Graphics Reference
In-Depth Information
Example 14-2
Per-Fragment Lighting Fragment Shader
(continued)
uniform sampler2D s_baseMap;
uniform sampler2D s_bumpMap;
in vec2 v_texcoord;
in vec3 v_viewDirection;
in vec3 v_lightDirection;
layout(location = 0) out vec4 fragColor;
void main( void )
{
// Fetch base map color
vec4 baseColor = texture(s_baseMap, v_texcoord);
// Fetch the tangent space normal from normal map
vec3 normal = texture(s_bumpMap, v_texcoord).xyz;
// Scale and bias from [0, 1] to [−1, 1] and
// normalize
normal = normalize(normal * 2.0 − 1.0);
// Normalize the light direction and view
// direction
vec3 lightDirection = normalize(v_lightDirection);
vec3 viewDirection = normalize(v_viewDirection);
// Compute N.L
float nDotL = dot(normal, lightDirection);
// Compute reflection vector
vec3 reflection = (2.0 * normal * nDotL) −
lightDirection;
// Compute R.V
float rDotV =
max(0.0, dot(reflection, viewDirection));
// Compute ambient term
vec4 ambient = u_ambient * baseColor;
// Compute diffuse term
vec4 diffuse = u_diffuse * nDotL * baseColor;
// Compute specular term
vec4 specular = u_specular *
pow(rDotV, u_specularPower);
// Output final color
fragColor = ambient + diffuse + specular;
}
