fix: correct bounds for geometries (#35)

* Get correct bounds on geometries

* Add a unit test for combining the edges

src/plotGeometry.cpp

@@ -2,6 +2,7 @@
 // Copyright (c) 2024 Team Dissolve and contributors
 
 #include "plotGeometry.h"
+#include <algorithm>
 
 PlotGeometry::PlotGeometry() : xAxis_(nullptr), yAxis_(nullptr)
 {
@@ -43,9 +44,13 @@ void PlotGeometry::updateData()
         p = t.writeByteArray(p);
     }
 
+    std::vector<Edge> boxes(ts.size());
+    std::transform(ts.begin(), ts.end(), boxes.begin(), [](const auto x) { return x.bounds(); });
+    auto bounds = std::reduce(boxes.begin(), boxes.end(), boxes[0], [](const auto a, const auto b) { return a.combine(b); });
+
     setVertexData(vertexData);
     setStride(stride);
-    setBounds(QVector3D(-1.0f, -1.0f, 0.0f), QVector3D(+1.0f, +1.0f, 0.0f));
+    setBounds(QVector3D(bounds.start.x, bounds.start.y, bounds.start.z), QVector3D(bounds.end.x, bounds.end.y, bounds.end.z));
 
     // setPrimitiveType(QQuick3DGeometry::PrimitiveType::TriangleStrip);
 
@@ -58,15 +63,6 @@ std::vector<Triangle> PlotGeometry::faces_([[maybe_unused]] std::vector<Point> p
 
 bool outOfBounds(const Point &p) { return p.x < -1 || p.x > 1 || p.y < -1 || p.y > 1 || p.z < -1 || p.z > 1; }
 
-/** A line segment between two vertices of a polygon */
-struct Edge
-{
-    /** The beginning point of the edge */
-    Point start;
-    /** The stopping point of the edge */
-    Point end;
-};
-
 std::optional<Edge> clipEdge(const Edge &e)
 {
     // Check if edge is entirely in within bounds

src/triangle.cpp

@@ -2,14 +2,41 @@
 // Copyright (c) 2024 Team Dissolve and contributors
 
 #include "triangle.h"
+#include <algorithm>
 
 Point::Point(float a, float b, float c) : x(a), y(b), z(c) {}
 
 bool Point::operator==(const Point &other) { return x == other.x && y == other.y && z == other.z; }
 bool Point::operator!=(const Point &other) { return x != other.x || y != other.y || z != other.z; }
 
+Edge Edge::combine(const Edge &other) const
+{
+    Edge result;
+    result.start.x = std::min(start.x, other.start.x);
+    result.start.y = std::min(start.y, other.start.y);
+    result.start.z = std::min(start.z, other.start.z);
+    result.end.x = std::max(end.x, other.end.x);
+    result.end.y = std::max(end.y, other.end.y);
+    result.end.z = std::max(end.z, other.end.z);
+    return result;
+}
+
 Triangle::Triangle(Point i, Point j, Point k) : a(i), b(j), c(k) {}
 
+Edge Triangle::bounds() const
+{
+    Edge result;
+    result.start.x = std::min({a.x, b.x, c.x});
+    result.start.y = std::min({a.y, b.y, c.y});
+    result.start.z = std::min({a.z, b.z, c.z});
+
+    result.end.x = std::max({a.x, b.x, c.x});
+    result.end.y = std::max({a.y, b.y, c.y});
+    result.end.z = std::max({a.z, b.z, c.z});
+
+    return result;
+}
+
 float *Triangle::writeByteArray(float *p)
 {
     *p++ = a.x;

src/triangle.h

@@ -18,6 +18,19 @@ class Point
     bool operator!=(const Point &other);
 };
 
+/** A line segment between two vertices of a polygon */
+class Edge
+{
+    public:
+    /** The beginning point of the edge */
+    Point start;
+    /** The stopping point of the edge */
+    Point end;
+    /** Treat two edges as the corners of a bounding box and return
+        the bouning box of their union. */
+    Edge combine(const Edge &other) const;
+};
+
 /** An individual triangle face in the mesh.  */
 class Triangle
 {
@@ -34,4 +47,6 @@ class Triangle
         have enough space to write the vertex.
      */
     float *writeByteArray(float *p);
+    /** find the bounding box of the triangle and return as the diagonal from min to max */
+    Edge bounds() const;
 };

tests/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_policy(SET CMP0054 NEW)
 find_package(GTest REQUIRED)
 include(GoogleTest)
 
-set(SOURCES axis.cpp)
+set(SOURCES axis.cpp triangles.cpp)
 add_executable(axis ${SOURCES})
 
 target_include_directories(

tests/triangles.cpp

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (c) 2024 Team Dissolve and contributors
+
+#include "triangle.h"
+#include <gtest/gtest.h>
+#include <numeric>
+
+namespace UnitTest
+{
+
+TEST(TriangleTest, Combine)
+{
+    std::vector<Triangle> ts = {{{-1, 5, 9}, {4, 8, 3}, {-7, 2, 6}}, {{1, -2, -3}, {-4, -8, -6}, {7, -5, -9}}};
+
+    std::vector<Edge> boxes(ts.size());
+    std::transform(ts.begin(), ts.end(), boxes.begin(), [](const auto x) { return x.bounds(); });
+    EXPECT_EQ(boxes[1].start.x, -4);
+    EXPECT_EQ(boxes[1].start.y, -8);
+    EXPECT_EQ(boxes[1].start.z, -9);
+    EXPECT_EQ(boxes[1].end.x, 7);
+    EXPECT_EQ(boxes[1].end.y, -2);
+    EXPECT_EQ(boxes[1].end.z, -3);
+
+    EXPECT_EQ(boxes[0].start.x, -7);
+    EXPECT_EQ(boxes[0].start.y, 2);
+    EXPECT_EQ(boxes[0].start.z, 3);
+    EXPECT_EQ(boxes[0].end.x, 4);
+    EXPECT_EQ(boxes[0].end.y, 8);
+    EXPECT_EQ(boxes[0].end.z, 9);
+
+    auto bounds = std::reduce(boxes.begin(), boxes.end(), boxes[0], [](const auto a, const auto b) { return a.combine(b); });
+
+    EXPECT_EQ(bounds.start.x, -7);
+    EXPECT_EQ(bounds.start.y, -8);
+    EXPECT_EQ(bounds.start.z, -9);
+    EXPECT_EQ(bounds.end.x, 7);
+    EXPECT_EQ(bounds.end.y, 8);
+    EXPECT_EQ(bounds.end.z, 9);
+}
+} // namespace UnitTest