approximate face normal in the fragment shader
npm install glsl-face-normal
Approximates face normals in the fragment shader for flat shading from the position in camera space.
Note: You need to enable GL_OES_standard_derivatives.
Fragment:
``glsl
#extension GL_OES_standard_derivatives : enable
varying vec3 vViewPos;
#pragma glslify: faceNormal = require('glsl-face-normal')
void main() {
vec3 normal = faceNormal(vViewPos);
//... lighting
}
`
Vertex:
`glsl
varying vec3 vViewPos;
void main() {
vec4 pos = vec4(position, 1.0);
vec4 mpos = modelViewMatrix * pos;
gl_Position = projectionMatrix * mpos;
vViewPos = -mpos.xyz;
}
`
#### vec3 normal = faceNormal(vec3 pos)
Approximates the face normal from the given pos`, which is typically the position in camera-space.
For better precision, you can use the eye relative position instead.
MIT. See LICENSE.md for details.