130 lines
No EOL
4.1 KiB
HLSL
130 lines
No EOL
4.1 KiB
HLSL
/// BEGIN THIRD PARTY ///
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/// SOURCE: https://thebookofshaders.com/edit.php#11/2d-snoise-clear.frag ///
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// Some useful functions
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float3 mod289(float3 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
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float2 mod289(float2 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
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float3 permute(float3 x) { return mod289(((x * 34.0) + 1.0) * x); }
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//
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// Description : GLSL 2D simplex noise function
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// Author : Ian McEwan, Ashima Arts
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// Maintainer : ijm
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// Lastmod : 20110822 (ijm)
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// License :
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// Copyright (C) 2011 Ashima Arts. All rights reserved.
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// Distributed under the MIT License. See LICENSE file.
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// https://github.com/ashima/webgl-noise
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//
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float snoise(float2 v)
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{
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// Precompute values for skewed triangular grid
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const float4 C = float4(0.211324865405187,
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// (3.0-sqrt(3.0))/6.0
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0.366025403784439,
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// 0.5*(sqrt(3.0)-1.0)
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-0.577350269189626,
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// -1.0 + 2.0 * C.x
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0.024390243902439);
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// 1.0 / 41.0
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// First corner (x0)
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float2 i = floor(v + dot(v, C.yy));
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float2 x0 = v - i + dot(i, C.xx);
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// Other two corners (x1, x2)
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float2 i1 = float2(0, 0);
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i1 = (x0.x > x0.y) ? float2(1.0, 0.0) : float2(0.0, 1.0);
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float2 x1 = x0.xy + C.xx - i1;
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float2 x2 = x0.xy + C.zz;
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// Do some permutations to avoid
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// truncation effects in permutation
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i = mod289(i);
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float3 p = permute(
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permute(i.y + float3(0.0, i1.y, 1.0))
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+ i.x + float3(0.0, i1.x, 1.0));
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float3 m = max(0.5 - float3(
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dot(x0, x0),
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dot(x1, x1),
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dot(x2, x2)
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), 0.0);
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m = m * m;
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m = m * m;
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// Gradients:
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// 41 pts uniformly over a line, mapped onto a diamond
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// The ring size 17*17 = 289 is close to a multiple
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// of 41 (41*7 = 287)
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float3 x = 2.0 * frac(p * C.www) - 1.0;
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float3 h = abs(x) - 0.5;
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float3 ox = floor(x + 0.5);
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float3 a0 = x - ox;
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// Normalise gradients implicitly by scaling m
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// Approximation of: m *= inversesqrt(a0*a0 + h*h);
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m *= 1.79284291400159 - 0.85373472095314 * (a0 * a0 + h * h);
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// Compute final noise value at P
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float3 g = float3(0, 0, 0);
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g.x = a0.x * x0.x + h.x * x0.y;
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g.yz = a0.yz * float2(x1.x, x2.x) + h.yz * float2(x1.y, x2.y);
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return 130.0 * dot(m, g);
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}
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/// SOURCE: https://thebookofshaders.com/10/ ///
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float random(float2 st)
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{
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return frac(sin(dot(st.xy,
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float2(12.9898, 78.233))) *
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43758.5453123);
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}
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/// END THIRD PARTY ///
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cbuffer ExternalData : register(b0)
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{
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float4 tint;
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float noise;
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}
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// Struct representing the data we expect to receive from earlier pipeline stages
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// - Should match the output of our corresponding vertex shader
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// - The name of the struct itself is unimportant
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// - The variable names don't have to match other shaders (just the semantics)
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// - Each variable must have a semantic, which defines its usage
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struct VertexToPixel
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{
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// Data type
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// |
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// | Name Semantic
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// | | |
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// v v v
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float4 screenPosition : SV_POSITION;
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float2 uv : TEXCOORD;
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};
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// --------------------------------------------------------
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// The entry point (main method) for our pixel shader
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//
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// - Input is the data coming down the pipeline (defined by the struct)
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// - Output is a single color (float4)
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// - Has a special semantic (SV_TARGET), which means
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// "put the output of this into the current render target"
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// - Named "main" because that's the default the shader compiler looks for
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// --------------------------------------------------------
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float4 main(VertexToPixel input) : SV_TARGET
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{
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// Just return the tint
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// - This color (like most values passing through the rasterizer) is
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// interpolated for each pixel between the corresponding vertices
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// of the triangle we're rendering
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return float4(
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sin(snoise(input.uv * noise) + tint.r - random(input.uv)) + (tint.r * 0.5),
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sin(snoise(input.uv * noise) + tint.g - random(input.uv)) + (tint.g * 0.5),
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sin(snoise(input.uv * noise) + tint.b - random(input.uv)) + (tint.b * 0.5),
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cos(random(input.screenPosition)));
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} |