Lib Vectors - Shader API
lib-vectors.glsl
Public Functions: computeLocalFrame getEyeVec tangentSpaceToWorldSpace worldSpaceToTangentSpace
Import from library
import lib-normal.glsl
Which view is shaded.
//: param auto is_2d_view
uniform bool is2DView;
What kind of projection is used.
//: param auto is_perspective_projection
uniform bool is_perspective;
Eye position in world space.
//: param auto world_eye_position
uniform vec3 camera_pos;
Camera orientation in world space.
//: param auto world_camera_direction
uniform vec3 camera_dir;
//: param auto facing
uniform int facing;
bool isBackFace() {
return facing == -1 || (facing == 0 && !gl_FrontFacing);
}
Compute the world space eye vector
vec3 getEyeVec(vec3 position) {
return is_perspective ?
normalize(camera_pos - position) :
-camera_dir;
}
Convert a vector from tangent space to world space
vec3 tangentSpaceToWorldSpace(vec3 vecTS, V2F inputs) {
return normalize(
vecTS.x * inputs.tangent +
vecTS.y * inputs.bitangent +
vecTS.z * inputs.normal);
}
Convert a vector from world space to tangent space
vec3 worldSpaceToTangentSpace(vec3 vecWS, V2F inputs) {
// Assume the transformation is orthogonal
return normalize(vecWS * mat3(inputs.tangent, inputs.bitangent, inputs.normal));
}
Local frame of vertex in world space
struct LocalVectors {
vec3 vertexNormal;
vec3 tangent, bitangent, normal, eye;
};
Compute local frame from custom world space normal and anisotropy angle
LocalVectors computeLocalFrame(V2F inputs, vec3 normal, float anisoAngle) {
LocalVectors vectors;
vectors.vertexNormal = inputs.normal;
vectors.normal = normal;
// Flip the normals for back facing polygons
if (isBackFace()) {
vectors.vertexNormal = -vectors.vertexNormal;
vectors.normal = -vectors.normal;
}
vectors.eye = is2DView ?
vectors.normal : // In 2D view, put view vector along the normal
getEyeVec(inputs.position);
// Trick to remove black artifacts
// Backface ? place the eye at the opposite - removes black zones
if (dot(vectors.eye, vectors.normal) < 0.0) {
vectors.eye = reflect(vectors.eye, vectors.normal);
}
// Create a local frame for BRDF work
vec3 tangent = normalize(
inputs.tangent
* vectors.normal * dot(inputs.tangent, vectors.normal)
);
vec3 bitangent = normalize(
inputs.bitangent
* vectors.normal * dot(inputs.bitangent, vectors.normal)
* tangent * dot(inputs.bitangent, tangent)
);
float cosAngle = cos(anisoAngle);
float sinAngle = sin(anisoAngle);
vectors.tangent = cosAngle * tangent - sinAngle * bitangent;
vectors.bitangent = cosAngle * bitangent + sinAngle * tangent;
return vectors;
}
Compute local frame from mesh and document height and normals
LocalVectors computeLocalFrame(V2F inputs) {
// Get world space normal
vec3 normal = computeWSNormal(inputs.sparse_coord, inputs.tangent, inputs.bitangent, inputs.normal);
return computeLocalFrame(inputs, normal, 0.0);
}
recommendation-more-help
4517c71e-0531-47f5-b14d-d3b9de4d0104