mame/hlsl/distortion.fx

333 lines
9.5 KiB
HLSL

// license:BSD-3-Clause
// copyright-holders:ImJezze
//-----------------------------------------------------------------------------
// Distortion Effect
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// Sampler Definitions
//-----------------------------------------------------------------------------
texture DiffuseTexture;
sampler DiffuseSampler = sampler_state
{
Texture = <DiffuseTexture>;
MipFilter = LINEAR;
MinFilter = LINEAR;
MagFilter = LINEAR;
AddressU = CLAMP;
AddressV = CLAMP;
AddressW = CLAMP;
};
//-----------------------------------------------------------------------------
// Vertex Definitions
//-----------------------------------------------------------------------------
struct VS_INPUT
{
float4 Position : POSITION;
float4 Color : COLOR0;
float2 TexCoord : TEXCOORD0;
};
struct VS_OUTPUT
{
float4 Position : POSITION;
float4 Color : COLOR0;
float2 TexCoord : TEXCOORD0;
};
struct PS_INPUT
{
float4 Color : COLOR0;
float2 TexCoord : TEXCOORD0;
};
//-----------------------------------------------------------------------------
// Constants
//-----------------------------------------------------------------------------
static const float Epsilon = 1.0e-7f;
static const float PI = 3.1415927f;
static const float E = 2.7182817f;
static const float Gelfond = 23.140692f; // e^pi (Gelfond constant)
static const float GelfondSchneider = 2.6651442f; // 2^sqrt(2) (Gelfond-Schneider constant)
//-----------------------------------------------------------------------------
// Functions
//-----------------------------------------------------------------------------
// www.stackoverflow.com/questions/5149544/can-i-generate-a-random-number-inside-a-pixel-shader/
float random(float2 seed)
{
// irrationals for pseudo randomness
float2 i = float2(Gelfond, GelfondSchneider);
return frac(cos(dot(seed, i)) * 123456.0f);
}
// www.dinodini.wordpress.com/2010/04/05/normalized-tunable-sigmoid-functions/
float normalizedSigmoid(float n, float k)
{
// valid for n and k in range of -1.0 and 1.0
return (n - n * k) / (k - abs(n) * 2.0f * k + 1);
}
// www.iquilezles.org/www/articles/distfunctions/distfunctions.htm
float roundBox(float2 p, float2 b, float r)
{
return length(max(abs(p) - b + r, 0.0f)) - r;
}
//-----------------------------------------------------------------------------
// Distortion Vertex Shader
//-----------------------------------------------------------------------------
uniform float2 ScreenDims; // size of the window or fullscreen
uniform int ScreenCount;
uniform float2 TargetDims; // size of the target surface
uniform float2 TargetScale;
uniform float2 QuadDims; // size of the screen quad
VS_OUTPUT vs_main(VS_INPUT Input)
{
VS_OUTPUT Output = (VS_OUTPUT)0;
Output.Position = float4(Input.Position.xyz, 1.0f);
Output.Position.xy /= ScreenDims;
Output.Position.y = 1.0f - Output.Position.y; // flip y
Output.Position.xy -= 0.5f; // center
Output.Position.xy *= 2.0f; // zoom
Output.Color = Input.Color;
Output.TexCoord = Input.TexCoord;
Output.TexCoord += 0.5f / TargetDims; // half texel offset correction (DX9)
return Output;
}
//-----------------------------------------------------------------------------
// Distortion Pixel Shader
//-----------------------------------------------------------------------------
uniform float DistortionAmount = 0.0f; // k - quartic distortion coefficient
uniform float CubicDistortionAmount = 0.0f; // kcube - cubic distortion modifier
uniform float DistortCornerAmount = 0.0f;
uniform float RoundCornerAmount = 0.0f;
uniform float SmoothBorderAmount = 0.0f;
uniform float VignettingAmount = 0.0f;
uniform float ReflectionAmount = 0.0f;
uniform float3 LightReflectionColor = float3(1.0f, 0.90f, 0.80f); // color temperature 5.000 Kelvin
uniform bool SwapXY = false;
float GetNoiseFactor(float3 n, float random)
{
// smaller n become more noisy
return 1.0f + random * max(0.0f, 0.25f * pow(E, -8 * n));
}
float GetVignetteFactor(float2 coord, float amount)
{
float2 VignetteCoord = coord;
float VignetteLength = length(VignetteCoord);
float VignetteBlur = (amount * 0.75f) + 0.25;
// 0.5 full screen fitting circle
float VignetteRadius = 1.0f - (amount * 0.25f);
float Vignette = smoothstep(VignetteRadius, VignetteRadius - VignetteBlur, VignetteLength);
return saturate(Vignette);
}
float GetSpotAddend(float2 coord, float amount)
{
float2 SpotCoord = coord;
// upper right quadrant
float2 spotOffset = float2(-0.25f, 0.25f);
// normalized screen canvas ratio
float2 CanvasRatio = SwapXY
? float2(1.0f, QuadDims.x / QuadDims.y)
: float2(1.0f, QuadDims.y / QuadDims.x);
SpotCoord += spotOffset;
SpotCoord *= CanvasRatio;
float SpotBlur = amount;
// 0.5 full screen fitting circle
float SpotRadius = amount * 0.75f;
float Spot = smoothstep(SpotRadius, SpotRadius - SpotBlur, length(SpotCoord));
float SigmoidSpot = amount * normalizedSigmoid(Spot, 0.75);
// increase strength by 100%
SigmoidSpot = SigmoidSpot * 2.0f;
return saturate(SigmoidSpot);
}
float GetBoundsFactor(float2 coord, float2 bounds, float radiusAmount, float smoothAmount)
{
// reduce smooth amount down to radius amount
smoothAmount = min(smoothAmount, radiusAmount);
float range = min(bounds.x, bounds.y);
float amountMinimum = 1.0f / range;
float radius = range * max(radiusAmount, amountMinimum);
float smooth = 1.0f / (range * max(smoothAmount, amountMinimum * 2.0f));
// compute box
float box = roundBox(bounds * (coord * 2.0f), bounds, radius);
// apply smooth
box *= smooth;
box += 1.0f - pow(smooth * 0.5f, 0.5f);
float border = smoothstep(1.0f, 0.0f, box);
return saturate(border);
}
// www.francois-tarlier.com/blog/cubic-lens-distortion-shader/
float2 GetDistortedCoords(float2 centerCoord, float amount, float amountCube)
{
// lens distortion coefficient
float k = amount;
// cubic distortion value
float kcube = amountCube;
// compute cubic distortion factor
float r2 = centerCoord.x * centerCoord.x + centerCoord.y * centerCoord.y;
float f = kcube == 0.0f
? 1.0f + r2 * k
: 1.0f + r2 * (k + kcube * sqrt(r2));
// fit screen bounds
f /= 1.0f + amount * 0.25f + amountCube * 0.125f;
// apply cubic distortion factor
centerCoord *= f;
return centerCoord;
}
float2 GetTextureCoords(float2 coord, float distortionAmount, float cubicDistortionAmount)
{
// center coordinates
coord -= 0.5f;
// distort coordinates
coord = GetDistortedCoords(coord, distortionAmount, cubicDistortionAmount);
// un-center coordinates
coord += 0.5f;
return coord;
}
float2 GetQuadCoords(float2 coord, float2 scale, float distortionAmount, float cubicDistortionAmount)
{
// center coordinates
coord -= 0.5f;
// apply scale
coord *= scale;
// distort coordinates
coord = GetDistortedCoords(coord, distortionAmount, cubicDistortionAmount);
return coord;
}
float4 ps_main(PS_INPUT Input) : COLOR
{
// image distortion
float distortionAmount = DistortionAmount;
float cubicDistortionAmount = CubicDistortionAmount > 0.0f
? CubicDistortionAmount * 1.1f // cubic distortion need to be a little higher to compensate the quartic distortion
: CubicDistortionAmount * 1.2f; // negativ values even more
// corner distortion at least by the amount of the image distorition
float distortCornerAmount = max(DistortCornerAmount, DistortionAmount + CubicDistortionAmount);
float roundCornerAmount = RoundCornerAmount * 0.5f;
float smoothBorderAmount = SmoothBorderAmount * 0.5f;
float2 TexelDims = 1.0f / TargetDims;
// base-target dimensions (without oversampling)
float2 BaseTargetDims = TargetDims / TargetScale;
BaseTargetDims = SwapXY
? BaseTargetDims.yx
: BaseTargetDims.xy;
// base-target/quad difference scale
float2 BaseTargetQuadScale = ScreenCount == 1
? BaseTargetDims / QuadDims // keeps the coords inside of the quad bounds of a single screen
: 1.0f;
// Screen Texture Curvature
float2 BaseCoord = GetTextureCoords(Input.TexCoord, distortionAmount, cubicDistortionAmount);
// Screen Quad Curvature
float2 QuadCoord = GetQuadCoords(Input.TexCoord, BaseTargetQuadScale, distortCornerAmount, 0.0f);
// clip border
if (BaseCoord.x < 0.0f - TexelDims.x || BaseCoord.y < 0.0f - TexelDims.y ||
BaseCoord.x > 1.0f + TexelDims.x || BaseCoord.y > 1.0f + TexelDims.y)
{
return float4(0, 0, 0, 1);
}
// Color
float4 BaseColor = tex2D(DiffuseSampler, BaseCoord);
// Vignetting Simulation
float2 VignetteCoord = QuadCoord;
float VignetteFactor = GetVignetteFactor(VignetteCoord, VignettingAmount);
BaseColor.rgb *= VignetteFactor;
// Light Reflection Simulation
float2 SpotCoord = QuadCoord;
float SpotAddend = GetSpotAddend(SpotCoord, ReflectionAmount) * LightReflectionColor;
BaseColor.rgb += SpotAddend * GetNoiseFactor(SpotAddend, random(SpotCoord));
// Round Corners Simulation
float2 RoundCornerCoord = QuadCoord;
float2 RoundCornerBounds = ScreenCount == 1
? QuadDims // align corners to quad bounds of a single screen
: BaseTargetDims; // align corners to target bounds of multiple screens
RoundCornerBounds = SwapXY
? RoundCornerBounds.yx
: RoundCornerBounds.xy;
float roundCornerFactor = GetBoundsFactor(RoundCornerCoord, RoundCornerBounds, roundCornerAmount, smoothBorderAmount);
BaseColor.rgb *= roundCornerFactor;
return BaseColor;
}
//-----------------------------------------------------------------------------
// Distortion Technique
//-----------------------------------------------------------------------------
technique DefaultTechnique
{
pass Pass0
{
Lighting = FALSE;
VertexShader = compile vs_3_0 vs_main();
PixelShader = compile ps_3_0 ps_main();
}
}