Step 2:

The building to the left has a texture map applied to it. The texture is passed through the shader. This building is also a simple cube with the texture applied to it. To load the texture I used a tga format texture loader.

The code for the texture shader:

// Vertex shader for drawing with one texture

//receive the light position from the application
uniform vec3 LightPosition;

//sending light intensity to fragment shader
varying float LightIntensity;

const float specularContribution = 0.1;
const float diffuseContribution = 1.0 - specularContribution;

void main(void)
{
//Calculate the position of the vertex in model view coordinates
vec3 ecPosition = vec3 (gl_ModelViewMatrix * gl_Vertex);
vec3 tnorm = normalize(gl_NormalMatrix * gl_Normal);

//Perform the light calculations
//Calculate the vector from vertex to light
vec3 lightVec = normalize(LightPosition - ecPosition);
vec3 reflectVec = reflect(-lightVec, tnorm);
vec3 viewVec = normalize(-ecPosition);

float spec = clamp(dot(reflectVec, viewVec), 0.0, 1.0);
spec = pow(spec, 16.0);

LightIntensity = diffuseContribution * max(dot(lightVec, tnorm), 0.0)
+ specularContribution * spec;

//Pass the texture coordinates to the fragment shader
gl_TexCoord[0] = gl_MultiTexCoord0;
gl_Position = ftransform();
}

// Fragment shader for drawing with one texture

//Receive light intensity from vertex shader
varying float LightIntensity;

//Receive texture information from the application
uniform sampler2D EarthTexture;

void main (void)
{
//Get color from texture coordinates
vec3 lightColor = vec3 (texture2D(EarthTexture, gl_TexCoord[0].st));
//Set fragment color to color multiplied by light intensity
gl_FragColor = vec4 (lightColor * LightIntensity, 1.0);
}

Source Code