Use golden angle to generate unique, distinct DDTeam colors

The DDTeam colors were previously generated in HSL by taking the team index and multiplying it by 360/64° to calculate the hue, which results in team colors being evenly distributed over the entire color range like a rainbow. However, this causes colors of adjacent teams to be very similar and therefore hard to distinguish.

Now, the hue is calculated by multiplying the team index with the golden angle (~137.50776°) and taking the modulo 360° of that. Due to the properties of the golden angle, this can generate never repeating sequences of unique colors where the adjacent colors are very distinct.

Duplicate code is reduced by adding the `CGameClient::GetDDTeamColor` function.

src/game/client/components/chat.cpp

@@ -977,7 +977,7 @@ void CChat::OnPrepareLines()
  else if(m_aLines[r].m_NameColor == TEAM_SPECTATORS)
  NameColor = ColorRGBA(0.75f, 0.5f, 0.75f, 1.f);
  else if(m_aLines[r].m_ClientID >= 0 && g_Config.m_ClChatTeamColors && m_pClient->m_Teams.Team(m_aLines[r].m_ClientID))
- NameColor = color_cast<ColorRGBA>(ColorHSLA(m_pClient->m_Teams.Team(m_aLines[r].m_ClientID) / 64.0f, 1.0f, 0.75f));
+ NameColor = m_pClient->GetDDTeamColor(m_pClient->m_Teams.Team(m_aLines[r].m_ClientID), 0.75f);
  else
  NameColor = ColorRGBA(0.8f, 0.8f, 0.8f, 1.f);
 

src/game/client/components/killmessages.cpp

@@ -278,21 +278,18 @@ void CKillMessages::OnRender()
 
  float x = StartX;
 
- ColorRGBA TColor(1.f, 1.f, 1.f, 1.f);
- ColorRGBA TOutlineColor(0.f, 0.f, 0.f, 0.3f);
-
  // render victim name
  x -= m_aKillmsgs[r].m_VictimTextWidth;
+ ColorRGBA TextColor;
  if(m_aKillmsgs[r].m_VictimID >= 0 && g_Config.m_ClChatTeamColors && m_aKillmsgs[r].m_VictimDDTeam)
- {
- TColor = color_cast<ColorRGBA>(ColorHSLA(m_aKillmsgs[r].m_VictimDDTeam / 64.0f, 1.0f, 0.75f));
- TColor.a = 1.f;
- }
+ TextColor = m_pClient->GetDDTeamColor(m_aKillmsgs[r].m_VictimDDTeam, 0.75f);
+ else
+ TextColor = TextRender()->DefaultTextColor();
 
  CreateKillmessageNamesIfNotCreated(m_aKillmsgs[r]);
 
  if(m_aKillmsgs[r].m_VictimTextContainerIndex.Valid())
- TextRender()->RenderTextContainer(m_aKillmsgs[r].m_VictimTextContainerIndex, TColor, TOutlineColor, x, y + (46.f - 36.f) / 2.f);
+ TextRender()->RenderTextContainer(m_aKillmsgs[r].m_VictimTextContainerIndex, TextColor, TextRender()->DefaultTextOutlineColor(), x, y + (46.f - 36.f) / 2.f);
 
  // render victim tee
  x -= 24.0f;
@@ -380,7 +377,7 @@ void CKillMessages::OnRender()
  x -= m_aKillmsgs[r].m_KillerTextWidth;
 
  if(m_aKillmsgs[r].m_KillerTextContainerIndex.Valid())
- TextRender()->RenderTextContainer(m_aKillmsgs[r].m_KillerTextContainerIndex, TColor, TOutlineColor, x, y + (46.f - 36.f) / 2.f);
+ TextRender()->RenderTextContainer(m_aKillmsgs[r].m_KillerTextContainerIndex, TextColor, TextRender()->DefaultTextOutlineColor(), x, y + (46.f - 36.f) / 2.f);
  }
 
  y += 46.0f;

src/game/client/components/nameplates.cpp

@@ -144,7 +144,7 @@ void CNamePlates::RenderNameplatePos(vec2 Position, const CNetObj_PlayerInfo *pP
 
  float tw = m_aNamePlates[ClientID].m_NameTextWidth;
  if(g_Config.m_ClNameplatesTeamcolors && m_pClient->m_Teams.Team(ClientID))
- rgb = color_cast<ColorRGBA>(ColorHSLA(m_pClient->m_Teams.Team(ClientID) / 64.0f, 1.0f, 0.75f));
+ rgb = m_pClient->GetDDTeamColor(m_pClient->m_Teams.Team(ClientID), 0.75f);
 
  ColorRGBA TColor;
  ColorRGBA TOutlineColor;

src/game/client/components/scoreboard.cpp

@@ -355,7 +355,7 @@ void CScoreboard::RenderScoreboard(float x, float y, float w, int Team, const ch
 
  if(DDTeam != TEAM_FLOCK)
  {
- ColorRGBA Color = color_cast<ColorRGBA>(ColorHSLA(DDTeam / 64.0f, 1.0f, 0.5f, 0.5f));
+ const ColorRGBA Color = m_pClient->GetDDTeamColor(DDTeam).WithAlpha(0.5f);
  int Corners = 0;
  if(OldDDTeam != DDTeam)
  Corners |= IGraphics::CORNER_TL | IGraphics::CORNER_TR;

src/game/client/components/spectator.cpp

@@ -401,7 +401,7 @@ void CSpectator::OnRender()
 
  if(DDTeam != TEAM_FLOCK)
  {
- ColorRGBA Color = color_cast<ColorRGBA>(ColorHSLA(DDTeam / 64.0f, 1.0f, 0.5f, 0.5f));
+ const ColorRGBA Color = m_pClient->GetDDTeamColor(DDTeam).WithAlpha(0.5f);
  int Corners = 0;
  if(OldDDTeam != DDTeam)
  Corners |= IGraphics::CORNER_TL | IGraphics::CORNER_TR;

src/game/client/gameclient.cpp

@@ -765,6 +765,14 @@ bool CGameClient::Predict() const
  return !m_Snap.m_SpecInfo.m_Active && m_Snap.m_pLocalCharacter;
 }
 
+ColorRGBA CGameClient::GetDDTeamColor(int DDTeam, float Lightness) const
+{
+ // Use golden angle to generate unique colors with distinct adjacent colors.
+ // The first DDTeam (team 1) gets angle 0°, i.e. red hue.
+ const float Hue = std::fmod((DDTeam - 1) * (137.50776f / 360.0f), 1.0f);
+ return color_cast<ColorRGBA>(ColorHSLA(Hue, 1.0f, Lightness));
+}
+
 void CGameClient::OnRelease()
 {
  // release all systems

src/game/client/gameclient.h

@@ -530,6 +530,7 @@ class CGameClient : public IGameClient
  bool Predict() const;
  bool PredictDummy() { return g_Config.m_ClPredictDummy && Client()->DummyConnected() && m_Snap.m_LocalClientID >= 0 && m_PredictedDummyID >= 0 && !m_aClients[m_PredictedDummyID].m_Paused; }
  const CTuningParams *GetTuning(int i) { return &m_aTuningList[i]; }
+ ColorRGBA GetDDTeamColor(int DDTeam, float Lightness = 0.5f) const;
 
  CGameWorld m_GameWorld;
  CGameWorld m_PredictedWorld;