Basic fog functions for GLSL, generic but intended for use with glslify.
Here's a hypothetical example of linear fog calculated in a vertex shader:
#define FOG_START 100
#define FOG_END 500
uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;
attribute vec3 position;
varying float fogAmount;
#pragma glslify: fog_linear = require(glsl-fog/linear)
void main() {
gl_Position = projection * view * model * vec4(positon, 1.0);
float fogDistance = length(gl_Position.xyz);
fogAmount = fog_linear(fogDistance, FOG_START, FOG_END);
}And another (separate) example using exp/exp2 per-pixel fog:
#define FOG_DENSITY 0.05
varying vec4 vertexColor;
// Take your pick: these should be usable interchangeably.
#pragma glslify: fog_exp2 = require(glsl-fog/exp2)
#pragma glslify: fog_exp = require(glsl-fog/exp)
void main() {
float fogDistance = gl_FragCoord.z / gl_FragCoord.w;
float fogAmount = fog_exp2(fogDistance, FOG_DENSITY);
const float fogColor = vec4(1.0); // white
gl_FragColor = mix(vertexColor, fogColor, fogAmount);
}MIT. See LICENSE.md for details.