Campbell Barton
c434782e3a
Use a shorter/simpler license convention, stops the header taking so much space. Follow the SPDX license specification: https://spdx.org/licenses - C/C++/objc/objc++ - Python - Shell Scripts - CMake, GNUmakefile While most of the source tree has been included - `./extern/` was left out. - `./intern/cycles` & `./intern/atomic` are also excluded because they use different header conventions. doc/license/SPDX-license-identifiers.txt has been added to list SPDX all used identifiers. See P2788 for the script that automated these edits. Reviewed By: brecht, mont29, sergey Ref D14069
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/** \file
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* \ingroup bli
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*/
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#include "BLI_dial_2d.h"
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#include "BLI_math.h"
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#include "MEM_guardedalloc.h"
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struct Dial {
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/* center of the dial */
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float center[2];
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/* threshold of the dial. Distance of current position has to be greater
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* than the threshold to be used in any calculations */
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float threshold_squared;
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/* the direction of the first dial position exceeding the threshold. This
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* is later used as the basis against which rotation angle is calculated */
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float initial_direction[2];
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/* cache the last angle to detect rotations bigger than -/+ PI */
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float last_angle;
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/* number of full rotations */
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int rotations;
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/* has initial_direction been initialized */
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bool initialized;
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};
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Dial *BLI_dial_init(const float start_position[2], float threshold)
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{
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Dial *dial = MEM_callocN(sizeof(Dial), "dial");
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copy_v2_v2(dial->center, start_position);
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dial->threshold_squared = threshold * threshold;
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return dial;
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}
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float BLI_dial_angle(Dial *dial, const float current_position[2])
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{
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float current_direction[2];
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sub_v2_v2v2(current_direction, current_position, dial->center);
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/* only update when we have enough precision,
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* by having the mouse adequately away from center */
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if (len_squared_v2(current_direction) > dial->threshold_squared) {
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float angle;
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float cosval, sinval;
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normalize_v2(current_direction);
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if (!dial->initialized) {
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copy_v2_v2(dial->initial_direction, current_direction);
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dial->initialized = true;
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}
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/* calculate mouse angle between initial and final mouse position */
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cosval = dot_v2v2(current_direction, dial->initial_direction);
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sinval = cross_v2v2(current_direction, dial->initial_direction);
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/* Clamp to avoid NAN's in #acos */
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angle = atan2f(sinval, cosval);
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/* change of sign, we passed the 180 degree threshold. This means we need to add a turn.
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* to distinguish between transition from 0 to -1 and -PI to +PI,
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* use comparison with PI/2 */
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if ((angle * dial->last_angle < 0.0f) && (fabsf(dial->last_angle) > (float)M_PI_2)) {
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if (dial->last_angle < 0.0f) {
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dial->rotations--;
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}
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else {
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dial->rotations++;
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}
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}
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dial->last_angle = angle;
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return angle + 2.0f * (float)M_PI * dial->rotations;
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}
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return dial->last_angle;
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}
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