src/Shader.cpp

Go to the documentation of this file.

#include "Shader.h"

#include <cassert>

#include "Primitive.h"
#include "TexCoordinate.h"
#include "RGBAColor.h"
#include "Texture.h"


Shader::Shader(Scene* scene)        
    : mScene(scene),
      mBumpTexture(0),
      mBumpCoeff(1.0f)
{
    assert(scene);
}


unsigned int Shader::textureCount() const
{
    return mTextures.size();
}

void Shader::addTexture(Texture* tex)
{
    assert(tex);
    mTextures.push_back(tex);
}

void Shader::removeTexture(Texture* tex)
{
    for (std::vector<Texture*>::iterator it=mTextures.begin(); it != mTextures.end(); )
    {
        if ((*it) == tex)
            it = mTextures.erase(it);
        else
            it++;
    }
}

const Texture * Shader::texture(unsigned int i) const
{
    if (i >= textureCount())
        return NULL;
    return mTextures[i];
}

const Texture* Shader::bumpTexture() const
{
    assert(mBumpTexture!=0);
    return mBumpTexture;
}

void Shader::setBumpTexture(Texture* tex)
{
    mBumpTexture = tex;
}

const Vec3f Shader::normal(const Ray &  ray) const
{
    if(mBumpTexture==0)
    {
         return ray.hit()->normal(ray);
    }
    else
    {
        const TexCoordinate tex = ray.hit()->texCoord(ray);

        Vec3f dPdu, dPdv;
        ray.hit()->axes(ray, dPdu, dPdv);
   
        const float deltax = 1.0f / mBumpTexture->resX();   //one pixel step
        const float deltay = 1.0f / mBumpTexture->resY();
        const RGBAColor value = mBumpTexture->texel(tex.x(),tex.y());
      
        const TexCoordinate xplus1(tex.x() + deltax, tex.y()         );
        const TexCoordinate yplus1(tex.x()         , tex.y() + deltay);

        //aprocimate the derivates for the texture
        const float du = mBumpTexture->texel( xplus1 ).r() - value.r();
        const float dv = mBumpTexture->texel( yplus1 ).r() - value.r();
        const Vec3f normal = ray.hit()->normal(ray);

        //new normal as in the bump mapping formula
        const Vec3f newnormal = normal + mBumpCoeff * (du*dPdu + dv*dPdv);

        return newnormal.normal();
    }
}

---