water ripples (experimental)

apps/openmw/CMakeLists.txt

@@ -16,7 +16,7 @@ source_group(game FILES ${GAME} ${GAME_HEADER})
 add_openmw_dir (mwrender
     renderingmanager debugging sky player animation npcanimation creatureanimation actors objects
     renderinginterface localmap occlusionquery terrain terrainmaterial water shadows
-    compositors characterpreview externalrendering globalmap videoplayer
+    compositors characterpreview externalrendering globalmap videoplayer ripplesimulation
     )
 
 add_openmw_dir (mwinput

apps/openmw/mwrender/renderingmanager.cpp

@@ -386,7 +386,10 @@ void RenderingManager::update (float duration, bool paused)
                 *world->getPlayer().getPlayer().getCell()->mCell,
                 Ogre::Vector3(cam.x, -cam.z, cam.y))
         );
-        mWater->update(duration);
+
+        // MW to ogre coordinates
+        orig = Ogre::Vector3(orig.x, orig.z, -orig.y);
+        mWater->update(duration, orig);
     }
 }
 

apps/openmw/mwrender/ripplesimulation.cpp

@@ -0,0 +1,212 @@
+#include "ripplesimulation.hpp"
+
+#include <OgreTextureManager.h>
+#include <OgreStringConverter.h>
+#include <OgreHardwarePixelBuffer.h>
+#include <OgreRoot.h>
+
+#include <extern/shiny/Main/Factory.hpp>
+
+namespace MWRender
+{
+
+
+RippleSimulation::RippleSimulation(Ogre::SceneManager* mainSceneManager)
+    : mMainSceneMgr(mainSceneManager),
+      mTime(0),
+      mCurrentFrameOffset(0,0),
+      mPreviousFrameOffset(0,0),
+      mRippleCenter(0,0),
+      mTextureSize(512),
+      mRippleAreaLength(1000),
+      mImpulseSize(20),
+      mTexelOffset(0,0)
+{
+    Ogre::AxisAlignedBox aabInf;
+    aabInf.setInfinite();
+
+
+    mHeightToNormalMapMaterial = Ogre::MaterialManager::getSingleton().getByName("HeightToNormalMap");
+    mHeightmapMaterial = Ogre::MaterialManager::getSingleton().getByName("HeightmapSimulation");
+
+    mSceneMgr = Ogre::Root::getSingleton().createSceneManager(Ogre::ST_GENERIC);
+
+    mCamera = mSceneMgr->createCamera("RippleCamera");
+
+    mRectangle = new Ogre::Rectangle2D(true);
+    mRectangle->setBoundingBox(aabInf);
+    mRectangle->setCorners(-1.0, 1.0, 1.0, -1.0, false);
+    Ogre::SceneNode* node = mSceneMgr->getRootSceneNode()->createChildSceneNode();
+    node->attachObject(mRectangle);
+
+    mImpulse = new Ogre::Rectangle2D(true);
+    mImpulse->setCorners(-0.1, 0.1, 0.1, -0.1, false);
+    mImpulse->setBoundingBox(aabInf);
+    mImpulse->setMaterial("AddImpulse");
+    Ogre::SceneNode* impulseNode = mSceneMgr->getRootSceneNode()->createChildSceneNode();
+    impulseNode->attachObject(mImpulse);
+
+    float w=0.05;
+    for (int i=0; i<4; ++i)
+    {
+        Ogre::TexturePtr texture;
+        if (i != 3)
+            texture = Ogre::TextureManager::getSingleton().createManual("RippleHeight" + Ogre::StringConverter::toString(i),
+                Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, Ogre::TEX_TYPE_2D, mTextureSize, mTextureSize, 1, 0, Ogre::PF_R8G8B8, Ogre::TU_RENDERTARGET);
+        else
+            texture = Ogre::TextureManager::getSingleton().createManual("RippleNormal",
+                Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, Ogre::TEX_TYPE_2D, mTextureSize, mTextureSize, 1, 0, Ogre::PF_R8G8B8, Ogre::TU_RENDERTARGET);
+
+
+        Ogre::RenderTexture* rt = texture->getBuffer()->getRenderTarget();
+        rt->removeAllViewports();
+        rt->addViewport(mCamera);
+        rt->setAutoUpdated(false);
+        rt->getViewport(0)->setClearEveryFrame(false);
+
+        // debug overlay
+        Ogre::Rectangle2D* debugOverlay = new Ogre::Rectangle2D(true);
+        debugOverlay->setCorners(w*2-1, 0.9, (w+0.18)*2-1, 0.4, false);
+        w += 0.2;
+        debugOverlay->setBoundingBox(aabInf);
+
+        Ogre::SceneNode* debugNode = mMainSceneMgr->getRootSceneNode()->createChildSceneNode();
+        debugNode->attachObject(debugOverlay);
+
+        Ogre::MaterialPtr debugMaterial = Ogre::MaterialManager::getSingleton().create("RippleDebug" + Ogre::StringConverter::toString(i),
+            Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
+
+        if (i != 3)
+            debugMaterial->getTechnique(0)->getPass(0)->createTextureUnitState("RippleHeight" + Ogre::StringConverter::toString(i));
+        else
+            debugMaterial->getTechnique(0)->getPass(0)->createTextureUnitState("RippleNormal");
+        debugMaterial->getTechnique(0)->getPass(0)->setLightingEnabled(false);
+
+        debugOverlay->setMaterial("RippleDebug" + Ogre::StringConverter::toString(i));
+
+        mRenderTargets[i] = rt;
+        mTextures[i] = texture;
+    }
+
+    sh::Factory::getInstance().setSharedParameter("rippleTextureSize", sh::makeProperty<sh::Vector4>(
+        new sh::Vector4(1.0/512, 1.0/512, 512, 512)));
+    sh::Factory::getInstance().setSharedParameter("rippleCenter", sh::makeProperty<sh::Vector3>(
+         new sh::Vector3(0, 0, 0)));
+    sh::Factory::getInstance().setSharedParameter("rippleAreaLength", sh::makeProperty<sh::FloatValue>(
+         new sh::FloatValue(mRippleAreaLength)));
+
+}
+
+RippleSimulation::~RippleSimulation()
+{
+    delete mRectangle;
+
+    Ogre::Root::getSingleton().destroySceneManager(mSceneMgr);
+}
+
+void RippleSimulation::update(float dt, Ogre::Vector2 position)
+{
+    // try to keep 20 fps
+    mTime += dt;
+
+    while (mTime >= 1/20.0)
+    {
+        mPreviousFrameOffset = mCurrentFrameOffset;
+
+        mCurrentFrameOffset = position - mRippleCenter;
+        // add texel offsets from previous frame.
+        mCurrentFrameOffset += mTexelOffset;
+
+        mTexelOffset = Ogre::Vector2(std::fmod(mCurrentFrameOffset.x, 1.0f/mTextureSize),
+                                          std::fmod(mCurrentFrameOffset.y, 1.0f/mTextureSize));
+
+        // now subtract new offset in order to snap to texels
+        mCurrentFrameOffset -= mTexelOffset;
+
+        // texture coordinate space
+        mCurrentFrameOffset /= mRippleAreaLength;
+
+        std::cout << "Offset " << mCurrentFrameOffset << std::endl;
+
+        mRippleCenter = position;
+
+        addImpulses();
+        waterSimulation();
+        heightMapToNormalMap();
+
+        swapHeightMaps();
+        mTime -= 1/20.0;
+    }
+
+    sh::Factory::getInstance().setSharedParameter("rippleCenter", sh::makeProperty<sh::Vector3>(
+         new sh::Vector3(mRippleCenter.x + mTexelOffset.x, mRippleCenter.y + mTexelOffset.y, 0)));
+}
+
+void RippleSimulation::addImpulse(Ogre::Vector2 position)
+{
+    mImpulses.push(position);
+}
+
+void RippleSimulation::addImpulses()
+{
+    mRectangle->setVisible(false);
+    mImpulse->setVisible(true);
+
+    while (mImpulses.size())
+    {
+        Ogre::Vector2 pos = mImpulses.front();
+        pos -= mRippleCenter;
+        pos /= mRippleAreaLength;
+        float size = mImpulseSize / mRippleAreaLength;
+        mImpulse->setCorners(pos.x-size, pos.y+size, pos.x+size, pos.y-size, false);
+        mImpulses.pop();
+
+        mRenderTargets[1]->update();
+    }
+
+    mImpulse->setVisible(false);
+    mRectangle->setVisible(true);
+}
+
+void RippleSimulation::waterSimulation()
+{
+    mRectangle->setMaterial("HeightmapSimulation");
+
+    sh::Factory::getInstance().setTextureAlias("Heightmap0", mTextures[0]->getName());
+    sh::Factory::getInstance().setTextureAlias("Heightmap1", mTextures[1]->getName());
+
+    sh::Factory::getInstance().setSharedParameter("currentFrameOffset", sh::makeProperty<sh::Vector3>(
+        new sh::Vector3(mCurrentFrameOffset.x, mCurrentFrameOffset.y, 0)));
+    sh::Factory::getInstance().setSharedParameter("previousFrameOffset", sh::makeProperty<sh::Vector3>(
+        new sh::Vector3(mPreviousFrameOffset.x, mPreviousFrameOffset.y, 0)));
+
+    mRenderTargets[2]->update();
+}
+
+void RippleSimulation::heightMapToNormalMap()
+{
+    mRectangle->setMaterial("HeightToNormalMap");
+
+    sh::Factory::getInstance().setTextureAlias("Heightmap2", mTextures[2]->getName());
+
+    mRenderTargets[TEX_NORMAL]->update();
+}
+
+void RippleSimulation::swapHeightMaps()
+{
+    // 0 -> 1 -> 2 to 2 -> 0 ->1
+    Ogre::RenderTexture* tmp = mRenderTargets[0];
+    Ogre::TexturePtr tmp2 = mTextures[0];
+
+    mRenderTargets[0] = mRenderTargets[1];
+    mTextures[0] = mTextures[1];
+
+    mRenderTargets[1] = mRenderTargets[2];
+    mTextures[1] = mTextures[2];
+
+    mRenderTargets[2] = tmp;
+    mTextures[2] = tmp2;
+}
+
+
+}

apps/openmw/mwrender/ripplesimulation.hpp

@@ -0,0 +1,72 @@
+#ifndef RIPPLE_SIMULATION_H
+#define RIPPLE_SIMULATION_H
+
+#include <OgreTexture.h>
+#include <OgreMaterial.h>
+#include <OgreVector2.h>
+
+namespace Ogre
+{
+    class RenderTexture;
+    class Camera;
+    class SceneManager;
+    class Rectangle2D;
+}
+
+namespace MWRender
+{
+
+class RippleSimulation
+{
+public:
+    RippleSimulation(Ogre::SceneManager* mainSceneManager);
+    ~RippleSimulation();
+
+    void update(float dt, Ogre::Vector2 position);
+
+    void addImpulse (Ogre::Vector2 position);
+
+private:
+    Ogre::RenderTexture* mRenderTargets[4];
+    Ogre::TexturePtr mTextures[4];
+
+    int mTextureSize;
+    float mRippleAreaLength;
+    float mImpulseSize;
+
+    Ogre::Camera* mCamera;
+
+    // own scenemanager to render our simulation
+    Ogre::SceneManager* mSceneMgr;
+    Ogre::Rectangle2D* mRectangle;
+
+    // scenemanager to create the debug overlays on
+    Ogre::SceneManager* mMainSceneMgr;
+
+    Ogre::MaterialPtr mHeightmapMaterial;
+    Ogre::MaterialPtr mHeightToNormalMapMaterial;
+
+    static const int TEX_NORMAL = 3;
+
+    Ogre::Rectangle2D* mImpulse;
+
+    std::queue <Ogre::Vector2> mImpulses;
+
+    void addImpulses();
+    void heightMapToNormalMap();
+    void waterSimulation();
+    void swapHeightMaps();
+
+    float mTime;
+
+    Ogre::Vector2 mRippleCenter;
+
+    Ogre::Vector2 mTexelOffset;
+
+    Ogre::Vector2 mCurrentFrameOffset;
+    Ogre::Vector2 mPreviousFrameOffset;
+};
+
+}
+
+#endif

apps/openmw/mwrender/water.cpp

@@ -12,6 +12,7 @@
 #include "sky.hpp"
 #include "renderingmanager.hpp"
 #include "compositors.hpp"
+#include "ripplesimulation.hpp"
 
 #include <extern/shiny/Main/Factory.hpp>
 #include <extern/shiny/Platforms/Ogre/OgreMaterial.hpp>
@@ -180,8 +181,11 @@ Water::Water (Ogre::Camera *camera, RenderingManager* rend, const ESM::Cell* cel
     mActive(1), mToggled(1),
     mRendering(rend),
     mWaterTimer(0.f),
-    mReflection(NULL)
+    mReflection(NULL),
+    mSimulation(NULL)
 {
+    mSimulation = new RippleSimulation(mSceneMgr);
+
     mSky = rend->getSkyManager();
 
     mMaterial = MaterialManager::getSingleton().getByName("Water");
@@ -375,7 +379,7 @@ void Water::updateVisible()
     }
 }
 
-void Water::update(float dt)
+void Water::update(float dt, Ogre::Vector3 player)
 {
     /*
     Ogre::Vector3 pos = mCamera->getDerivedPosition ();
@@ -387,6 +391,12 @@ void Water::update(float dt)
     sh::Factory::getInstance ().setSharedParameter ("waterTimer", sh::makeProperty<sh::FloatValue>(new sh::FloatValue(mWaterTimer)));
 
     mRendering->getSkyManager ()->setGlareEnabled (!mIsUnderwater);
+
+    //if (player.y <= mTop)
+    {
+        mSimulation->addImpulse(Ogre::Vector2(player.x, player.z));
+    }
+    mSimulation->update(dt, Ogre::Vector2(player.x, player.z));
 }
 
 void Water::applyRTT()

apps/openmw/mwrender/water.hpp

@@ -29,6 +29,7 @@ namespace MWRender {
 
     class SkyManager;
     class RenderingManager;
+    class RippleSimulation;
 
     class Reflection
     {
@@ -110,6 +111,8 @@ namespace MWRender {
 
         float mWaterTimer;
 
+        RippleSimulation* mSimulation;
+
         Ogre::Vector3 getSceneNodeCoordinates(int gridX, int gridY);
 
     protected:
@@ -137,7 +140,7 @@ namespace MWRender {
         void setActive(bool active);
 
         void toggle();
-        void update(float dt);
+        void update(float dt, Ogre::Vector3 player);
 
         void assignTextures();
 

extern/shiny/Main/Factory.cpp

@@ -219,6 +219,8 @@ namespace sh
 					break;
 				}
 
+                std::cout << "loading " << it->first << std::endl;
+
 				MaterialInstance newInstance(it->first, this);
 				newInstance.create(mPlatform);
 				if (!mShadersEnabled)

files/CMakeLists.txt

@@ -3,6 +3,7 @@ project(resources)
 set(WATER_FILES
     underwater_dome.mesh
     water_nm.png
+    circle.png
 )
 
 set(GBUFFER_FILES
@@ -43,6 +44,12 @@ set(MATERIAL_FILES
     selection.mat
     selection.shader
     selection.shaderset
+    watersim_heightmap.shader
+    watersim_addimpulse.shader
+    watersim_heighttonormal.shader
+    watersim_common.h
+    watersim.mat
+    watersim.shaderset
 )
 
 copy_all_files(${CMAKE_CURRENT_SOURCE_DIR}/water "${OpenMW_BINARY_DIR}/resources/water/" "${WATER_FILES}")

files/materials/core.h

@@ -28,6 +28,8 @@
     #define shNormalInput(type) , in type normal : NORMAL
     
     #define shColourInput(type) , in type colour : COLOR
+    
+    #define shFract(val) frac(val)
 
     #ifdef SH_VERTEX_SHADER
 
@@ -64,6 +66,8 @@
 
 #if SH_GLSL == 1
 
+	#define shFract(val) fract(val)
+
     @version 120
 
     #define float2 vec2

files/materials/quad.mat

@@ -4,7 +4,7 @@ material quad
     
     pass
     {
-        vertex_program quad_vertex
+        vertex_program transform_vertex
         fragment_program quad_fragment
         
         depth_write $depth_write

files/materials/quad.shaderset

@@ -1,4 +1,4 @@
-shader_set quad_vertex
+shader_set transform_vertex
 {
     source quad.shader
     type vertex

files/materials/water.mat

@@ -34,7 +34,13 @@ material Water
         {
             direct_texture water_nm.png
         }
-        
+
+        texture_unit rippleNormalMap
+        {
+            direct_texture RippleNormal
+            tex_address_mode border
+            tex_border_colour 0.5 0.5 1.0
+        }
         
         // for simple_water
         texture_unit animatedTexture

files/materials/water.shader

@@ -61,7 +61,7 @@
 
 // Inspired by Blender GLSL Water by martinsh ( http://devlog-martinsh.blogspot.de/2012/07/waterundewater-shader-wip.html )
 
-
+#define RIPPLES 1
 
 #ifdef SH_VERTEX_SHADER
 
@@ -119,8 +119,8 @@
         #define WAVE_SCALE 75                      // overall wave scale
 
         #define BUMP 1.5                            // overall water surface bumpiness
-        #define REFL_BUMP 0.08                      // reflection distortion amount
+        #define REFL_BUMP 0.16                      // reflection distortion amount
-        #define REFR_BUMP 0.06                      // refraction distortion amount
+        #define REFR_BUMP 0.12                      // refraction distortion amount
 
         #define SCATTER_AMOUNT 3.0                  // amount of sunlight scattering
         #define SCATTER_COLOUR gammaCorrectRead(float3(0.0,1.0,0.95)) // colour of sunlight scattering
@@ -159,6 +159,11 @@
 		shInput(float3, screenCoordsPassthrough)
 		shInput(float4, position)
 		shInput(float, depthPassthrough)
+
+            #if RIPPLES
+                shUniform(float3, rippleCenter) @shSharedParameter(rippleCenter, rippleCenter)
+                shUniform(float, rippleAreaLength) @shSharedParameter(rippleAreaLength, rippleAreaLength)
+            #endif
 		
 		shUniform(float, far) @shAutoConstant(far, far_clip_distance)
 	
@@ -166,6 +171,11 @@
 		shSampler2D(refractionMap)
 		shSampler2D(depthMap)
 		shSampler2D(normalMap)
+
+            #if RIPPLES
+                shSampler2D(rippleNormalMap)
+                shUniform(float4x4, wMat) @shAutoConstant(wMat, world_matrix)
+            #endif
 		
 		shUniform(float3, windDir_windSpeed) @shSharedParameter(windDir_windSpeed)
 		#define WIND_SPEED windDir_windSpeed.z
@@ -220,8 +230,14 @@
 	    float3 normal = (normal0 * BIG_WAVES_X + normal1 * BIG_WAVES_Y +
                                 normal2 * MID_WAVES_X + normal3 * MID_WAVES_Y +
 						        normal4 * SMALL_WAVES_X + normal5 * SMALL_WAVES_Y).xzy;
-        
+
-        normal = normalize(float3(normal.x * BUMP, normal.y, normal.z * BUMP));
+        float4 worldPosition = shMatrixMult(wMat, float4(position.xyz, 1));
+        float2 relPos = (worldPosition.xz - rippleCenter.xy) / rippleAreaLength + 0.5;
+        float3 normal_ripple = normalize(shSample(rippleNormalMap, relPos.xy).xyz * 2 - 1);
+        normal_ripple = normal_ripple.xzy;
+
+        normal = normalize(normal + normal_ripple);
+
 	    
 	    // normal for sunlight scattering			        
 		float3 lNormal = (normal0 * BIG_WAVES_X*0.5 + normal1 * BIG_WAVES_Y*0.5 +
@@ -303,7 +319,7 @@
         }
 
         shOutputColour(0).xyz = gammaCorrectOutput(shOutputColour(0).xyz);
-
+        //shOutputColour(0).xyz = float3(relPos.x, relPos.y, 0);
 		shOutputColour(0).w = 1;
     }
 

files/materials/watersim.mat

@@ -0,0 +1,59 @@
+material HeightmapSimulation
+{
+	allow_fixed_function false
+	pass
+	{
+		depth_check off
+		depth_write off
+		vertex_program transform_vertex
+		fragment_program watersim_fragment
+
+                texture_unit heightPrevSampler
+		{
+			tex_address_mode border
+			tex_border_colour 0 0 0
+			texture_alias Heightmap0
+		}
+                texture_unit heightCurrentSampler
+		{
+			tex_address_mode border
+			tex_border_colour 0 0 0
+			texture_alias Heightmap1
+		}
+	}
+}
+
+material HeightToNormalMap
+{
+        allow_fixed_function false
+	pass
+	{
+		depth_check off
+		depth_write off
+		vertex_program transform_vertex
+		fragment_program height_to_normal_fragment
+		
+                texture_unit heightCurrentSampler
+		{
+			texture_alias Heightmap2
+		}
+	}
+}
+
+material AddImpulse
+{
+        allow_fixed_function false
+        pass
+        {
+                depth_check off
+                depth_write off
+                scene_blend alpha_blend
+                vertex_program transform_vertex
+                fragment_program add_impulse_fragment
+
+                texture_unit alphaMap
+                {
+                        texture circle.png
+                }
+        }
+}

files/materials/watersim.shaderset

@@ -0,0 +1,31 @@
+shader_set transform_vertex
+{
+    source quad.shader
+    type vertex
+    profiles_cg vs_2_0 vp40 arbvp1
+    profiles_hlsl vs_2_0
+}
+
+shader_set watersim_fragment
+{
+	source watersim_heightmap.shader
+	type fragment
+	profiles_cg ps_3_0 ps_2_x ps_2_0 fp40 arbfp1
+	profiles_hlsl ps_3_0 ps_2_0
+}
+
+shader_set height_to_normal_fragment
+{
+	source watersim_heighttonormal.shader
+	type fragment
+	profiles_cg ps_3_0 ps_2_x ps_2_0 fp40 arbfp1
+	profiles_hlsl ps_3_0 ps_2_0
+}
+
+shader_set add_impulse_fragment
+{
+	source watersim_addimpulse.shader
+	type fragment
+	profiles_cg ps_3_0 ps_2_x ps_2_0 fp40 arbfp1
+	profiles_hlsl ps_3_0 ps_2_0
+}

files/materials/watersim_addimpulse.shader

@@ -0,0 +1,12 @@
+#include "core.h"
+#include "watersim_common.h"
+
+    SH_BEGIN_PROGRAM
+        shInput(float2, UV)
+        shSampler2D(alphaMap)
+
+    SH_START_PROGRAM
+    {
+		shOutputColour(0) = EncodeHeightmap(1.0);
+		shOutputColour(0).a = shSample (alphaMap, UV.xy).a;
+    }

files/materials/watersim_common.h

@@ -0,0 +1,25 @@
+float DecodeHeightmap(float4 heightmap)
+{
+    float4 table = float4(1.0, -1.0, 0.0, 0.0);
+	return dot(heightmap, table);
+}
+
+float DecodeHeightmap(shTexture2D HeightmapSampler, float2 texcoord)
+{
+	float4 heightmap = shSample(HeightmapSampler, texcoord);
+	return DecodeHeightmap(heightmap);
+}
+
+float4 EncodeHeightmap(float fHeight)
+{
+	float h = fHeight;
+	float positive = fHeight > 0.0 ? fHeight : 0.0;
+	float negative = fHeight < 0.0 ? -fHeight : 0.0;
+
+	float4 color = float4(0,0,0,0);
+
+	color.r = positive;
+	color.g = negative;
+
+	return color;
+}

files/materials/watersim_heightmap.shader

@@ -0,0 +1,42 @@
+#include "core.h"
+
+#define DAMPING 0.92
+
+#include "watersim_common.h"
+
+    SH_BEGIN_PROGRAM
+        shInput(float2, UV)
+        shSampler2D(heightPrevSampler)
+        shSampler2D(heightCurrentSampler)
+        shUniform(float3, previousFrameOffset) @shSharedParameter(previousFrameOffset, previousFrameOffset)
+        shUniform(float3, currentFrameOffset) @shSharedParameter(currentFrameOffset, currentFrameOffset)
+        shUniform(float4, rippleTextureSize) @shSharedParameter(rippleTextureSize, rippleTextureSize)
+
+    SH_START_PROGRAM
+    {
+		const float3 offset[4] = float3[4](
+			float3(-1.0, 0.0, 0.25),
+			float3( 1.0, 0.0, 0.25),
+			float3( 0.0,-1.0, 0.25),
+			float3( 0.0, 1.0, 0.25)
+		);	
+
+                float fHeightPrev = DecodeHeightmap(heightPrevSampler, UV.xy + previousFrameOffset.xy + currentFrameOffset.xy);
+		
+		float fNeighCurrent = 0;
+		for ( int i=0; i<4; i++ )
+		{
+                        float2 vTexcoord = UV + currentFrameOffset.xy + offset[i].xy * rippleTextureSize.xy;
+			fNeighCurrent += (DecodeHeightmap(heightCurrentSampler, vTexcoord) * offset[i].z);
+		}
+		
+		float fHeight = fNeighCurrent * 2.0 - fHeightPrev;
+		
+		fHeight *= DAMPING;
+		
+		shOutputColour(0) = EncodeHeightmap(fHeight);
+    }
+    
+    
+    
+    

files/materials/watersim_heighttonormal.shader

@@ -0,0 +1,27 @@
+#include "core.h"
+#include "watersim_common.h"
+
+    SH_BEGIN_PROGRAM
+        shInput(float2, UV)
+        shSampler2D(heightCurrentSampler)
+        shUniform(float4, rippleTextureSize) @shSharedParameter(rippleTextureSize, rippleTextureSize)
+
+    SH_START_PROGRAM
+    {
+		float2 offset[4] = float2[4] (
+			vec2(-1.0, 0.0),
+			vec2( 1.0, 0.0),
+			vec2( 0.0,-1.0),
+			vec2( 0.0, 1.0)
+		);
+
+		float fHeightL = DecodeHeightmap(heightCurrentSampler, UV.xy + offset[0]*rippleTextureSize.xy);
+		float fHeightR = DecodeHeightmap(heightCurrentSampler, UV.xy + offset[1]*rippleTextureSize.xy);
+		float fHeightT = DecodeHeightmap(heightCurrentSampler, UV.xy + offset[2]*rippleTextureSize.xy);
+		float fHeightB = DecodeHeightmap(heightCurrentSampler, UV.xy + offset[3]*rippleTextureSize.xy);
+		
+		float3 n = float3(fHeightB - fHeightT, fHeightR - fHeightL, 1.0);
+		float3 normal = (n + 1.0) * 0.5;
+		
+		shOutputColour(0) = float4(normal.rgb, 1.0);
+    }