GeometryBlock.cpp

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/*
--------------------------------------------------------------------------------
This source file is part of SkyX.
Visit http://www.paradise-studios.net/products/skyx/
 
Copyright (C) 2009-2012 Xavier Verguín González <xavyiy@gmail.com>
 
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
 
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 
You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
--------------------------------------------------------------------------------
*/
 
#include "GeometryBlock.h"
 
#include "VClouds.h"
 
namespace SkyX { namespace VClouds
{
    GeometryBlock::GeometryBlock(VClouds* vc,
            const float& Height, const Ogre::Radian& Alpha, const Ogre::Radian& Beta, 
            const float& Radius, const Ogre::Radian& Phi, const int& Na, 
            const int& Nb, const int& Nc, const int& A, 
            const int& B, const int& C, const int& Position)
        : mVClouds(vc)
        , mCreated(false)
        , mSubMesh(0)
        , mEntity(0)
        , mVertices(0)
        , mNumberOfTriangles(0)
        , mVertexCount(0)
        , mHeight(Height)
        , mAlpha(Alpha)
        , mBeta(Beta)
        , mRadius(Radius)
        , mPhi(Phi)
        , mNa(Na) , mNb(Nb) , mNc(Nc)
        , mA(A) , mB(B) , mC(C)
        , mPosition(Position)
        , mDisplacement(Ogre::Vector3(0,0,0))
        , mWorldOffset(Ogre::Vector2(0,0))
        , mCamera(0)
        , mDistance(Ogre::Vector3(0,0,0))
        , mLastFallingDistance(0)
    {
        _calculateDataSize();
    }
 
    GeometryBlock::~GeometryBlock()
    {
        remove();
    }
 
    void GeometryBlock::create()
    {
        remove();
 
        // Create mesh and submesh
        mMesh = Ogre::MeshManager::getSingleton().createManual("_SkyX_VClouds_Block" + Ogre::StringConverter::toString(mPosition),
            Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
        mSubMesh = mMesh->createSubMesh();
        mSubMesh->useSharedVertices = false;
 
        // Create mesh geometry
        _createGeometry();
 
        // Build edge list
        mMesh->buildEdgeList();
 
        // End mesh creation
        mMesh->load();
        mMesh->touch();
 
        // Create entity
        mEntity = mVClouds->getSceneManager()->createEntity("_SkyX_VClouds_BlockEnt" + Ogre::StringConverter::toString(mPosition), "_SkyX_VClouds_Block" + Ogre::StringConverter::toString(mPosition));
        mEntity->setMaterialName("SkyX_VolClouds");
        mEntity->setCastShadows(false);
        mEntity->setRenderQueueGroup(mVClouds->getRenderQueueGroups().vclouds);
 
        // Set bounds
        mMesh->_setBounds(_buildAABox(mLastFallingDistance));
 
        mCreated = true;
    }
 
    void GeometryBlock::remove()
    {
        if (!mCreated)
        {
            return;
        }
 
        Ogre::MeshManager::getSingleton().remove(mMesh->getName());
        mVClouds->getSceneManager()->destroyEntity(mEntity);
 
        mMesh.setNull();
        mSubMesh = 0;
        mEntity = 0;
        mVertexBuffer.setNull();
        mIndexBuffer.setNull();
 
        delete [] mVertices;
 
        mCreated = false;
    }
 
    const Ogre::AxisAlignedBox GeometryBlock::_buildAABox(const float& fd) const
    {
        Ogre::Vector2 Center = Ogre::Vector2(0,0);
        Ogre::Vector2 V1     = mRadius*Ogre::Vector2(Ogre::Math::Cos(mPhi*mPosition), Ogre::Math::Sin(mPhi*mPosition));
        Ogre::Vector2 V2     = mRadius*Ogre::Vector2(Ogre::Math::Cos(mPhi*(mPosition+1)), Ogre::Math::Sin(mPhi*(mPosition+1)));
 
        Ogre::Vector2 Max    = Ogre::Vector2(std::max<float>(std::max<float>(V1.x, V2.x), Center.x), std::max<float>(std::max<float>(V1.y, V2.y), Center.y) );
        Ogre::Vector2 Min    = Ogre::Vector2(std::min<float>(std::min<float>(V1.x, V2.x), Center.x), std::min<float>(std::min<float>(V1.y, V2.y), Center.y) );
 
        return Ogre::AxisAlignedBox(
                              // Min x,y,z
                              Min.x, -std::max<float>(fd,0),          Min.y,
                              // Max x,y,z
                              Max.x, mHeight - std::min<float>(fd,0), Max.y);
    }
 
    void GeometryBlock::_calculateDataSize()
    {
        mVertexCount = 7*mNa + 6*mNb + 4*mNc;
        mNumberOfTriangles = 5*mNa + 4*mNb + 2*mNc;
 
        mV2Cos = Ogre::Vector2(Ogre::Math::Cos(mPosition*mPhi), Ogre::Math::Cos((mPosition+1)*mPhi));
        mV2Sin = Ogre::Vector2(Ogre::Math::Sin(mPosition*mPhi), Ogre::Math::Sin((mPosition+1)*mPhi));
 
        mBetaSin  = Ogre::Math::Sin(Ogre::Math::PI-mBeta.valueRadians());
        mAlphaSin = Ogre::Math::Sin(Ogre::Math::PI-mAlpha.valueRadians());
    }
 
    void GeometryBlock::_createGeometry()
    {
        // Vertex buffers
        mSubMesh->vertexData = new Ogre::VertexData();
        mSubMesh->vertexData->vertexStart = 0;
        mSubMesh->vertexData->vertexCount = mVertexCount;
 
        Ogre::VertexDeclaration* vdecl = mSubMesh->vertexData->vertexDeclaration;
        Ogre::VertexBufferBinding* vbind = mSubMesh->vertexData->vertexBufferBinding;
 
        size_t offset = 0;
        // Position
        vdecl->addElement(0, offset, Ogre::VET_FLOAT3, Ogre::VES_POSITION);
        offset += Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT3);
        // 3D coords
        vdecl->addElement(0, offset, Ogre::VET_FLOAT3, Ogre::VES_TEXTURE_COORDINATES, 0);
        offset += Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT3);
        // Noise coords
        vdecl->addElement(0, offset, Ogre::VET_FLOAT2, Ogre::VES_TEXTURE_COORDINATES, 1);
        offset += Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT2);
        // Opacity
        vdecl->addElement(0, offset, Ogre::VET_FLOAT1, Ogre::VES_TEXTURE_COORDINATES, 2);
 
        mVertexBuffer = Ogre::HardwareBufferManager::getSingleton().
            createVertexBuffer(sizeof(VERTEX),
                               mVertexCount,
                               Ogre::HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY);
 
        vbind->setBinding(0, mVertexBuffer);
 
        unsigned short *indexbuffer = new unsigned short[mNumberOfTriangles*3];
 
        int IndexOffset = 0;
        int VertexOffset = 0;
 
        // C
        for (int k = 0; k < mNc; k++)
        {
            // First triangle
            indexbuffer[IndexOffset]   = VertexOffset;
            indexbuffer[IndexOffset+1] = VertexOffset+1;
            indexbuffer[IndexOffset+2] = VertexOffset+3;
 
            // Second triangle
            indexbuffer[IndexOffset+3] = VertexOffset;
            indexbuffer[IndexOffset+4] = VertexOffset+3;
            indexbuffer[IndexOffset+5] = VertexOffset+2;
 
            IndexOffset  += 6;
            VertexOffset += 4;
        }
 
        // B
        for (int k = 0; k < mNb; k++)
        {
            // First triangle
            indexbuffer[IndexOffset]   = VertexOffset;
            indexbuffer[IndexOffset+1] = VertexOffset+1;
            indexbuffer[IndexOffset+2] = VertexOffset+3;
 
            // Second triangle
            indexbuffer[IndexOffset+3] = VertexOffset;
            indexbuffer[IndexOffset+4] = VertexOffset+3;
            indexbuffer[IndexOffset+5] = VertexOffset+2;
 
            // Third triangle
            indexbuffer[IndexOffset+6] = VertexOffset+2;
            indexbuffer[IndexOffset+7] = VertexOffset+3;
            indexbuffer[IndexOffset+8] = VertexOffset+5;
 
            // Fourth triangle
            indexbuffer[IndexOffset+9] = VertexOffset+2;
            indexbuffer[IndexOffset+10] = VertexOffset+5;
            indexbuffer[IndexOffset+11] = VertexOffset+4;
 
            IndexOffset  += 12;
            VertexOffset += 6;
        }
 
        // A
        for (int k = 0; k < mNa; k++)
        {
            // First triangle
            indexbuffer[IndexOffset]   = VertexOffset;
            indexbuffer[IndexOffset+1] = VertexOffset+1;
            indexbuffer[IndexOffset+2] = VertexOffset+3;
 
            // Second triangle
            indexbuffer[IndexOffset+3] = VertexOffset;
            indexbuffer[IndexOffset+4] = VertexOffset+3;
            indexbuffer[IndexOffset+5] = VertexOffset+2;
 
            // Third triangle
            indexbuffer[IndexOffset+6]   = VertexOffset+2;
            indexbuffer[IndexOffset+7] = VertexOffset+3;
            indexbuffer[IndexOffset+8] = VertexOffset+5;
 
            // Fourth triangle
            indexbuffer[IndexOffset+9] = VertexOffset+2;
            indexbuffer[IndexOffset+10] = VertexOffset+5;
            indexbuffer[IndexOffset+11] = VertexOffset+4;
 
            // Fifth triangle
            indexbuffer[IndexOffset+12] = VertexOffset+4;
            indexbuffer[IndexOffset+13] = VertexOffset+5;
            indexbuffer[IndexOffset+14] = VertexOffset+6;
 
            IndexOffset  += 15;
            VertexOffset += 7;
        }
 
        // Prepare buffer for indices
        mIndexBuffer =
            Ogre::HardwareBufferManager::getSingleton().createIndexBuffer(
            Ogre::HardwareIndexBuffer::IT_16BIT,
            mNumberOfTriangles*3,
            Ogre::HardwareBuffer::HBU_STATIC, true);
 
        mIndexBuffer->
            writeData(0,
                      mIndexBuffer->getSizeInBytes(),
                      indexbuffer,
                      true);
 
        delete []indexbuffer;
 
        // Set index buffer for this submesh
        mSubMesh->indexData->indexBuffer = mIndexBuffer;
        mSubMesh->indexData->indexStart = 0;
        mSubMesh->indexData->indexCount = mNumberOfTriangles*3;
 
        // Create our internal buffer for manipulations
        mVertices = new VERTEX[mVertexCount];
    }
 
    void GeometryBlock::updateGeometry(Ogre::Camera* c, const Ogre::Vector3& displacement, const Ogre::Vector3& distance)
    {
        if (!mCreated)
        {
            return;
        }
 
        mDisplacement = displacement;
 
        float fallingDistance = mVClouds->getDistanceFallingParams().x*(mEntity->getParentSceneNode()->_getDerivedPosition().y-c->getDerivedPosition().y);
 
        if (mVClouds->getDistanceFallingParams().y > 0) // -1 means no max falling
        {
            if (fallingDistance > 0)
            {
                if (fallingDistance > mVClouds->getDistanceFallingParams().y)
                {
                    fallingDistance = mVClouds->getDistanceFallingParams().y;
                }
            }
            else
            {
                if (-fallingDistance > mVClouds->getDistanceFallingParams().y)
                {
                    fallingDistance = -mVClouds->getDistanceFallingParams().y;
                }
            }
        }
 
        if (fallingDistance != mLastFallingDistance)
        {
            mLastFallingDistance = fallingDistance;
            mMesh->_setBounds(_buildAABox(mLastFallingDistance));
        }
 
        if (isInFrustum(c))
        {
            mCamera = c;
            mDistance = distance;
            _updateGeometry();
        }
    }
 
    void GeometryBlock::_updateGeometry()
    {
        // Update zone C
        for (int k = 0; k < mNc; k++)
        {
            _updateZoneCSlice(k);
        }
 
        // Update zone B
        for (int k = 0; k < mNb; k++)
        {
            _updateZoneBSlice(k);
        }
 
        // Update zone A
        for (int k = 0; k < mNa; k++)
        {
            _updateZoneASlice(k);
        }
 
        // Upload changes
        mVertexBuffer->
                writeData(0,
                          mVertexBuffer->getSizeInBytes(),
                          mVertices,
                          true);
    }
 
    void GeometryBlock::_updateZoneCSlice(const int& n)
    {
        int VertexOffset = n*4;
 
        // TODO, calculate constants by zone, not by slice
        float Radius = mB+((mC-mB)/mNc)*(mNc-n);
 
        Radius += mDisplacement.z;
 
        float opacity = 1;
 
        if (n == 0)
        {
            opacity = 1 - mDisplacement.z/((mC-mB)/mNc);
        }
        else if (n == mNc-1)
        {
            opacity = mDisplacement.z/((mC-mB)/mNc);
        }
 
        Ogre::Vector2 x1 = Radius*mV2Cos,
                      x2 = Radius*mBetaSin*mV2Cos,
                      z1 = Radius*mV2Sin,
                      z2 = Radius*mBetaSin*mV2Sin;
        
        Ogre::Vector3 or0 = Ogre::Vector3(x1.x, 0, z1.x),
                      or1 = Ogre::Vector3(x1.y, 0, z1.y);
 
        float y0 = Radius*Ogre::Math::Sin(mAlpha),
               d = Ogre::Vector2(x1.x - x2.x, z1.x - z2.x).length(),
             ang = Ogre::Math::ATan(y0/d).valueRadians(),
             hip = mHeight / Ogre::Math::Sin(ang);
 
        // Vertex 0
        _setVertexData(VertexOffset, or0, opacity);
        // Vertex 1
        _setVertexData(VertexOffset+1, or1, opacity);
        // Vertex 2
        _setVertexData(VertexOffset+2, or0+(Ogre::Vector3(x2.x, y0, z2.x)-or0).normalisedCopy()*hip, opacity);
        // Vertex 3
        _setVertexData(VertexOffset+3, or1+(Ogre::Vector3(x2.y, y0, z2.y)-or1).normalisedCopy()*hip, opacity);
    }
 
    void GeometryBlock::_updateZoneBSlice(const int& n)
    {
        int VertexOffset = mNc*4 + n*6;
 
        // TODO
        float Radius = mA+((mB-mA)/mNb)*(mNb-n);
 
        Radius += mDisplacement.y;
 
        float opacity = 1;
 
        if (n == 0)
        {
            opacity = 1-mDisplacement.y/((mB-mA)/mNb);
        }
        else if (n == mNb-1)
        {
            opacity = mDisplacement.y/((mB-mA)/mNb);
        }
 
        Ogre::Vector2 x1 = Radius*mV2Cos,
                      x2 = Radius*mBetaSin*mV2Cos,
                      z1 = Radius*mV2Sin,
                      z2 = Radius*mBetaSin*mV2Sin;
        
        float y0 = Radius*Ogre::Math::Sin(mAlpha);
 
        // Vertex 0
        _setVertexData(VertexOffset, Ogre::Vector3(x1.x, 0, z1.x), opacity);
        // Vertex 1
        _setVertexData(VertexOffset+1, Ogre::Vector3(x1.y, 0, z1.y), opacity);
        // Vertex 2
        _setVertexData(VertexOffset+2, Ogre::Vector3(x2.x, y0, z2.x), opacity);
        // Vertex 3
        _setVertexData(VertexOffset+3, Ogre::Vector3(x2.y, y0, z2.y), opacity);
 
        Ogre::Vector2 x3 = Radius*mAlphaSin*mV2Cos,
                      z3 = Radius*mAlphaSin*mV2Sin;
 
        Ogre::Vector3 or0 = Ogre::Vector3(x2.x, y0, z2.x),
                      or1 = Ogre::Vector3(x2.y, y0, z2.y);
 
        float y1 = Radius*Ogre::Math::Sin(mBeta),
              y3 = y1-y0,
               d = Ogre::Vector2(x3.x - x2.x, z3.x - z2.x).length(),
             ang = Ogre::Math::ATan(y3/d).valueRadians(),
             hip = (mHeight-y0) / Ogre::Math::Sin(ang);
 
        // Vertex 4
        _setVertexData(VertexOffset+4, or0 + (Ogre::Vector3(x3.x, y1, z3.x)-or0).normalisedCopy()*hip, opacity);
        // Vertex 5
        _setVertexData(VertexOffset+5, or1 + (Ogre::Vector3(x3.y, y1, z3.y)-or1).normalisedCopy()*hip, opacity);
    }
 
    void GeometryBlock::_updateZoneASlice(const int& n)
    {
        int VertexOffset = mNc*4 + mNb*6 +n*7;
 
        // TODO
        float Radius = (mA/mNa)*(mNa-n);
 
        Radius += mDisplacement.x;
 
        float opacity = (n == 0) ? (1-mDisplacement.x/(mA/mNa)) : 1.0f;
 
        Ogre::Vector2 x1 = Radius*mV2Cos,
                      x2 = Radius*mBetaSin*mV2Cos,
                      z1 = Radius*mV2Sin,
                      z2 = Radius*mBetaSin*mV2Sin;
        
        float y0 = Radius*Ogre::Math::Sin(mAlpha);
 
        // Vertex 0
        _setVertexData(VertexOffset, Ogre::Vector3(x1.x, 0, z1.x), opacity);
        // Vertex 1
        _setVertexData(VertexOffset+1, Ogre::Vector3(x1.y, 0, z1.y), opacity);
        // Vertex 2
        _setVertexData(VertexOffset+2, Ogre::Vector3(x2.x, y0, z2.x), opacity);
        // Vertex 3
        _setVertexData(VertexOffset+3, Ogre::Vector3(x2.y, y0, z2.y), opacity);
 
        Ogre::Vector2 x3 = Radius*mAlphaSin*mV2Cos,
                      z3 = Radius*mAlphaSin*mV2Sin;
 
        float y1 = Radius*Ogre::Math::Sin(mBeta);
 
        // Vertex 4
        _setVertexData(VertexOffset+4, Ogre::Vector3(x3.x, y1, z3.x), opacity);
        // Vertex 5
        _setVertexData(VertexOffset+5, Ogre::Vector3(x3.y, y1, z3.y), opacity);
 
        // Vertex 6
        _setVertexData(VertexOffset+6, Ogre::Vector3(0, Radius, 0), opacity);
    }
 
    void GeometryBlock::_setVertexData(const int& index, const Ogre::Vector3& p, const float& o)
    {
        float yDist = -mDistance.y;
        float fallingDistance = mVClouds->getDistanceFallingParams().x*yDist*(Ogre::Vector2(p.x,p.z).length()/mRadius);
        
        if (mVClouds->getDistanceFallingParams().y > 0) // -1 means no max falling
        {
            if (fallingDistance > 0)
            {
                if (fallingDistance > mVClouds->getDistanceFallingParams().y)
                {
                    fallingDistance = mVClouds->getDistanceFallingParams().y;
                }
            }
            else
            {
                if (-fallingDistance > mVClouds->getDistanceFallingParams().y)
                {
                    fallingDistance = -mVClouds->getDistanceFallingParams().y;
                }
            }
        }
 
        fallingDistance *= Ogre::Math::Sign(yDist);
        
        // Position
        mVertices[index].x = p.x;
        if (yDist < -mHeight/2)
        {
            // Over-cloud
            mVertices[index].y = mHeight - p.y;
        }
        else // Under-cloud
        {
            mVertices[index].y = p.y - fallingDistance;
        }
        mVertices[index].z = p.z;
 
        // 3D coords (Z-UP)
        float scale = mVClouds->getCloudFieldScale()/mRadius;
        mVertices[index].xc = (p.x+mWorldOffset.x)*scale;
        mVertices[index].yc = (p.z+mWorldOffset.y)*scale;
        mVertices[index].zc = Ogre::Math::Clamp<Ogre::Real>(p.y/mHeight, 0, 1);
        if (yDist < -mHeight/2)
        {
            // Over-cloud
            mVertices[index].zc = 1.0f - mVertices[index].zc;
        }
 
        // Noise coords
        float noise_scale = mVClouds->getNoiseScale()/mRadius;
        float xz_length_radius = Ogre::Vector2(p.x,p.z).length() / mRadius;
        Ogre::Vector3 origin = Ogre::Vector3(0,-(mEntity->getParentSceneNode()->_getDerivedPosition().y-mCamera->getDerivedPosition().y) -mRadius*(0.5f+0.5f*Ogre::Vector2(p.x,p.z).length()/mRadius),0);
        Ogre::Vector3 dir = (p-origin).normalisedCopy();
        float hip = Ogre::Math::Sqrt(Ogre::Math::Pow(xz_length_radius * mRadius, 2) + Ogre::Math::Pow(origin.y, 2));
        Ogre::Vector3 uv = dir*hip; // Only x/z, += origin doesn't need
        mVertices[index].u = (uv.x+mWorldOffset.x)*noise_scale;
        mVertices[index].v = (uv.z+mWorldOffset.y)*noise_scale;
 
        // Opacity
        float dist = (mDistance - Ogre::Vector3(p.x, p.y - fallingDistance, p.z)).length();
        float att = Ogre::Math::Clamp((dist-mA/3.25f)/(mA/3.25f),0.0f,1.0f);
        mVertices[index].o = o * att * mVClouds->getGlobalOpacity();
    }
 
    const bool GeometryBlock::isInFrustum(Ogre::Camera *c) const
    {
        if (!mCreated)
        {
            return false;
        }
 
        // TODO: Use a world bounding box for each geometry zone, this way the
        // culling is going to be more acurrated and the geometry falling is going to be culled
        // when the falling factor is bigger than 1.
        return c->isVisible(mEntity->getParentSceneNode()->_getWorldAABB());
    }
}}