Revert CParticle::CheckChannel changes

I misinterpreted this as being a bug, while actually it seems to be an explicit CParticle design choice (maybe not the best one, but whatever). We DO need better docs for some old code like this :/

Fixes #806

This reverts commit 99a831a03b.

src/graphics/engine/particle.cpp

@@ -581,7 +581,7 @@ int CParticle::CreateTrack(Math::Vector pos, Math::Vector speed, Math::Point dim
         if (!m_track[i].used)  // free?
         {
             int rank = channel;
-            GetRankFromChannel(rank);
+            if (!CheckChannel(rank)) return -1;
             m_particle[rank].trackRank = i;
 
             m_track[i].used = true;
@@ -636,27 +636,28 @@ void CParticle::CreateWheelTrace(const Math::Vector &p1, const Math::Vector &p2,
 
 
 
-void CParticle::GetRankFromChannel(int &channel)
+/** Adapts the channel so it can be used as an offset in m_particle */
+bool CParticle::CheckChannel(int &channel)
 {
     int uniqueStamp = (channel>>16)&0xffff;
     channel &= 0xffff;
 
-    if (channel < 0 || channel >= MAXPARTICULE*MAXPARTITYPE) throw std::runtime_error("Tried to access invalid particle channel (invalid ID)");
+    if (channel < 0)  return false;
-    if (!m_particle[channel].used) throw std::runtime_error("Tried to access invalid particle channel (used=false)");
+    if (channel >= MAXPARTICULE*MAXPARTITYPE) return false;
-    if (m_particle[channel].uniqueStamp != uniqueStamp) throw std::runtime_error("Tried to access invalid particle channel (uniqueStamp changed)");
-}
 
-bool CParticle::ParticleExists(int channel)
+    if (!m_particle[channel].used)
-{
-    try
-    {
-        GetRankFromChannel(channel);
-        return true;
-    }
-    catch (const std::runtime_error& e)
     {
+        GetLogger()->Trace("Particle %d:%d doesn't exist anymore (used=false)\n", channel, uniqueStamp);
         return false;
     }
+
+    if (m_particle[channel].uniqueStamp != uniqueStamp)
+    {
+        GetLogger()->Trace("Particle %d:%d doesn't exist anymore (uniqueStamp changed)\n", channel, uniqueStamp);
+        return false;
+    }
+
+    return true;
 }
 
 void CParticle::DeleteRank(int rank)
@@ -684,7 +685,7 @@ void CParticle::DeleteParticle(ParticleType type)
 
 void CParticle::DeleteParticle(int channel)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel)) return;
 
     if (m_totalInterface[channel/MAXPARTICULE][m_particle[channel].sheet] > 0 )
         m_totalInterface[channel/MAXPARTICULE][m_particle[channel].sheet]--;
@@ -698,50 +699,50 @@ void CParticle::DeleteParticle(int channel)
 
 void CParticle::SetObjectLink(int channel, CObject *object)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].objLink = object;
 }
 
 void CParticle::SetObjectFather(int channel, CObject *object)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].objFather = object;
 }
 
 void CParticle::SetPosition(int channel, Math::Vector pos)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].pos = pos;
 }
 
 void CParticle::SetDimension(int channel, Math::Point dim)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].dim = dim;
 }
 
 void CParticle::SetZoom(int channel, float zoom)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].zoom = zoom;
 }
 
 void CParticle::SetAngle(int channel, float angle)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].angle = angle;
 }
 
 void CParticle::SetIntensity(int channel, float intensity)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].intensity = intensity;
 }
 
 void CParticle::SetParam(int channel, Math::Vector pos, Math::Point dim, float zoom,
                           float angle, float intensity)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].pos       = pos;
     m_particle[channel].dim       = dim;
     m_particle[channel].zoom      = zoom;
@@ -751,16 +752,17 @@ void CParticle::SetParam(int channel, Math::Vector pos, Math::Point dim, float z
 
 void CParticle::SetPhase(int channel, ParticlePhase phase, float duration)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return;
     m_particle[channel].phase = phase;
     m_particle[channel].duration = duration;
     m_particle[channel].phaseTime = m_particle[channel].time;
 }
 
-Math::Vector CParticle::GetPosition(int channel)
+bool CParticle::GetPosition(int channel, Math::Vector &pos)
 {
-    GetRankFromChannel(channel);
+    if (!CheckChannel(channel))  return false;
-    return m_particle[channel].pos;
+    pos = m_particle[channel].pos;
+    return true;
 }
 
 void CParticle::SetFrameUpdate(int sheet, bool update)

src/graphics/engine/particle.h

@@ -162,9 +162,9 @@ enum ParticlePhase
 
 struct Particle
 {
-    bool            used = false;      //!< true if this channel is used, false if not
+    bool            used = false;      // TRUE -> particle used
     bool            ray = false;       // TRUE -> ray with goal
-    unsigned short  uniqueStamp = 0;    //!< unique marker added to particle channel ID to make sure this is still the same particle
+    unsigned short  uniqueStamp = 0;    // unique mark
     short           sheet = 0;      // sheet (0..n)
     ParticleType    type = {};       // type PARTI*
     ParticlePhase   phase = {};      // phase PARPH*
@@ -279,7 +279,7 @@ public:
     void        SetPhase(int channel, ParticlePhase phase, float duration);
 
     //! Returns the position of the particle
-    Math::Vector GetPosition(int channel);
+    bool        GetPosition(int channel, Math::Vector &pos);
 
     //! Returns the color if you're in the fog or black if you're not
     Color       GetFogColor(Math::Vector pos);
@@ -291,18 +291,15 @@ public:
     //! Draws all the particles
     void        DrawParticle(int sheet);
 
-    //! Checks if given particle channel still exists
-    bool        ParticleExists(int channel);
-
 protected:
     //! Removes a particle of given rank
     void        DeleteRank(int rank);
     /**
      * \brief Adapts the channel so it can be used as an offset in m_particle
      * \param channel Channel number to process, will be modified to be index of particle in m_particle
-     * \throw std::runtime_error if this particle does not exist any more
+     * \return true if success, false if particle doesn't exist anymore
      **/
-    void        GetRankFromChannel(int &channel);
+    bool        CheckChannel(int &channel);
     //! Draws a triangular particle
     void        DrawParticleTriangle(int i);
     //! Draw a normal particle

src/object/old_object.cpp

@@ -2185,17 +2185,15 @@ void COldObject::PartiFrame(float rTime)
         channel = m_objectPart[i].masterParti;
         if ( channel == -1 )  continue;
 
-        if ( !m_particle->ParticleExists(channel) )
+        if ( !m_particle->GetPosition(channel, pos) )
         {
             m_objectPart[i].masterParti = -1;  // particle no longer exists!
             continue;
         }
 
-        pos = m_particle->GetPosition(channel);
-
         SetPartPosition(i, pos);
 
-        // Each part rotates differently
+        // Each song spins differently.
         switch( i%5 )
         {
             case 0:  factor = Math::Vector( 0.5f, 0.3f, 0.6f); break;

src/object/old_object.h

@@ -55,9 +55,9 @@ const int OBJECTMAXPART         = 40;
 struct ObjectPart
 {
     bool         bUsed = false;
-    int          object = -1;         //!< identifier of the object in Gfx::CEngine
+    int          object = -1;         // number of the object in CEngine
-    int          parentPart = -1;     //!< identifier of parent part
+    int          parentPart = -1;     // number of father part
-    int          masterParti = -1;    //!< particle channel this part is connected to after explosion
+    int          masterParti = -1;        // master canal of the particle
     Math::Vector position;
     Math::Vector angle;
     Math::Vector zoom;