Render shadows in OpenGL

Shadows.cpp

void RenderShadows(const math::CVector2& LightPos), 
    const std::vector<Object*>& shadowCastingObjects)
{
    // Set up rendering modes
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();
    glDisable(GL_BLEND);
    glColor4f(0.3f, 0.3f, 0.3f, 1.0f);   // Dark gray

    for(size_t i = 0; i < shadowCastingObjects.size(); ++i)
    {
        math::CRay2 TopLeft, TopRight, BottomRight, BottomLeft;

        TopLeft.Start       = LightPos;
        TopLeft.End         = shadowCastingObjects[i]->GetPosition();

        TopRight.Start      = LightPos;
        TopRight.End.x      = shadowCastingObjects[i]->GetX() + shadowCastingObjects[i]->GetW();
        TopRight.End.y      = shadowCastingObjects[i]->GetY();

        BottomRight.Start   = LightPos;
        BottomRight.End.x   = shadowCastingObjects[i]->GetX() + shadowCastingObjects[i]->GetW();
        BottomRight.End.y   = shadowCastingObjects[i]->GetY() + shadowCastingObjects[i]->GetH();

        BottomLeft.Start    = LightPos;
        BottomLeft.End.x    = shadowCastingObjects[i]->GetX();
        BottomLeft.End.y    = shadowCastingObjects[i]->GetY() + shadowCastingObjects[i]->GetH();

        CreateShadowRay(LightPos, TopLeft);
        CreateShadowRay(LightPos, TopRight);
        CreateShadowRay(LightPos, BottomRight);
        CreateShadowRay(LightPos, BottomLeft);

        glBegin(GL_QUADS);
        
        if(TopLeft.Start.y < LightPos.y)
        {
            glVertex2f(TopLeft.Start.x, TopLeft.Start.y);
            glVertex2f(TopLeft.End.x, TopLeft.End.y);
            glVertex2f(TopRight.End.x, TopRight.End.y);
            glVertex2f(TopRight.Start.x, TopRight.Start.y);
        }

        if(TopRight.Start.x > LightPos.x)
        {
            glVertex2f(TopRight.Start.x, TopRight.Start.y);
            glVertex2f(TopRight.End.x, TopRight.End.y);
            glVertex2f(BottomRight.End.x, BottomRight.End.y);
            glVertex2f(BottomRight.Start.x, BottomRight.Start.y);
        }
        
        if(BottomRight.Start.y > LightPos.y)
        {
            glVertex2f(BottomRight.Start.x, BottomRight.Start.y);
            glVertex2f(BottomRight.End.x, BottomRight.End.y);
            glVertex2f(BottomLeft.End.x, BottomLeft.End.y);
            glVertex2f(BottomLeft.Start.x, BottomLeft.Start.y);
        }
        
        if(BottomLeft.Start.x < LightPos.x)
        {
            glVertex2f(BottomLeft.Start.x, BottomLeft.Start.y);
            glVertex2f(BottomLeft.End.x, BottomLeft.End.y);
            glVertex2f(TopLeft.End.x, TopLeft.End.y);
            glVertex2f(TopLeft.Start.x, TopLeft.Start.y);
        }
        glEnd();
    }

    // Revert rendering modes.
    glEnable(GL_BLEND);
    glColor4f(1, 1, 1, 1);
    glPopMatrix();
}

// There is a minor bug with this method, when the LightPos.x
// is equal to the RayCast.x value, the shadow is not created
// as intended. When I find a fix, I'll update this code.
// If anyone has a fix, feel free to comment below.
void CWorld::CreateShadowRay(const math::CVector2& LightPos,
    math::CRay2& RayCast)
{
    // Calculate slope
    // m = (y2 - y1) / (x2 - x1)
    float slope = RayCast.GetSlope();

    // Translate the ray from its original position to 
    // being from the vertex to a distance
    // approx. 5000px away.
    RayCast.Start = RayCast.End;

    if(RayCast.End.x > LightPos.x)
    {
        RayCast.End.x += 5000;
        RayCast.End.y += 5000 * slope;
    }
    else if(RayCast.End.x < LightPos.x)
    {
        RayCast.End.x -= 5000;
        RayCast.End.y -= 5000 * slope;
    }    
}