添加模型分割

client/gui/editor/EntityCutoutUtils.cpp

@@ -0,0 +1,110 @@
+#include "editor/EntityCutoutUtils.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include <QPainter>
+#include <QPolygonF>
+#include <QTransform>
+
+namespace entity_cutout {
+
+QPainterPath pathFromWorldPolygon(const QVector<QPointF>& poly) {
+    QPainterPath path;
+    if (poly.size() < 3) {
+        return path;
+    }
+    path.addPolygon(QPolygonF(poly));
+    path.closeSubpath();
+    return path;
+}
+
+QPointF polygonCentroid(const QVector<QPointF>& poly) {
+    if (poly.size() < 3) {
+        return {};
+    }
+    double a2 = 0.0;
+    double cx6a = 0.0;
+    double cy6a = 0.0;
+    for (int i = 0; i < poly.size(); ++i) {
+        const QPointF p0 = poly[i];
+        const QPointF p1 = poly[(i + 1) % poly.size()];
+        const double cross = static_cast<double>(p0.x()) * static_cast<double>(p1.y()) -
+                             static_cast<double>(p1.x()) * static_cast<double>(p0.y());
+        a2 += cross;
+        cx6a += (static_cast<double>(p0.x()) + static_cast<double>(p1.x())) * cross;
+        cy6a += (static_cast<double>(p0.y()) + static_cast<double>(p1.y())) * cross;
+    }
+    if (std::abs(a2) < 1e-6) {
+        const QRectF bb = pathFromWorldPolygon(poly).boundingRect();
+        return bb.center();
+    }
+    const double inv6a = 1.0 / (3.0 * a2);
+    return QPointF(cx6a * inv6a, cy6a * inv6a);
+}
+
+QRect clampRectToImage(const QRect& r, const QSize& size) {
+    QRect out = r.normalized();
+    if (out.isNull()) {
+        return {};
+    }
+    out.setLeft(std::max(0, out.left()));
+    out.setTop(std::max(0, out.top()));
+    out.setRight(std::min(size.width() - 1, out.right()));
+    out.setBottom(std::min(size.height() - 1, out.bottom()));
+    if (out.width() <= 0 || out.height() <= 0) {
+        return {};
+    }
+    return out;
+}
+
+QImage extractEntityImage(const QImage& bg, const QVector<QPointF>& polyWorld, QPointF& outTopLeftWorld) {
+    if (bg.isNull() || polyWorld.size() < 3) {
+        outTopLeftWorld = {};
+        return {};
+    }
+    const QPainterPath path = pathFromWorldPolygon(polyWorld);
+    if (path.isEmpty()) {
+        outTopLeftWorld = {};
+        return {};
+    }
+    const QRect bbox = clampRectToImage(path.boundingRect().toAlignedRect(), bg.size());
+    if (bbox.isNull()) {
+        outTopLeftWorld = {};
+        return {};
+    }
+
+    outTopLeftWorld = bbox.topLeft();
+
+    QImage out(bbox.size(), QImage::Format_ARGB32_Premultiplied);
+    out.fill(Qt::transparent);
+    QPainter p(&out);
+    p.setRenderHint(QPainter::Antialiasing, true);
+
+    QTransform tr;
+    tr.translate(-bbox.left(), -bbox.top());
+    const QPainterPath localPath = tr.map(path);
+
+    p.setClipPath(localPath);
+    p.drawImage(QPoint(0, 0), bg, bbox);
+    p.end();
+    return out;
+}
+
+void applyBlackFillToBackground(QImage& bgCutout, const QVector<QPointF>& polyWorld) {
+    if (bgCutout.isNull() || polyWorld.size() < 3) {
+        return;
+    }
+    QPainterPath path = pathFromWorldPolygon(polyWorld);
+    if (path.isEmpty()) {
+        return;
+    }
+    QPainter p(&bgCutout);
+    p.setRenderHint(QPainter::Antialiasing, true);
+    p.setPen(Qt::NoPen);
+    p.setBrush(QColor(0, 0, 0, 255));
+    p.drawPath(path);
+    p.end();
+}
+
+}  // namespace entity_cutout