65 lines
2 KiB
GLSL
65 lines
2 KiB
GLSL
#version 330 core
|
|
|
|
uniform mat4 fg_ProjectionMatrixInverse;
|
|
uniform vec2 fg_NearFar;
|
|
|
|
// Octahedron normal encoding
|
|
// https://knarkowicz.wordpress.com/2014/04/16/octahedron-normal-vector-encoding/
|
|
vec2 msign(vec2 v)
|
|
{
|
|
return vec2((v.x >= 0.0) ? 1.0 : -1.0,
|
|
(v.y >= 0.0) ? 1.0 : -1.0);
|
|
}
|
|
|
|
vec2 encodeNormal(vec3 n)
|
|
{
|
|
n /= (abs(n.x) + abs(n.y) + abs(n.z));
|
|
n.xy = (n.z >= 0) ? n.xy : (1.0 - abs(n.yx)) * msign(n.xy);
|
|
n.xy = n.xy * 0.5 + 0.5;
|
|
return n.xy;
|
|
}
|
|
|
|
vec3 decodeNormal(vec2 f)
|
|
{
|
|
f = f * 2.0 - 1.0;
|
|
vec3 n = vec3(f, 1.0 - abs(f.x) - abs(f.y));
|
|
float t = max(-n.z, 0.0);
|
|
n.x += (n.x > 0.0) ? -t : t;
|
|
n.y += (n.y > 0.0) ? -t : t;
|
|
return normalize(n);
|
|
}
|
|
|
|
// Given a 2D coordinate in the range [0,1] and a depth value from a depth
|
|
// buffer, also in the [0,1] range, return the view space position.
|
|
vec3 positionFromDepth(vec2 pos, float depth, mat4 projMatrixInverse)
|
|
{
|
|
// We are using a reversed depth buffer. 1.0 corresponds to the near plane
|
|
// and 0.0 to the far plane. We convert this back to clip space by doing
|
|
// 1.0 - depth to undo the depth reversal
|
|
// 2.0 * depth - 1.0 to transform it to clip space [-1,1]
|
|
vec4 clipSpacePos = vec4(pos * 2.0 - 1.0, 1.0 - depth * 2.0, 1.0);
|
|
vec4 viewSpacePos = projMatrixInverse * clipSpacePos;
|
|
viewSpacePos.xyz /= viewSpacePos.w;
|
|
return viewSpacePos.xyz;
|
|
}
|
|
|
|
vec3 positionFromDepth(vec2 pos, float depth)
|
|
{
|
|
return positionFromDepth(pos, depth, fg_ProjectionMatrixInverse);
|
|
}
|
|
|
|
// http://www.geeks3d.com/20091216/geexlab-how-to-visualize-the-depth-buffer-in-glsl/
|
|
float linearizeDepth(float depth)
|
|
{
|
|
float z = 1.0 - depth; // Undo the depth reversal
|
|
return 2.0 * fg_NearFar.x
|
|
/ (fg_NearFar.y + fg_NearFar.x - z * (fg_NearFar.y - fg_NearFar.x));
|
|
}
|
|
|
|
vec3 decodeSRGB(vec3 screenRGB)
|
|
{
|
|
vec3 a = screenRGB / 12.92;
|
|
vec3 b = pow((screenRGB + 0.055) / 1.055, vec3(2.4));
|
|
vec3 c = step(vec3(0.04045), screenRGB);
|
|
return mix(a, b, c);
|
|
}
|