source: OGRE/trunk/ogrenew/Samples/DeferredShading/src/MLight.cpp @ 692

/******************************************************************************
Copyright (c) W.J. van der Laan

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this software  and associated documentation files (the "Software"), to deal in 
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The above copyright notice and this permission notice shall be included in all copies 
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INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
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******************************************************************************/
#include "MLight.h"

#include "OgreStringConverter.h"
#include "OgreException.h"

#include "OgreMesh.h"
#include "OgreSubMesh.h"
#include "OgreResourceGroupManager.h"
#include "OgreMeshManager.h"
#include "OgreHardwareVertexBuffer.h"
#include "OgreHardwarePixelBuffer.h"
#include "OgreHardwareBufferManager.h"

#include "OgreRoot.h"

#include "OgreCamera.h"

#include "MaterialGenerator.h"

using namespace Ogre;
//-----------------------------------------------------------------------
MLight::MLight(MaterialGenerator *sys):
        bIgnoreWorld(false), mGenerator(sys),mPermutation(0)
{
        // Set up geometry
        //setMaterial("DeferredShading/Post/LightMaterial");
        // Set render priority to high (just after normal postprocess)
        setRenderQueueGroup(RENDER_QUEUE_2);
        // Allocate render operation
        mRenderOp.operationType = Ogre::RenderOperation::OT_TRIANGLE_LIST;
        mRenderOp.indexData = 0;
        mRenderOp.vertexData = 0;
        mRenderOp.useIndexes = true;

        // Diffuse and specular colour
        setDiffuseColour(Ogre::ColourValue(1,1,1));
        setSpecularColour(Ogre::ColourValue(0,0,0));
        // Set Attenuation
        setAttenuation(1.0f,0.0f,0.0f);
}
//-----------------------------------------------------------------------
MLight::~MLight()
{
        // need to release IndexData and vertexData created for renderable
    delete mRenderOp.indexData;
    delete mRenderOp.vertexData;
}
//-----------------------------------------------------------------------
void MLight::setAttenuation(float c, float b, float a)
{
        // Set Attenuation parameter to shader
        setCustomParameter(3, Vector4(c, b, a, 0));

        /// There is attenuation? Set material accordingly
        if(c != 1.0f || b != 0.0f || a != 0.0f)
                mPermutation |= MI_ATTENUATED;
        else
                mPermutation &= ~MI_ATTENUATED;

        // Calculate radius from Attenuation
        int threshold_level = 15;// differece of 10-15 levels deemed unnoticable
        float threshold = 1.0f/((float)threshold_level/256.0f); 

        // Use quadratic formula to determine outer radius
        c = c-threshold;
        float d=sqrt(b*b-4*a*c);
        float x=(-2*c)/(b+d);

        rebuildGeometry(x);
}
//-----------------------------------------------------------------------
void MLight::setDiffuseColour(const Ogre::ColourValue &col)
{
        setCustomParameter(1, Vector4(col.r, col.g, col.b, col.a));
}
//-----------------------------------------------------------------------
void MLight::setSpecularColour(const Ogre::ColourValue &col)
{
        setCustomParameter(2, Vector4(col.r, col.g, col.b, col.a));
        /// There is a specular component? Set material accordingly
        
        if(col.r != 0.0f || col.g != 0.0f || col.b != 0.0f)
                mPermutation |= MI_SPECULAR;
        else
                mPermutation &= ~MI_SPECULAR;
                
}
//-----------------------------------------------------------------------
Ogre::ColourValue MLight::getDiffuseColour()
{
        Ogre::Vector4 val = getCustomParameter(1);
        return Ogre::ColourValue(val[0], val[1], val[2], val[3]);
}
//-----------------------------------------------------------------------
Ogre::ColourValue MLight::getSpecularColour()
{
        Ogre::Vector4 val = getCustomParameter(2);
        return Ogre::ColourValue(val[0], val[1], val[2], val[3]);
}
//-----------------------------------------------------------------------
void MLight::rebuildGeometry(float radius)
{
        // Scale node to radius
        
        if(radius > 10000.0f)
        {
                createRectangle2D();
                mPermutation |= MI_QUAD;
        }
        else
        {
                /// XXX some more intelligent expression for rings and segments
                createSphere(radius, 5, 5);
                mPermutation &= ~MI_QUAD;
        }       
}
//-----------------------------------------------------------------------
void MLight::createRectangle2D()
{
        /// XXX this RenderOp should really be re-used between MLight objects,
        /// not generated every time
        delete mRenderOp.vertexData; 
        delete mRenderOp.indexData; 
        mRenderOp.vertexData = new VertexData();
    mRenderOp.indexData = 0;

    mRenderOp.vertexData->vertexCount = 4; 
    mRenderOp.vertexData->vertexStart = 0; 
    mRenderOp.operationType = RenderOperation::OT_TRIANGLE_STRIP; 
    mRenderOp.useIndexes = false; 

    VertexDeclaration* decl = mRenderOp.vertexData->vertexDeclaration;
    VertexBufferBinding* bind = mRenderOp.vertexData->vertexBufferBinding;

    decl->addElement(0, 0, VET_FLOAT3, VES_POSITION);

    HardwareVertexBufferSharedPtr vbuf = 
        HardwareBufferManager::getSingleton().createVertexBuffer(
        decl->getVertexSize(0),
        mRenderOp.vertexData->vertexCount,
        HardwareBuffer::HBU_STATIC_WRITE_ONLY);

    // Bind buffer
    bind->setBinding(0, vbuf);
        // Upload data
        float data[]={
                -1,1,-1,  // corner 1
                -1,-1,-1, // corner 2
                1,1,-1,   // corner 3
                1,-1,-1}; // corner 4
        vbuf->writeData(0, sizeof(data), data, true);

        // Set bounding
    setBoundingBox(AxisAlignedBox(-10000,-10000,-10000,10000,10000,10000));
        mRadius = 15000;
        bIgnoreWorld = true;
}
//-----------------------------------------------------------------------
void MLight::createSphere(const float r, const int nRings, const int nSegments)
{
        delete mRenderOp.vertexData; 
        delete mRenderOp.indexData;
        mRenderOp.operationType = Ogre::RenderOperation::OT_TRIANGLE_LIST;
        mRenderOp.indexData = new IndexData();
        mRenderOp.vertexData = new VertexData();
        mRenderOp.useIndexes = true;

        VertexData* vertexData = mRenderOp.vertexData;
        IndexData* indexData = mRenderOp.indexData;

        // define the vertex format
        VertexDeclaration* vertexDecl = vertexData->vertexDeclaration;
        size_t currOffset = 0;
        // only generate positions
        vertexDecl->addElement(0, currOffset, VET_FLOAT3, VES_POSITION);
        currOffset += VertexElement::getTypeSize(VET_FLOAT3);
        // allocate the vertex buffer
        vertexData->vertexCount = (nRings + 1) * (nSegments+1);
        HardwareVertexBufferSharedPtr vBuf = HardwareBufferManager::getSingleton().createVertexBuffer(vertexDecl->getVertexSize(0), vertexData->vertexCount, HardwareBuffer::HBU_STATIC_WRITE_ONLY, false);
        VertexBufferBinding* binding = vertexData->vertexBufferBinding;
        binding->setBinding(0, vBuf);
        Real* pVertex = static_cast<Real*>(vBuf->lock(HardwareBuffer::HBL_DISCARD));

        // allocate index buffer
        indexData->indexCount = 6 * nRings * (nSegments + 1);
        indexData->indexBuffer = HardwareBufferManager::getSingleton().createIndexBuffer(HardwareIndexBuffer::IT_16BIT, indexData->indexCount, HardwareBuffer::HBU_STATIC_WRITE_ONLY, false);
        HardwareIndexBufferSharedPtr iBuf = indexData->indexBuffer;
        unsigned short* pIndices = static_cast<unsigned short*>(iBuf->lock(HardwareBuffer::HBL_DISCARD));

        float fDeltaRingAngle = (Math::PI / nRings);
        float fDeltaSegAngle = (2 * Math::PI / nSegments);
        unsigned short wVerticeIndex = 0 ;

        // Generate the group of rings for the sphere
        for( int ring = 0; ring <= nRings; ring++ ) {
                float r0 = r * sinf (ring * fDeltaRingAngle);
                float y0 = r * cosf (ring * fDeltaRingAngle);

                // Generate the group of segments for the current ring
                for(int seg = 0; seg <= nSegments; seg++) {
                        float x0 = r0 * sinf(seg * fDeltaSegAngle);
                        float z0 = r0 * cosf(seg * fDeltaSegAngle);

                        // Add one vertex to the strip which makes up the sphere
                        *pVertex++ = x0;
                        *pVertex++ = y0;
                        *pVertex++ = z0;

                        if (ring != nRings) 
                        {
                // each vertex (except the last) has six indicies pointing to it
                                *pIndices++ = wVerticeIndex + nSegments + 1;
                                *pIndices++ = wVerticeIndex;               
                                *pIndices++ = wVerticeIndex + nSegments;
                                *pIndices++ = wVerticeIndex + nSegments + 1;
                                *pIndices++ = wVerticeIndex + 1;
                                *pIndices++ = wVerticeIndex;
                                wVerticeIndex ++;
                        }
                }; // end for seg
        } // end for ring

        // Unlock
        vBuf->unlock();
        iBuf->unlock();

        // Set bounding box and sphere
        setBoundingBox( AxisAlignedBox( Vector3(-r, -r, -r), Vector3(r, r, r) ) );
        mRadius = r;
        bIgnoreWorld = false;
}                                                                
//-----------------------------------------------------------------------
Real MLight::getBoundingRadius(void) const
{
        return mRadius;
}
//-----------------------------------------------------------------------
Ogre::Real MLight::getSquaredViewDepth(const Ogre::Camera* cam) const
{
        if(bIgnoreWorld)
        {
                return 0.0f;
        }
        else
        {
                Vector3 dist = cam->getDerivedPosition() - getWorldPosition();                                                                       
                return dist.squaredLength();
        }
}
//-----------------------------------------------------------------------
const MaterialPtr& MLight::getMaterial(void) const
{
        return mGenerator->getMaterial(mPermutation);
}