WIP - Attenuation Models

rts/Game/Camera.cpp

@@ -4,6 +4,7 @@
 
 #include "Camera.h"
 #include "CameraHandler.h"
+#include "Game/TraceRay.h"
 #include "UI/MouseHandler.h"
 #include "Map/Ground.h"
 #include "Map/ReadMap.h"
@@ -156,6 +157,8 @@ void CCamera::Update(const UpdateParams& p)
 	if (p.updateFrustum)
 		UpdateFrustum();
 
+    TraceToTerrain();
+
 	LoadMatrices();
 	// not done here
 	// LoadViewPort();
@@ -708,6 +711,24 @@ void CCamera::ClipFrustumLines(const float zmin, const float zmax, bool neg)
 	}
 }
 
+void CCamera::TraceToTerrain() {
+    if (camType != CAMTYPE_PLAYER)
+        return;
+
+    const CUnit* hitUnit = nullptr;
+    const CFeature* hitFeature = nullptr;
+
+    terrainDistance = TraceRay::GuiTraceRay(
+        GetPos(),
+        GetForward(),
+        30000,
+        nullptr,
+        hitUnit,
+        hitFeature,
+        true,
+        true
+    );
+}
 
 float3 CCamera::GetMoveVectorFromState(bool fromKeyState) const
 {
@@ -716,7 +737,7 @@ float3 CCamera::GetMoveVectorFromState(bool fromKeyState) const
 
 	if (useInterpolate > 0)
 		camDeltaTime = 1000.0f / std::fmax(globalRendering->FPS, 1.0f);
-	
+
 	float camMoveSpeed = 1.0f;
 
 	camMoveSpeed *= movState[MOVE_STATE_SLW] ? moveSlowMult : 1.0f;

rts/Game/Camera.h

@@ -202,6 +202,7 @@ class CCamera {
 	float GetNearPlaneDist() const { return frustum.scales.z; }
 	float GetFarPlaneDist() const { return frustum.scales.w; }
 	float GetAspectRatio() const { return aspectRatio; }
+    float GetTerrainDistance() const { return terrainDistance; }
 
 	float3 GetMoveVectorFromState(bool fromKeyState) const;
 
@@ -253,6 +254,7 @@ class CCamera {
 
 	void UpdateDirsFromRot(const float3& r);
 
+    void TraceToTerrain();
 public:
 	float3 pos;
 	float3 rot;                   ///< x = inclination, y = azimuth (to the -z axis!), z = roll
@@ -309,6 +311,8 @@ class CCamera {
 
 	uint8_t inViewPlanesMask;
 
+    float terrainDistance = 1000;
+
 	bool movState[10]; // fwd, back, left, right, up, down, fast, slow, tilt, reset
 	bool rotState[4]; // unused
 };

rts/System/Sound/AttenuationModels/RtsAttenuationModel.cpp

@@ -0,0 +1,69 @@
+/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
+
+#include "RtsAttenuationModel.h"
+#include "Game/Camera.h"
+#include "Game/CameraHandler.h"
+#include "System/Sound/ISoundAttenuationModel.h"
+#include "Game/TraceRay.h"
+#include <algorithm>
+#include <cmath>
+
+SoundAttenuationOutput RtsAttenuationModel::Evaluate(const SoundAttenuationInput& in) const {
+
+    SoundAttenuationOutput out;
+
+    // -----------------------------------------------------------------
+    // Convert the soundPosition in to camera space and calculate necessary data
+    // -----------------------------------------------------------------
+
+    {
+        CCamera* playerCamera = CCameraHandler::GetCamera(CCamera::CAMTYPE_PLAYER);
+
+        float terrainDistance = playerCamera->GetTerrainDistance();
+
+        out.zoomFactor = 1 - std::clamp(terrainDistance == -1 ? 1.0f : terrainDistance / GetForwardAttenuationRange(), 0.0f, 1.0f);
+        out.tiltFactor = playerCamera->GetForward().dot(float3(0.0f, -1.0f, 0.0f));
+
+        float3 toSound = in.soundPosition - playerCamera->GetPos();
+
+        float camForward = playerCamera->GetForward().dot(toSound);
+        float camRight = playerCamera->GetRight().dot(toSound);
+        float camUp = playerCamera->GetUp().dot(toSound);
+
+        out.forwardDistance = camForward;
+
+        float hfov = playerCamera->GetHFOV() * math::DEG_TO_RAD;
+        float vfov = playerCamera->GetVFOV() * math::DEG_TO_RAD;
+
+        float distance = std::abs(camForward);
+        if (distance <= 0.0f) distance = 1.0f;
+
+        out.frustumWidth = distance * std::tan(hfov * 0.5f);
+        out.frustumHeight = distance * std::tan(vfov * 0.5f);
+
+        float outsideRight = std::max(0.0f, std::abs(camRight) - out.frustumWidth);
+        float outsideUp = std::max(0.0f, std::abs(camUp) - out.frustumHeight);
+
+        out.outerDistance = std::sqrt(outsideRight * outsideRight + outsideUp * outsideUp);
+    }
+
+    // -----------------------------------------------------------------
+    // Convert all the positional data to normalized ranges and calculate the final ranges
+    // -----------------------------------------------------------------
+
+    {
+        // Calculate forward attenuation
+        float forwardValue = std::clamp(out.forwardDistance >= 0 ?
+            std::lerp(GetMinVolumeAttenuation(), 1.0f, 1.0f - out.forwardDistance / GetForwardAttenuationRange()) :
+            std::clamp(1.0f - (-out.forwardDistance) / GetBackwardAttenuationRange(), 0.0f, 1.0f), GetMinVolumeAttenuation(), 1.0f);
+
+        // Calculate outer attenuation
+        float outerValue = std::clamp(std::lerp(GetMinFilterAttenuation(), 1.0f, 1.0f - out.outerDistance / GetOuterAttenuationRange()), GetMinFilterAttenuation(), 1.0f);
+
+        out.volumeFactor = std::pow(forwardValue, 6) * outerValue;
+        out.filterFactor = std::pow(forwardValue, 1) * outerValue;
+    }
+
+    return out;
+}
+

rts/System/Sound/AttenuationModels/RtsAttenuationModel.h

@@ -0,0 +1,22 @@
+/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
+
+#pragma once
+
+#include "System/Config/ConfigHandler.h"
+#include "System/Sound/ISoundAttenuationModel.h"
+
+class RtsAttenuationModel : public ISoundAttenuationModel
+{
+public:
+    SoundAttenuationOutput Evaluate(const SoundAttenuationInput& in) const override;
+
+private:
+    float GetForwardAttenuationRange() const { return configHandler->GetFloat("snd_forwardAttenuationRange"); }
+    float GetBackwardAttenuationRange() const { return configHandler->GetFloat("snd_backwardAttenuationRange"); }
+    float GetOuterAttenuationRange() const { return configHandler->GetFloat("snd_outerAttenuationRange"); }
+    float GetMinVolumeAttenuation() const { return configHandler->GetFloat("snd_minVolumeAttenuation"); }
+    float GetMinFilterAttenuation() const { return configHandler->GetFloat("snd_minFilterAttenuation"); }
+};
+
+// "RTS Model: Designed for RTS games with viewport-based attenuation, forward/backward distance handling, off-screen attenuation, and zoom-aware center attenuation. Seen in games like \"Planetary Annihilation\" or \"Supreme Commander 2\""
+

rts/System/Sound/CMakeLists.txt

@@ -8,6 +8,7 @@ set(noSoundSources
 		ISound.cpp
 		Null/SoundChannels.cpp
 		Null/NullSound.cpp
+        AttenuationModels/RtsAttenuationModel.cpp
 	)
 
 add_library(no-sound STATIC EXCLUDE_FROM_ALL ${noSoundSources})
@@ -42,6 +43,7 @@ if    (NOT NO_SOUND)
 			OpenAL/SoundItem.cpp
 			OpenAL/SoundSource.cpp
 			OpenAL/VorbisShared.cpp
+            AttenuationModels/RtsAttenuationModel.cpp
 		)
 
 	find_package_static(OpenAL 1.18.2 REQUIRED)

rts/System/Sound/ISound.cpp

@@ -40,6 +40,12 @@ CONFIG(float, snd_airAbsorption).defaultValue(0.1f);
 
 CONFIG(std::string, snd_device).defaultValue("").description("Sets the used output device. See \"Available Devices\" section in infolog.txt.");
 
+CONFIG(bool, snd_useAttenuationModel).defaultValue(false).description("Use the new AttenuationModel system. Affects how you hear 3D sounds in the game. Recommended: ON");
+CONFIG(float, snd_forwardAttenuationRange).defaultValue(8000).description("Distance in front of the camera over which sound volume and clarity gradually fade.");
+CONFIG(float, snd_backwardAttenuationRange).defaultValue(300).description("Distance behind the camera over which sounds are attenuated.");
+CONFIG(float, snd_outerAttenuationRange).defaultValue(500).description("How far sounds can be outside the camera view before being strongly attenuated.");
+CONFIG(float, snd_minVolumeAttenuation).defaultValue(0.0f).minimumValue(0).maximumValue(1).description("Minimum volume multiplier for attenuated sounds to prevent them from becoming silent. Smaller is quieter");
+CONFIG(float, snd_minFilterAttenuation).defaultValue(0.05f).minimumValue(0).maximumValue(1).description("Minimum clarity level for attenuated sounds, controlling how muffled distant sounds become. Smaller numbers meaning more filtered");
 
 
 #ifndef NO_SOUND

rts/System/Sound/ISound.h

@@ -3,6 +3,7 @@
 #ifndef _I_SOUND_H_
 #define _I_SOUND_H_
 
+#include "System/Sound/ISoundAttenuationModel.h"
 #include <cstdint>
 #include <string>
 #include <vector>
@@ -79,6 +80,9 @@ class ISound {
 private:
 	virtual bool LoadSoundDefsImpl(LuaParser* defsParser) = 0;
 	static bool IsNullAudio();
+
+public:
+    virtual ISoundAttenuationModel* GetAttenuationModel() { return nullptr; }
 };
 
 #define sound ISound::GetInstance()

rts/System/Sound/ISoundAttenuationModel.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "System/float3.h"
+struct SoundAttenuationInput {
+    float3 soundPosition;
+    //maybe some sound specific settings like should it be resistant to attenuation
+};
+
+/// All of the data used to calculate the totalFactor as well as the final totalFactor
+struct SoundAttenuationOutput {
+    float forwardDistance;
+    float outerDistance;
+    float frustumHeight;
+    float frustumWidth;
+    float volumeFactor;
+    float filterFactor;
+    float tiltFactor;
+    float zoomFactor;
+};
+
+class ISoundAttenuationModel {
+public:
+    virtual ~ISoundAttenuationModel() = default;
+
+    virtual SoundAttenuationOutput Evaluate(
+        const SoundAttenuationInput& in
+    ) const = 0;
+};
+

rts/System/Sound/OpenAL/Sound.cpp

@@ -44,6 +44,8 @@
 
 #include "System/float3.h"
 
+#include "Rendering/GL/glExtra.h"
+
 
 spring::recursive_mutex soundMutex;
 
@@ -58,7 +60,6 @@ CSound::~CSound()
 	configHandler->RemoveObserver(this);
 }
 
-
 void CSound::Init()
 {
 	std::lock_guard<spring::recursive_mutex> lck(soundMutex);
@@ -79,6 +80,8 @@ void CSound::Init()
 		updateListener = false;
 		soundThreadQuit = false;
 		canLoadDefs = false;
+
+        attenuationModel = new RtsAttenuationModel();
 	}
 	{
 		Channels::General->SetVolume(configHandler->GetInt("snd_volgeneral") * 0.01f);
@@ -121,6 +124,9 @@ void CSound::Kill()
 			soundThread.join();
 	}
 
+    delete attenuationModel;
+    attenuationModel = nullptr;
+
 	SoundBuffer::Deinitialise();
 }
 
@@ -358,7 +364,7 @@ void CSound::DeviceChanged(uint32_t sdlDeviceIndex)
 	// In these cases, no event is emitted — SDL2 switches the active audio device internally through the OS-specific audio backend (WASAPI, PulseAudio, etc.).
 	// However, with certain device changes a short dropout may occur, and SDL2 will emit the SDL_AUDIODEVICEREMOVED event.
 	// Shortly afterwards, the default device can usually be reinitialized.
-	
+
 	// This behavior can be reproduced on several test systems, for example when switching the Windows default device from monitor audio over HDMI to a sound card (HDMI->analog)
 
 	std::lock_guard<spring::recursive_mutex> lck(soundMutex);
@@ -513,7 +519,7 @@ bool CSound::OpenSdlDevice(const std::string& deviceName, SDL_AudioSpec& obtaine
 	desiredSpec.samples = 4096;
 	desiredSpec.callback = RenderSDLSamples;
 	desiredSpec.userdata = this;
-	
+
 	/* SDL bug: can return devices with >2 channels (3D surround), even if we ask for just 2.
 	 * This causes the 2 "primary" channels to be moved in the 3D space compared to their "normal" state
 	 * and directional sound doesn't work anymore (though volume change with distance still does).
@@ -1108,3 +1114,23 @@ std::vector<std::string> CSound::GetSoundDevices()
 	}
 	return devices;
 }
+
+void CSound::DrawDebug() const
+{
+    // Only draw 3D sound sources that are currently playing
+    for (const CSoundSource& source: soundSources) {
+        // Use your extracted data functions instead of OpenAL calls
+        if (source.IsPlaying(false) && source.IsIn3D()) {
+            // Get position using your accessor methods instead of OpenAL calls
+            float3 pos = source.GetPosition();  // Use your implemented accessor
+
+            // Draw a wireframe sphere at the sound source position
+            float color[4] = {1.0f, 0.0f, 0.0f, 0.7f}; // Red with some transparency
+            CMatrix44f matrix;
+            matrix.Translate(pos.x, pos.y, pos.z);
+            matrix.Scale(CSoundSource::REFERENCE_DIST * ELMOS_TO_METERS); // Adjusted scale for better visibility
+            GL::shapes.DrawWireSphere(8, 8, matrix, color);
+        }
+    }
+}
+

rts/System/Sound/OpenAL/Sound.h

@@ -10,6 +10,7 @@
 #include <alc.h>
 #include <SDL.h>
 
+#include "System/Sound/AttenuationModels/RtsAttenuationModel.h"
 #include "System/Sound/ISound.h"
 #include "System/float3.h"
 #include "System/UnorderedMap.hpp"
@@ -25,6 +26,8 @@ class SoundItem;
 /// Default sound system implementation (OpenAL)
 class CSound : public ISound
 {
+public:
+	void DrawDebug() const;  // Debug visualization method
 public:
 	CSound();
 	~CSound();
@@ -73,6 +76,9 @@ class CSound : public ISound
 	int GetFrameSize() const { return frameSize; }
 
 	std::vector<std::string> GetSoundDevices() override;
+
+    ISoundAttenuationModel* GetAttenuationModel() override { return attenuationModel; }
+
 private:
 	typedef spring::unordered_map<std::string, std::string> SoundItemNameMap;
 	typedef spring::unordered_map<std::string, SoundItemNameMap> SoundItemDefsMap;
@@ -103,6 +109,8 @@ class CSound : public ISound
 
 	std::string selectedDeviceName = "";
 
+    ISoundAttenuationModel* attenuationModel = nullptr;
+
 	spring::thread soundThread;
 	spring::unordered_map<std::string, size_t> soundMap; // <name, id>
 	spring::unordered_set<std::string> preloadSet;