Added SpaceGridIterator for SpaceSegment

src/basics/SpaceGridIterator.cpp

@@ -0,0 +1,5 @@
+#include "SpaceGridIterator.h"
+
+SpaceGridIterator::SpaceGridIterator()
+{
+}

src/basics/SpaceGridIterator.h

@@ -0,0 +1,30 @@
+#ifndef SPACEGRIDITERATOR_H
+#define SPACEGRIDITERATOR_H
+
+#include "basics_global.h"
+
+namespace paysages {
+namespace basics {
+
+/**
+ * Iterator delegate that can receive sequential grid coordinates.
+ *
+ * This may be useful for ray marching algorithms for example.
+ */
+class BASICSSHARED_EXPORT SpaceGridIterator
+{
+public:
+    SpaceGridIterator();
+
+    /**
+     * Abstract method to implement to receive grid coordinates.
+     *
+     * Return false to interrupt the iteration, true to continue.
+     */
+    virtual bool onCell(int x, int y, int z) = 0;
+};
+
+}
+}
+
+#endif // SPACEGRIDITERATOR_H

src/basics/SpaceSegment.cpp

@@ -1,5 +1,8 @@
 #include "SpaceSegment.h"
 
+#include <climits>
+#include "SpaceGridIterator.h"
+
 SpaceSegment::SpaceSegment(const Vector3& start, const Vector3& end):
     start(start), end(end)
 {
@@ -54,3 +57,81 @@ bool SpaceSegment::intersectYInterval(double ymin, double ymax)
 
     return true;
 }
+
+SpaceSegment SpaceSegment::projectedOnXPlane(double x) const
+{
+    return SpaceSegment(Vector3(x, start.y, start.z), Vector3(x, end.y, end.z));
+}
+
+SpaceSegment SpaceSegment::projectedOnYPlane(double y) const
+{
+    return SpaceSegment(Vector3(start.x, y, start.z), Vector3(end.x, y, end.z));
+}
+
+SpaceSegment SpaceSegment::projectedOnZPlane(double z) const
+{
+    return SpaceSegment(Vector3(start.x, start.y, z), Vector3(end.x, end.y, z));
+}
+
+SpaceSegment SpaceSegment::scaled(double factor) const
+{
+    return SpaceSegment(start.scale(factor), end.scale(factor));
+}
+
+bool SpaceSegment::iterateOnGrid(SpaceGridIterator &delegate)
+{
+    Vector3 diff = end.sub(start);
+
+    int stepX = diff.x < 0.0 ? -1 : 1;
+    int stepY = diff.y < 0.0 ? -1 : 1;
+    int stepZ = diff.z < 0.0 ? -1 : 1;
+    int X = (int)floor(start.x);
+    int Y = (int)floor(start.y);
+    int Z = (int)floor(start.z);
+    int limitX = (int)floor(end.x) + stepX;
+    int limitY = (int)floor(end.y) + stepY;
+    int limitZ = (int)floor(end.z) + stepZ;
+    double tDeltaX = diff.x == 0.0 ? 0.0 : 1.0 / fabs(diff.x);
+    double tDeltaY = diff.y == 0.0 ? 0.0 : 1.0 / fabs(diff.y);
+    double tDeltaZ = diff.z == 0.0 ? 0.0 : 1.0 / fabs(diff.z);
+    double tMaxX = diff.x == 0.0 ? INFINITY : ((double)(X + (stepX > 0 ? 1 : 0)) - start.x) / diff.x;
+    double tMaxY = diff.y == 0.0 ? INFINITY : ((double)(Y + (stepY > 0 ? 1 : 0)) - start.y) / diff.y;
+    double tMaxZ = diff.z == 0.0 ? INFINITY : ((double)(Z + (stepZ > 0 ? 1 : 0)) - start.z) / diff.z;
+
+    do
+    {
+        if (not delegate.onCell(X, Y, Z))
+        {
+            return false;
+        }
+
+        if (tMaxX < tMaxY)
+        {
+            if (tMaxX < tMaxZ)
+            {
+                X = X + stepX;
+                tMaxX = tMaxX + tDeltaX;
+            }
+            else
+            {
+                Z = Z + stepZ;
+                tMaxZ = tMaxZ + tDeltaZ;
+            }
+        }
+        else
+        {
+            if(tMaxY < tMaxZ)
+            {
+                Y = Y + stepY;
+                tMaxY = tMaxY + tDeltaY;
+            }
+            else
+            {
+                Z= Z + stepZ;
+                tMaxZ = tMaxZ + tDeltaZ;
+            }
+        }
+    } while (X != limitX and Y != limitY and Z != limitZ);
+
+    return true;
+}

src/basics/SpaceSegment.h

@@ -8,8 +8,8 @@
 namespace paysages {
 namespace basics {
 
-/*!
- * \brief A segment in 3D space (mainly useful for rays).
+/**
+ * A delimited segment in 3D space (mainly useful for rays).
  */
 class BASICSSHARED_EXPORT SpaceSegment
 {
@@ -17,19 +17,53 @@ public:
     SpaceSegment(const Vector3& start, const Vector3& end);
     SpaceSegment(): SpaceSegment(Vector3(), Vector3()) {}
 
-    inline Vector3 getStart() const {return start;}
-    inline Vector3 getEnd() const {return end;}
+    inline const Vector3 &getStart() const {return start;}
+    inline const Vector3 &getEnd() const {return end;}
+    inline Vector3 getDirection() const {return end.sub(start);}
+    inline double getLength() const {return end.sub(start).getNorm();}
 
     inline double getXDiff() const {return end.x - start.x;}
     inline double getYDiff() const {return end.y - start.y;}
     inline double getZDiff() const {return end.z - start.z;}
 
-    /*!
-     * \brief Keep only the intersection with a slice orthogonal to the Y axis.
-     * \return true if a segment remains
+    /**
+     * Keep only the intersection with a slice orthogonal to the Y axis.
+     *
+     * Return true if a segment remains.
      */
     bool intersectYInterval(double ymin, double ymax);
 
+    /**
+     * Return a version of this segment, projected on a X plane.
+     */
+    SpaceSegment projectedOnXPlane(double x=0.0) const;
+    /**
+     * Return a version of this segment, projected on a Y plane.
+     */
+    SpaceSegment projectedOnYPlane(double y=0.0) const;
+    /**
+     * Return a version of this segment, projected on a Z plane.
+     */
+    SpaceSegment projectedOnZPlane(double z=0.0) const;
+
+    /**
+     * Return a scaled version of this segment.
+     *
+     * Pay attention, scaling is done from the coordinates origin (0,0,0), not the segment center.
+     */
+    SpaceSegment scaled(double factor) const;
+
+    /**
+     * Iterate inside a virtual grid.
+     *
+     * The space is considered as cut into 1.0-sized cubic cells,
+     * and the delegate will be called with coordinates of the cells
+     * traversed by this segment.
+     *
+     * Return false if the iteration was aborted by the delegate, true otherwise.
+     */
+    bool iterateOnGrid(SpaceGridIterator &delegate);
+
 private:
     Vector3 start;
     Vector3 end;

src/basics/basics.pro

@@ -33,7 +33,8 @@ SOURCES += \
     Texture3D.cpp \
     Texture4D.cpp \
     NoiseState.cpp \
-    FractalNoise.cpp
+    FractalNoise.cpp \
+    SpaceGridIterator.cpp
 
 HEADERS +=\
         basics_global.h \
@@ -54,7 +55,8 @@ HEADERS +=\
     Texture3D.h \
     Texture4D.h \
     NoiseState.h \
-    FractalNoise.h
+    FractalNoise.h \
+    SpaceGridIterator.h
 
 unix:!symbian {
     maemo5 {

src/basics/basics_global.h

@@ -15,6 +15,7 @@ namespace basics {
     class Vector3;
     class Matrix4;
     class BoundingBox;
+    class SpaceGridIterator;
     class SpaceSegment;
     class Color;
     class NoiseGenerator;

src/tests/SpaceSegment_Test.cpp

@@ -0,0 +1,61 @@
+#include "BaseTestCase.h"
+
+#include "SpaceSegment.h"
+#include "SpaceGridIterator.h"
+
+class CollectGridIterator: public SpaceGridIterator
+{
+public:
+    std::vector<Vector3> locations;
+protected:
+    virtual bool onCell(int x, int y, int z) override
+    {
+        locations.push_back(Vector3(x, y, z));
+        return true;
+    }
+};
+
+TEST(SpaceSegment, iterateOnGrid)
+{
+    CollectGridIterator it;
+    SpaceSegment segment(Vector3(0.5, 1.5, 0.0), Vector3(2.5, 0.5, 0.0));
+    segment.iterateOnGrid(it);
+
+    ASSERT_EQ(4, it.locations.size());
+    EXPECT_VECTOR3_COORDS(it.locations[0], 0.0, 1.0, 0.0);
+    EXPECT_VECTOR3_COORDS(it.locations[1], 1.0, 1.0, 0.0);
+    EXPECT_VECTOR3_COORDS(it.locations[2], 1.0, 0.0, 0.0);
+    EXPECT_VECTOR3_COORDS(it.locations[3], 2.0, 0.0, 0.0);
+}
+
+TEST(SpaceSegment, iterateOnGrid_Corner)
+{
+    CollectGridIterator it;
+    SpaceSegment segment(Vector3(0.5, 0.5, 0.5), Vector3(2.5, 2.5, 2.5));
+    segment.iterateOnGrid(it);
+
+    ASSERT_EQ(7, it.locations.size());
+    EXPECT_VECTOR3_COORDS(it.locations[0], 0.0, 0.0, 0.0);
+    EXPECT_VECTOR3_COORDS(it.locations[3], 1.0, 1.0, 1.0);
+    EXPECT_VECTOR3_COORDS(it.locations[6], 2.0, 2.0, 2.0);
+}
+
+TEST(SpaceSegment, iterateOnGrid_OneCell)
+{
+    CollectGridIterator it;
+    SpaceSegment segment(Vector3(8.1, 8.2, 8.9), Vector3(8.9, 8.3, 8.6));
+    segment.iterateOnGrid(it);
+
+    ASSERT_EQ(1, it.locations.size());
+    EXPECT_VECTOR3_COORDS(it.locations[0], 8.0, 8.0, 8.0);
+}
+
+TEST(SpaceSegment, iterateOnGrid_Negative)
+{
+    CollectGridIterator it;
+    SpaceSegment segment(Vector3(-8.1, -8.2, -8.9), Vector3(-8.9, -8.3, -8.6));
+    segment.iterateOnGrid(it);
+
+    ASSERT_EQ(1, it.locations.size());
+    EXPECT_VECTOR3_COORDS(it.locations[0], -9.0, -9.0, -9.0);
+}

src/tests/tests.pro

@@ -18,6 +18,7 @@ SOURCES += main.cpp \
     FluidMediumManager_Test.cpp \
     VertexArray_Test.cpp \
     FractalNoise_Test.cpp \
+    SpaceSegment_Test.cpp \
     Canvas_Test.cpp \
     CanvasPortion_Test.cpp \
     CanvasPreview_Test.cpp \