One can evaluate the lighting equation, then combine with the colour supplied by a texture in the fragment shader.

vec3 vColour = PhongModel(p, n);

// Get the texel colour from the texture sampler
vec4 vTexColour = texture(sampler0, vTexCoord);

// Combine object colour and texture
vec4 vMixedColour = vTexColour * vec4(vColour, 1.0f);

High