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Lib Vectors - Shader API | Substance 3D Painter

Lib Vectors - Shader API

lib-vectors.glsl

Public Functions: computeLocalFrame getEyeVec tangentSpaceToWorldSpace worldSpaceToTangentSpace

Import from library

import lib-normal.glsl
import lib-normal.glsl
import lib-normal.glsl

Which view is shaded.

//: param auto is_2d_view
uniform bool is2DView;
//: param auto is_2d_view uniform bool is2DView;
//: param auto is_2d_view 
uniform bool is2DView;

What kind of projection is used.

//: param auto is_perspective_projection
uniform bool is_perspective;
//: param auto is_perspective_projection uniform bool is_perspective;
//: param auto is_perspective_projection 
uniform bool is_perspective;

Eye position in world space.

//: param auto world_eye_position
uniform vec3 camera_pos;
//: param auto world_eye_position uniform vec3 camera_pos;
//: 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);
}
//: param auto world_camera_direction uniform vec3 camera_dir; //: param auto facing uniform int facing; bool isBackFace() { return facing == -1 || (facing == 0 && !gl_FrontFacing); }
//: 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;
}
vec3 getEyeVec(vec3 position) { return is_perspective ? normalize(camera_pos - position) : -camera_dir; }
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);
}
vec3 tangentSpaceToWorldSpace(vec3 vecTS, V2F inputs) { return normalize( vecTS.x * inputs.tangent + vecTS.y * inputs.bitangent + vecTS.z * inputs.normal); }
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));
}
vec3 worldSpaceToTangentSpace(vec3 vecWS, V2F inputs) { // Assume the transformation is orthogonal return normalize(vecWS * mat3(inputs.tangent, inputs.bitangent, inputs.normal)); }
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;
};
struct LocalVectors { vec3 vertexNormal; vec3 tangent, bitangent, normal, eye; };
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;
}
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; }
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);
}
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); }
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); 
} 
 

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