new stuff

assimp/tools/assimp_view/AnimEvaluator.cpp

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+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2026, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"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 THE COPYRIGHT
+OWNER OR CONTRIBUTORS 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 "AnimEvaluator.h"
+
+#include <assimp/anim.h>
+#include <assimp/ai_assert.h>
+
+using namespace AssimpView;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor on a given animation.
+AnimEvaluator::AnimEvaluator(const aiAnimation *pAnim) :
+        mAnim(pAnim),
+        mLastTime(0.0) {
+    ai_assert(nullptr != pAnim);
+    mLastPositions.resize(pAnim->mNumChannels, std::make_tuple(0, 0, 0));
+}
+
+// ------------------------------------------------------------------------------------------------
+// Evaluates the animation tracks for a given time stamp.
+void AnimEvaluator::Evaluate(double pTime) {
+    // extract ticks per second. Assume default value if not given
+    double ticksPerSecond = mAnim->mTicksPerSecond != 0.0 ? mAnim->mTicksPerSecond : 25.0;
+    // every following time calculation happens in ticks
+    pTime *= ticksPerSecond;
+
+    // map into anim's duration
+    double time = 0.0f;
+    if (mAnim->mDuration > 0.0) {
+        time = fmod(pTime, mAnim->mDuration);
+    }
+
+    if (mTransforms.size() != mAnim->mNumChannels) {
+        mTransforms.resize(mAnim->mNumChannels);
+    }
+
+    // calculate the transformations for each animation channel
+    for (unsigned int a = 0; a < mAnim->mNumChannels; ++a) {
+        const aiNodeAnim *channel = mAnim->mChannels[a];
+
+        // ******** Position *****
+        aiVector3D presentPosition(0, 0, 0);
+        if (channel->mNumPositionKeys > 0) {
+            // Look for present frame number. Search from last position if time is after the last time, else from beginning
+            // Should be much quicker than always looking from start for the average use case.
+            unsigned int frame = (time >= mLastTime) ? std::get<0>(mLastPositions[a]) : 0;
+            while (frame < channel->mNumPositionKeys - 1) {
+                if (time < channel->mPositionKeys[frame + 1].mTime) {
+                    break;
+                }
+                ++frame;
+            }
+
+            // interpolate between this frame's value and next frame's value
+            unsigned int nextFrame = (frame + 1) % channel->mNumPositionKeys;
+            const aiVectorKey &key = channel->mPositionKeys[frame];
+            const aiVectorKey &nextKey = channel->mPositionKeys[nextFrame];
+            double diffTime = nextKey.mTime - key.mTime;
+            if (diffTime < 0.0) {
+                diffTime += mAnim->mDuration;
+            }
+            if (diffTime > 0) {
+                float factor = float((time - key.mTime) / diffTime);
+                presentPosition = key.mValue + (nextKey.mValue - key.mValue) * factor;
+            } else {
+                presentPosition = key.mValue;
+            }
+
+            std::get<0>(mLastPositions[a]) = frame;
+        }
+
+        // ******** Rotation *********
+        aiQuaternion presentRotation(1, 0, 0, 0);
+        if (channel->mNumRotationKeys > 0) {
+            unsigned int frame = (time >= mLastTime) ? std::get<1>(mLastPositions[a]) : 0;
+            while (frame < channel->mNumRotationKeys - 1) {
+                if (time < channel->mRotationKeys[frame + 1].mTime) {
+                    break;
+                }
+                ++frame;
+            }
+
+            // interpolate between this frame's value and next frame's value
+            unsigned int nextFrame = (frame + 1) % channel->mNumRotationKeys;
+            const aiQuatKey &key = channel->mRotationKeys[frame];
+            const aiQuatKey &nextKey = channel->mRotationKeys[nextFrame];
+            double diffTime = nextKey.mTime - key.mTime;
+            if (diffTime < 0.0) {
+                diffTime += mAnim->mDuration;
+            }
+            if (diffTime > 0) {
+                float factor = float((time - key.mTime) / diffTime);
+                aiQuaternion::Interpolate(presentRotation, key.mValue, nextKey.mValue, factor);
+            } else {
+                presentRotation = key.mValue;
+            }
+
+            std::get<1>(mLastPositions[a]) = frame;
+        }
+
+        // ******** Scaling **********
+        aiVector3D presentScaling(1, 1, 1);
+        if (channel->mNumScalingKeys > 0) {
+            unsigned int frame = (time >= mLastTime) ? std::get<2>(mLastPositions[a]) : 0;
+            while (frame < channel->mNumScalingKeys - 1) {
+                if (time < channel->mScalingKeys[frame + 1].mTime) {
+                    break;
+                }
+                ++frame;
+            }
+
+            // TODO: (thom) interpolation maybe? This time maybe even logarithmic, not linear
+            presentScaling = channel->mScalingKeys[frame].mValue;
+            std::get<2>(mLastPositions[a]) = frame;
+        }
+
+        // build a transformation matrix from it
+        aiMatrix4x4 &mat = mTransforms[a];
+        mat = aiMatrix4x4(presentRotation.GetMatrix());
+        mat.a1 *= presentScaling.x;
+        mat.b1 *= presentScaling.x;
+        mat.c1 *= presentScaling.x;
+        mat.a2 *= presentScaling.y;
+        mat.b2 *= presentScaling.y;
+        mat.c2 *= presentScaling.y;
+        mat.a3 *= presentScaling.z;
+        mat.b3 *= presentScaling.z;
+        mat.c3 *= presentScaling.z;
+        mat.a4 = presentPosition.x;
+        mat.b4 = presentPosition.y;
+        mat.c4 = presentPosition.z;
+    }
+
+    mLastTime = time;
+}