfo *t, short mval[2])
 	VecMulf(axis, -1.0f);
 	Normalize(axis);
 
-	dphi = saacos((float)deler);
-	if( (dx1*dy2-dx2*dy1)>0.0 ) dphi= -dphi;
-
-	if(t->flag & T_SHIFT_MOD) t->fac += dphi/30.0f;
-	else t->fac += dphi;
-
-	/*
-	clamping angle between -2 PI and 2 PI (not sure if useful so commented out - theeth)
-	if (t->fac >= 2 * M_PI)
-		t->fac -= 2 * M_PI;
-	else if (t->fac <= -2 * M_PI)
-		t->fac -= -2 * M_PI;
-	*/
+	t->fac += InputDeltaAngle(t, mval);
 
 	final = t->fac;
 
@@ -2628,9 +2634,6 @@ int Rotation(TransInfo *t, short mval[2])
 	
 	snapGrid(t, &final);
 
-	t->imval[0] = mval[0];
-	t->imval[1] = mval[1];
-
 	if (t->con.applyRot) {
 		t->con.applyRot(t, NULL, axis);
 	}
@@ -3097,27 +3100,7 @@ int Tilt(TransInfo *t, short mval[2])
 
 	float final;
 
-	double dx2 = t->center2d[0] - mval[0];
-	double dy2 = t->center2d[1] - mval[1];
-	double B = (float)sqrt(dx2*dx2+dy2*dy2);
-
-	double dx1 = t->center2d[0] - t->imval[0];
-	double dy1 = t->center2d[1] - t->imval[1];
-	double A = (float)sqrt(dx1*dx1+dy1*dy1);
-
-	double dx3 = mval[0] - t->imval[0];
-	double dy3 = mval[1] - t->imval[1];
-
-	double deler= ((dx1*dx1+dy1*dy1)+(dx2*dx2+dy2*dy2)-(dx3*dx3+dy3*dy3))
-		/ (2 * A * B);
-
-	float dphi;
-
-	dphi = saacos((float)deler);
-	if( (dx1*dy2-dx2*dy1)>0.0 ) dphi= -dphi;
-
-	if(G.qual & LR_SHIFTKEY) t->fac += dphi/30.0f;
-	else t->fac += dphi;
+	t->fac += InputDeltaAngle(t, mval);
 
 	final = t->fac;
 	
@@ -3125,9 +3108,6 @@ int Tilt(TransInfo *t, short mval[2])
 
 	snapGrid(t, &final);
 
-	t->imval[0] = mval[0];
-	t->imval[1] = mval[1];
-
 	if (hasNumInput(&t->num)) {
 		char c[20];
 
@@ -3899,36 +3879,12 @@ int BoneRoll(TransInfo *t, short mval[2])
 
 	float final;
 
-	double dx2 = t->center2d[0] - mval[0];
-	double dy2 = t->center2d[1] - mval[1];
-	double B = sqrt(dx2*dx2+dy2*dy2);
-
-	double dx1 = t->center2d[0] - t->imval[0];
-	double dy1 = t->center2d[1] - t->imval[1];
-	double A = sqrt(dx1*dx1+dy1*dy1);
-
-	double dx3 = mval[0] - t->imval[0];
-	double dy3 = mval[1] - t->imval[1];
-		/* use doubles here, to make sure a "1.0" (no rotation) doesnt become 9.999999e-01, which gives 0.02 for acos */
-	double deler= ((double)((dx1*dx1+dy1*dy1)+(dx2*dx2+dy2*dy2)-(dx3*dx3+dy3*dy3) ))
-		/ (2.0 * (A*B?A*B:1.0));
-	/* (A*B?A*B:1.0f) this takes care of potential divide by zero errors */
-
-	float dphi;
-	
-	dphi = saacos((float)deler);
-	if( (dx1*dy2-dx2*dy1)>0.0 ) dphi= -dphi;
-
-	if(G.qual & LR_SHIFTKEY) t->fac += dphi/30.0f;
-	else t->fac += dphi;
+	t->fac += InputDeltaAngle(t, mval);
 
 	final = t->fac;
 
 	snapGrid(t, &final);
 
-	t->imval[0] = mval[0];
-	t->imval[1] = mval[1];
-
 	if (hasNumInput(&t->num)) {
 		char c[20];