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Small optimization of clipPolygonWithPlanes() function

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This commit is contained in:
Daniel Chappuis 2020-09-21 13:52:23 +02:00
parent 9e4e047796
commit 30af76dfaf
3 changed files with 40 additions and 25 deletions
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2
CMakeLists.txt
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@ -121,6 +121,7 @@ set (REACTPHYSICS3D_HEADERS
"include/reactphysics3d/collision/CollisionCallback.h"
"include/reactphysics3d/collision/OverlapCallback.h"
"include/reactphysics3d/mathematics/mathematics.h"
"include/reactphysics3d/mathematics/mathematics_common.h"
"include/reactphysics3d/mathematics/mathematics_functions.h"
"include/reactphysics3d/mathematics/Matrix2x2.h"
"include/reactphysics3d/mathematics/Matrix3x3.h"
@ -220,7 +221,6 @@ set (REACTPHYSICS3D_SOURCES
"src/components/SliderJointComponents.cpp"
"src/collision/CollisionCallback.cpp"
"src/collision/OverlapCallback.cpp"
"src/mathematics/mathematics_functions.cpp"
"src/mathematics/Matrix2x2.cpp"
"src/mathematics/Matrix3x3.cpp"
"src/mathematics/Quaternion.cpp"

10
include/reactphysics3d/containers/Array.h
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@ -387,17 +387,19 @@ class Array {
/// Remove an element from the array at a given index and replace it by the last one of the array (if any)
/// Append another array at the end of the current one
void addRange(const Array<T>& array) {
void addRange(const Array<T>& array, uint32 startIndex = 0) {
assert(startIndex <= array.size());
// If we need to allocate more memory
if (mSize + array.size() > mCapacity) {
if (mSize + (array.size() - startIndex) > mCapacity) {
// Allocate memory
reserve(mSize + array.size());
reserve(mSize + array.size() - startIndex);
}
// Add the elements of the array to the current one
for(uint32 i=0; i<array.size(); i++) {
for(uint32 i=startIndex; i<array.size(); i++) {
new (reinterpret_cast<void*>(mBuffer + mSize)) T(array[i]);
mSize++;

53
include/reactphysics3d/mathematics/mathematics_functions.h
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@ -330,32 +330,37 @@ RP3D_FORCE_INLINE Array<Vector3> clipSegmentWithPlanes(const Vector3& segA, cons
// Clip a polygon against multiple planes and return the clipped polygon vertices
// This method implements the Sutherland–Hodgman clipping algorithm
RP3D_FORCE_INLINE void clipPolygonWithPlanes(const Array<Vector3>& polygonVertices, const Array<Vector3>& planesPoints,
const Array<Vector3>& planesNormals, Array<Vector3>& outClippedPolygonVertices,
MemoryAllocator& allocator) {
const Array<Vector3>& planesNormals, Array<Vector3>& outClippedPolygonVertices,
MemoryAllocator& allocator) {
assert(planesPoints.size() == planesNormals.size());
const uint32 nbMaxElements = polygonVertices.size() + planesPoints.size();
Array<Vector3> inputVertices(allocator, nbMaxElements);
const uint32 nbPlanesPoints = planesPoints.size();
const uint32 nbMaxElements = polygonVertices.size() * 2 * nbPlanesPoints;
Array<Vector3> vertices(allocator, nbMaxElements * nbPlanesPoints);
outClippedPolygonVertices.reserve(nbMaxElements);
inputVertices.addRange(polygonVertices);
vertices.addRange(polygonVertices);
uint32 currentPolygonStartIndex = 0;
uint32 nbInputVertices = polygonVertices.size();
// For each clipping plane
const uint32 nbPlanesPoints = planesPoints.size();
for (uint32 p=0; p < nbPlanesPoints; p++) {
outClippedPolygonVertices.clear();
uint32 nextNbInputVertices = 0;
const uint32 nbInputVertices = inputVertices.size();
uint32 vStart = nbInputVertices - 1;
uint32 vStart = currentPolygonStartIndex + nbInputVertices - 1;
const decimal planeNormalDotPlanePoint = planesNormals[p].dot(planesPoints[p]);
// For each edge of the polygon
for (uint vEnd = 0; vEnd<nbInputVertices; vEnd++) {
for (uint vEnd = currentPolygonStartIndex; vEnd < currentPolygonStartIndex + nbInputVertices; vEnd++) {
Vector3& v1 = inputVertices[vStart];
Vector3& v2 = inputVertices[vEnd];
Vector3& v1 = vertices[vStart];
Vector3& v2 = vertices[vEnd];
const decimal v1DotN = (v1 - planesPoints[p]).dot(planesNormals[p]);
const decimal v2DotN = (v2 - planesPoints[p]).dot(planesNormals[p]);
@ -367,18 +372,21 @@ RP3D_FORCE_INLINE void clipPolygonWithPlanes(const Array<Vector3>& polygonVertic
if (v1DotN < decimal(0.0)) {
// The second point we keep is the intersection between the segment v1, v2 and the clipping plane
decimal t = computePlaneSegmentIntersection(v1, v2, planesNormals[p].dot(planesPoints[p]), planesNormals[p]);
const decimal t = computePlaneSegmentIntersection(v1, v2, planeNormalDotPlanePoint, planesNormals[p]);
if (t >= decimal(0) && t <= decimal(1.0)) {
outClippedPolygonVertices.add(v1 + t * (v2 - v1));
vertices.add(v1 + t * (v2 - v1));
nextNbInputVertices++;
}
else {
outClippedPolygonVertices.add(v2);
vertices.add(v2);
nextNbInputVertices++;
}
}
// Add the second vertex
outClippedPolygonVertices.add(v2);
vertices.add(v2);
nextNbInputVertices++;
}
else { // If the second vertex is behind the clipping plane
@ -386,13 +394,15 @@ RP3D_FORCE_INLINE void clipPolygonWithPlanes(const Array<Vector3>& polygonVertic
if (v1DotN >= decimal(0.0)) {
// The first point we keep is the intersection between the segment v1, v2 and the clipping plane
decimal t = computePlaneSegmentIntersection(v1, v2, -planesNormals[p].dot(planesPoints[p]), -planesNormals[p]);
const decimal t = computePlaneSegmentIntersection(v1, v2, -planeNormalDotPlanePoint, -planesNormals[p]);
if (t >= decimal(0.0) && t <= decimal(1.0)) {
outClippedPolygonVertices.add(v1 + t * (v2 - v1));
vertices.add(v1 + t * (v2 - v1));
nextNbInputVertices++;
}
else {
outClippedPolygonVertices.add(v1);
vertices.add(v1);
nextNbInputVertices++;
}
}
}
@ -400,8 +410,11 @@ RP3D_FORCE_INLINE void clipPolygonWithPlanes(const Array<Vector3>& polygonVertic
vStart = vEnd;
}
inputVertices = outClippedPolygonVertices;
currentPolygonStartIndex += nbInputVertices;
nbInputVertices = nextNbInputVertices;
}
outClippedPolygonVertices.addRange(vertices, currentPolygonStartIndex);
}
// Project a point onto a plane that is given by a point and its unit length normal