1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
uniform sampler2D DistanceMap;
uniform sampler2D NormalMap;
uniform sampler2D ImageMap;
varying vec3 vertex_normal;
varying vec4 vertex_position;
varying vec4 MapCoord;
void main()
{
const vec4 lightSpecular = vec4(0.8, 0.8, 0.8, 1.0);
const vec4 matSpecular = vec4(1.0, 1.0, 1.0, 1.0);
const float matShininess = 100.0;
const vec2 point_five = vec2(0.5);
// Need the normalized eye direction and surface normal vectors to
// compute the refraction vector through the "front" surface of the object.
vec3 eye_direction = normalize(-vertex_position.xyz);
vec3 normalized_normal = normalize(vertex_normal);
vec3 front_refraction = refract(eye_direction, normalized_normal, 1.5);
// Offset the base map coordinate by the refaction vector, and re-normalize
// to texture coordinate space [0, 1].
vec4 mc_perspective = MapCoord / MapCoord.w;
vec4 distance_value = texture2D(DistanceMap, mc_perspective.st);
float frontToBack = distance_value.z - mc_perspective.z;
vec3 back_position = (front_refraction - vertex_position) + frontToBack;
vec2 normcoord = (mc_perspective.st + front_refraction.st + point_five) * point_five;
vec3 back_normal = texture2D(NormalMap, normcoord).xyz;
// Now refract again, using the normal from the lookup.
vec3 back_refraction = refract(back_position, back_normal.xyz, 1.0);
vec2 imagecoord = (normcoord + back_refraction.st + point_five) * point_five;
vec4 texel = texture2D(ImageMap, imagecoord);
// Add in a specular component
vec3 light_direction = normalize(vertex_position.xyz/vertex_position.w -
LightSourcePosition.xyz/LightSourcePosition.w);
vec3 reflection = reflect(light_direction, normalized_normal);
float specularTerm = pow(max(0.0, dot(reflection, eye_direction)), matShininess);
vec4 specular = (lightSpecular * matSpecular);
gl_FragColor = (specular * specularTerm) + texel;
}
|
