HW3: Reflective Bump-Mapped Arch

• Include some sort of arch. It can be as ornate as the Arc de Triomphe, or as simple as a Bower Bird nest.
• Include bump-mapped reflections. To bump-map a surface, you move the normal slightly, by a location-dependent normal perturbation. The typical way to do this is to sample a 3D noise texture at the world coordinates location, shift the read-in values from the range 0 ... 1 down to -0.5 ... +0.5, scale the noise down to a reasonable level, and finally add this to your current normal:

       vec3 perturb=0.1*(vec3(texture3D(noisetex,vec3(hit_point)))-vec3(0.5));
       normal=normalize(normal+perturb);

  It looks best if you apply the bump map both to the lighting (especially the specular highlight) and the reflections.

	int sz=32; /* RGBA 32 x 32 x 32 */
	float *noise=new float[4*sz*sz*sz];
	for (int z=0;z<sz;z++) 
	for (int y=0;y<sz;y++) 
	for (int x=0;x<sz;x++) 
	for (int chan=0;chan<4;chan++) {
		float r=(rand()&0xfff)*(1.0/0xfff);
		noise[chan+4*(x+sz*(y+sz*z))]=r;
	}
	gluBuild3DMipmaps(GL_TEXTURE_3D,GL_RGBA8,
		sz,sz,sz,
		GL_RGBA,GL_FLOAT,noise);
	glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR);
	glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
	glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MAX_ANISOTROPY_EXT,8);
	delete[] noise;

        glTexImage3D(GL_TEXTURE_3D,0,GL_RGBA8,
            sz,sz,sz,0,
            GL_RGBA,GL_FLOAT,noise);
        glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
        glTexParameteri(GL_TEXTURE_3D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);