Test code
//----------------------------------------------------------------------------------------------------
// Fresnel test shader by hanecci
//
// This software is released under the Unlicense. ( http://unlicense.org/ )
//
// This is free and unencumbered software released into the public domain.
// Anyone is free to copy, modify, publish, use, compile, sell, or
// distribute this software, either in source code form or as a compiled
// binary, for any purpose, commercial or non-commercial, and by any means.
//
//----------------------------------------------------------------------------------------------------
in vec3 normal;
in vec3 half_vec;
uniform vec3 f0;
#define FRESNEL_MODE ( 0 )
#define FRESNEL_NO_OPT ( 0 )
#define FRESNEL_BLACK_OPS2 ( 1 )
#define FRESNEL_SEBASTEIN0 ( 2 )
#define FRESNEL_SEBASTEIN1 ( 3 )
#define FRESNEL_DISNEY ( 4 )
void main( void )
{
vec4 color = vec4( 0.0, 0.0, 0.0, 0.0 );
float dot_n_h = dot( normal, half_vec );
#if ( FRESNEL_MODE == FRESNEL_NO_OPT )
color.rgb = f0 + ( vec3(1.0) - f0 ) * pow( dot_n_h, 5 );
#elif ( FRESNEL_MODE == FRESNEL_BLACK_OPS2 )
color.rgb = f0 + ( vec3(1.0) - f0 ) * exp2( - 10.0 * dot_n_h );
#elif ( FRESNEL_MODE == FRESNEL_SEBASTEIN0 )
color.rgb = f0 + ( vec3(1.0) - f0 ) * exp2( - 8.35 * dot_n_h );
#elif ( FRESNEL_MODE == FRESNEL_SEBASTEIN1 )
color.rgb = f0 + ( vec3(1.0) - f0 ) * exp2( ( - 5.55473 * dot_n_h - 6.98316 ) * dot_n_h );
#elif ( FRESNEL_MODE == FRESNEL_DISNEY )
float value2 = dot_n_h * dot_n_h;
float value5 = value2 * value2 * dot_n_h;
color.rgb = mix( f0, vec3(1), value5 );
#endif
gl_FragColor = color;
}
No optimization
; -------- Disassembly --------------------
00 ALU: ADDR(32) CNT(16)
0 x: DOT4 ____, R0.x, R1.x
y: DOT4 ____, R0.y, R1.y
z: DOT4 ____, R0.z, R1.z
w: DOT4 ____, (0x80000000, -0.0f).x, 0.0f
t: ADD R0.y, -C0.x, 1.0f
1 x: ADD R0.x, -C0.y, 1.0f
w: ADD R0.w, -C0.z, 1.0f
t: LOG_sat ____, PV0.x
2 w: MUL ____, PS1, (0x40A00000, 5.0f).x
t: MOV R1.w, 0.0f
3 t: EXP_e ____, PV2.w
4 x: MULADD R1.x, PS3, R0.y, C0.x
y: MULADD R1.y, PS3, R0.x, C0.y
z: MULADD R1.z, PS3, R0.w, C0.z
01 EXP_DONE: PIX0, R1
END_OF_PROGRAM
; -------- Disassembly --------------------
00 ALU: ADDR(32) CNT(15)
0 x: DOT4 ____, R0.x, R1.x
y: DOT4 ____, R0.y, R1.y
z: DOT4 ____, R0.z, R1.z
w: DOT4 ____, (0x80000000, -0.0f).x, 0.0f
t: ADD R0.y, -C0.x, 1.0f
1 x: ADD R0.x, -C0.y, 1.0f
y: ADD R1.y, -C0.z, 1.0f
w: MUL ____, PV0.x, (0xC1200000, -10.0f).x
t: MOV R2.w, 0.0f
2 t: EXP_e ____, PV1.w
3 x: MULADD R2.x, PS2, R0.y, C0.x
y: MULADD R2.y, PS2, R0.x, C0.y
z: MULADD R2.z, PS2, R1.y, C0.z VEC_021
01 EXP_DONE: PIX0, R2
END_OF_PROGRAM
"Approximate Fresnel with Spherical Gaussian"
- "Approximate Fresnel with Spherical Gaussian" by Sébastien Lagarde
Version0
; -------- Disassembly --------------------
00 ALU: ADDR(32) CNT(15)
0 x: DOT4 ____, R0.x, R1.x
y: DOT4 ____, R0.y, R1.y
z: DOT4 ____, R0.z, R1.z
w: DOT4 ____, (0x80000000, -0.0f).x, 0.0f
t: ADD R0.y, -C0.x, 1.0f
1 x: ADD R0.x, -C0.y, 1.0f
y: ADD R1.y, -C0.z, 1.0f
w: MUL ____, PV0.x, (0xC105999A, -8.350000381f).x
t: MOV R2.w, 0.0f
2 t: EXP_e ____, PV1.w
3 x: MULADD R2.x, PS2, R0.y, C0.x
y: MULADD R2.y, PS2, R0.x, C0.y
z: MULADD R2.z, PS2, R1.y, C0.z VEC_021
01 EXP_DONE: PIX0, R2
END_OF_PROGRAM
Version1
- "Real Shading in Unreal Engine 4". Brian Karis. SIGGRAPH 2013 Course: Physically Based Shading in Theory and Practice
; -------- Disassembly --------------------
00 ALU: ADDR(32) CNT(16)
0 x: DOT4 ____, R0.x, R1.x
y: DOT4 R0.y, R0.y, R1.y
z: DOT4 ____, R0.z, R1.z
w: DOT4 ____, (0x80000000, -0.0f).x, 0.0f
t: ADD R1.y, -C0.x, 1.0f
1 x: MULADD R127.x, PV0.x, (0xC0B1C059, -5.554729939f).y, (0xC0DF760C, -6.983160019f).x
y: ADD R2.y, -C0.y, 1.0f
w: ADD R0.w, -C0.z, 1.0f
t: MOV R3.w, 0.0f
2 w: MUL ____, R0.y, PV1.x
3 t: EXP_e ____, PV2.w
4 x: MULADD R3.x, PS3, R1.y, C0.x
y: MULADD R3.y, PS3, R2.y, C0.y VEC_021
z: MULADD R3.z, PS3, R0.w, C0.z
01 EXP_DONE: PIX0, R3
END_OF_PROGRAM
Fresnel at Disney BRDF
# Copyright Disney Enterprises, Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License
# and the following modification to it: Section 6 Trademarks.
# deleted and replaced with:
#
# 6. Trademarks. This License does not grant permission to use the
# trade names, trademarks, service marks, or product names of the
# Licensor and its affiliates, except as required for reproducing
# the content of the NOTICE file.
#
# You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0
float SchlickFresnel(float u)
{
float m = clamp(1-u, 0, 1);
float m2 = m*m;
return m2*m2*m; // pow(m,5)
}
float FH = SchlickFresnel(LdotH);
vec3 Fs = mix(Cspec0, vec3(1), FH);; -------- Disassembly --------------------
00 ALU: ADDR(32) CNT(15)
0 x: DOT4 ____, R0.x, R1.x
y: DOT4 R127.y, R0.y, R1.y
z: DOT4 ____, R0.z, R1.z
w: DOT4 ____, (0x80000000, -0.0f).x, 0.0f
t: ADD R126.y, -C0.x, 1.0f
1 x: MUL ____, PV0.x, PV0.x
y: ADD R125.y, -C0.y, 1.0f
w: ADD R127.w, -C0.z, 1.0f
t: MOV R0.w, 0.0f
2 w: MUL ____, PV1.x, PV1.x
3 z: MUL ____, R127.y, PV2.w
4 x: MULADD R0.x, R126.y, PV3.z, C0.x
y: MULADD R0.y, R125.y, PV3.z, C0.y VEC_120
z: MULADD R0.z, R127.w, PV3.z, C0.z
01 EXP_DONE: PIX0, R0
END_OF_PROGRAM
