mirror of
https://bitbucket.org/CPMADevs/cnq3
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92 lines
2.7 KiB
HLSL
92 lines
2.7 KiB
HLSL
/*
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===========================================================================
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Copyright (C) 2023 Gian 'myT' Schellenbaum
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This file is part of Challenge Quake 3 (CNQ3).
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Challenge Quake 3 is free software; you can redistribute it
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and/or modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the License,
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or (at your option) any later version.
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Challenge Quake 3 is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Challenge Quake 3. If not, see <https://www.gnu.org/licenses/>.
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===========================================================================
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*/
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// helper functions used by multiple shader files
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#if !defined(DISABLE_PRAGMA_ONCE)
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#pragma once
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#endif
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float4 MakeGreyscale(float4 input, float amount)
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{
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float grey = dot(input.rgb, float3(0.299, 0.587, 0.114));
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float4 result = lerp(input, float4(grey, grey, grey, input.a), amount);
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return result;
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}
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/*
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f = far clip plane distance
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n = near clip plane distance
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exp = exponential depth value (as stored in the Z-buffer)
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2 * f * n B
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linear(exp) = ----------------------- = -------
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(f + n) - exp * (f - n) exp - A
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f + n -2 * f * n
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with A = ----- and B = ----------
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f - n f - n
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*/
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float LinearDepth(float zwDepth, float proj22, float proj32)
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{
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return proj32 / (zwDepth - proj22);
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}
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// this is from Morgan McGuire's "Hashed Alpha Testing" paper
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float Hash(float2 input)
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{
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return frac(1.0e4 * sin(17.0 * input.x + 0.1 * input.y) + (0.1 + abs(sin(13.0 * input.y + input.x))));
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}
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float LinearColor(float color, float invBrightness, float invGamma)
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{
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return pow(abs(color * invBrightness), invGamma) * sign(color);
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}
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float4 Dither(float4 color, float3 position, float seed, float noiseScale, float invBrightness, float invGamma)
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{
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float2 newSeed = position.xy + float2(0.6849, 0.6849) * seed + float2(position.z, position.z);
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float noise = (noiseScale / 255.0) * LinearColor(Hash(newSeed) - 0.5, invBrightness, invGamma);
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return color + float4(noise, noise, noise, 0.0);
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}
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// from NVIDIA's 2007 "Soft Particles" whitepaper by Tristan Lorach
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float Contrast(float d, float power)
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{
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bool aboveHalf = d > 0.5;
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float base = saturate(2.0 * (aboveHalf ? (1.0 - d) : d));
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float r = 0.5 * pow(base, power);
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return aboveHalf ? (1.0 - r) : r;
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}
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float GetBitAsFloat(uint bits, uint bitIndex)
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{
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return (bits & (1u << bitIndex)) ? 1.0 : 0.0;
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}
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float2 UnpackHalf2(uint data)
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{
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return float2(f16tof32(data), f16tof32(data >> 16));
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}
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