/* * CRT shader * * Copyright (C) 2010, 2011 cgwg, Themaister,DOLLS, gulikoza * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. * * (cgwg gave their consent to have the original version of this shader * distributed under the GPL in this message: * * http://board.byuu.org/viewtopic.php?p=26075#p26075 * * "Feel free to distribute my shaders under the GPL. After all, the * barrel distortion code was taken from the Curvature shader, which is * under the GPL." * * Direct3D port by gulikoza at users.sourceforge.net * */ #include "Scaling.inc" // The name of this effect string name : NAME = "CRTFX"; float scaling : SCALING = 1.0; // Comment the next line to disable interpolation in linear gamma (and gain speed). #define LINEAR_PROCESSING // Compensate for 16-235 level range as per Rec. 601. #define REF_LEVELS // Enable screen curvature. #define CURVATURE // Controls the intensity of the barrel distortion used to emulate the // curvature of a CRT. 0.0 is perfectly flat, 1.0 is annoyingly // distorted, higher values are increasingly ridiculous. #define distortion 0.05 // Simulate a CRT gamma of 2.4. #define inputGamma 2.4 // Compensate for the standard sRGB gamma of 2.2. #define outputGamma 2.2 // Macros. #define FIX(c) max(abs(c), 1e-5); #define PI 3.141592653589 #ifdef REF_LEVELS # define LEVELS(c) max((c - 16.0 / 255.0) * 255.0 / (235.0 - 16.0), 0.0) #else # define LEVELS(c) c #endif #ifdef LINEAR_PROCESSING # define TEX2D(c) pow(LEVELS(tex2D(SourceBorderSampler, (c))), inputGamma) #else # define TEX2D(c) LEVELS(tex2D(SourceBorderSampler, (c))) #endif // // Techniques // // combineTechnique: Final combine steps. Outputs to destination frame buffer string combineTechique : COMBINETECHNIQUE = "CRTFX"; // preprocessTechnique: PreProcessing steps. Outputs to WorkingTexture //string preprocessTechique : PREPROCESSTECHNIQUE = ""; struct VS_OUTPUT_PRODUCT { float4 Position : POSITION; float2 pixel0 : TEXCOORD0; float2 pixel1 : TEXCOORD1; float2 abspos : TEXCOORD2; }; sampler SourceBorderSampler = sampler_state { Texture = (SourceTexture); MinFilter = POINT; MagFilter = POINT; MipFilter = NONE; AddressU = Border; AddressV = Border; SRGBTEXTURE = FALSE; }; // vertex shader VS_OUTPUT_PRODUCT VS_Product( float3 Position : POSITION, float2 TexCoord : TEXCOORD0) { VS_OUTPUT_PRODUCT Out = (VS_OUTPUT_PRODUCT)0; // Do the standard vertex processing. Out.Position = mul(half4(Position, 1), WorldViewProjection); // Precalculate a bunch of useful values we'll need in the fragment // shader. // Texture coords. Out.pixel0 = TexCoord; // The size of one texel, in texture-coordinates. Out.pixel1 = TexelSize; // Resulting X pixel-coordinate of the pixel we're drawing. // Assumes (-0.5, 0.5) quad and output size in World matrix // as currently done in DOSBox D3D patch Out.abspos = float2((Position.x + 0.5) * World._11, (Position.y - 0.5) * (-World._22)); return Out; } // Apply radial distortion to the given coordinate. float2 radialDistortion(float2 coord, float2 pos) { pos /= float2(World._11, World._22); float2 cc = pos - 0.5; float dist = dot(cc, cc) * distortion; return coord * (pos + cc * (1.0 + dist) * dist) / pos; } // Calculate the influence of a scanline on the current pixel. // // 'distance' is the distance in texture coordinates from the current // pixel to the scanline in question. // 'color' is the colour of the scanline at the horizontal location of // the current pixel. float4 scanlineWeights(float distance, float4 color) { // The "width" of the scanline beam is set as 2*(1 + x^4) for // each RGB channel. float4 wid = 2.0 + 2.0 * pow(color, 4.0); // The "weights" lines basically specify the formula that gives // you the profile of the beam, i.e. the intensity as // a function of distance from the vertical center of the // scanline. In this case, it is gaussian if width=2, and // becomes nongaussian for larger widths. Ideally this should // be normalized so that the integral across the beam is // independent of its width. That is, for a narrower beam // "weights" should have a higher peak at the center of the // scanline than for a wider beam. float4 weights = distance / 0.3; return 1.4 * exp(-pow(weights * rsqrt(0.5 * wid), wid)) / (0.6 + 0.2 * wid); } half4 PS_Product ( in VS_OUTPUT_PRODUCT input ) : COLOR { // Here's a helpful diagram to keep in mind while trying to // understand the code: // // | | | | | // ------------------------------- // | | | | | // | 01 | 11 | 21 | 31 | <-- current scanline // | | @ | | | // ------------------------------- // | | | | | // | 02 | 12 | 22 | 32 | <-- next scanline // | | | | | // ------------------------------- // | | | | | // // Each character-cell represents a pixel on the output // surface, "@" represents the current pixel (always somewhere // in the bottom half of the current scan-line, or the top-half // of the next scanline). The grid of lines represents the // edges of the texels of the underlying texture. // Texture coordinates of the texel containing the active pixel. #ifdef CURVATURE float2 xy = radialDistortion(input.pixel0, input.abspos); #else float2 xy = input.pixel0; #endif // Of all the pixels that are mapped onto the texel we are // currently rendering, which pixel are we currently rendering? float2 ratio_scale = xy * SourceDims - 0.5; float2 uv_ratio = frac(ratio_scale); // Snap to the center of the underlying texel. xy = (floor(ratio_scale) + 0.5) / SourceDims; // Calculate Lanczos scaling coefficients describing the effect // of various neighbour texels in a scanline on the current // pixel. float4 coeffs = PI * float4(1.0 + uv_ratio.x, uv_ratio.x, 1.0 - uv_ratio.x, 2.0 - uv_ratio.x); // Prevent division by zero. coeffs = FIX(coeffs); // Lanczos2 kernel. coeffs = 2.0 * sin(coeffs) * sin(coeffs / 2.0) / (coeffs * coeffs); // Normalize. coeffs /= dot(coeffs, 1.0); // Calculate the effective colour of the current and next // scanlines at the horizontal location of the current pixel, // using the Lanczos coefficients above. float4 col = clamp( mul(coeffs, float4x4( TEX2D(xy + float2(-input.pixel1.r, 0.0)), TEX2D(xy), TEX2D(xy + float2(input.pixel1.x, 0.0)), TEX2D(xy + float2(2.0 * input.pixel1.x, 0.0)) )), 0.0, 1.0); float4 col2 = clamp( mul(coeffs, float4x4( TEX2D(xy + float2(-input.pixel1.x, input.pixel1.y)), TEX2D(xy + float2(0.0, input.pixel1.y)), TEX2D(xy + input.pixel1), TEX2D(xy + float2(2.0 * input.pixel1.x, input.pixel1.y)) )), 0.0, 1.0); #ifndef LINEAR_PROCESSING col = pow(col , inputGamma); col2 = pow(col2, inputGamma); #endif // Calculate the influence of the current and next scanlines on // the current pixel. float4 weights = scanlineWeights(uv_ratio.y, col); float4 weights2 = scanlineWeights(1.0 - uv_ratio.y, col2); float3 mul_res = (col * weights + col2 * weights2).rgb; // dot-mask emulation: // Output pixels are alternately tinted green and magenta. float3 dotMaskWeights = lerp( float3(1.0, 0.7, 1.0), float3(0.7, 1.0, 0.7), floor(input.abspos.x % 2.0) ); mul_res *= dotMaskWeights; // Convert the image gamma for display on our output device. mul_res = pow(mul_res, 1.0 / outputGamma); // Color the texel. return half4(mul_res, 1.0); } technique CRTFX { pass P0 { // shaders VertexShader = compile vs_3_0 VS_Product(); PixelShader = compile ps_3_0 PS_Product(); AlphaBlendEnable = FALSE; ColorWriteEnable = RED|GREEN|BLUE|ALPHA; SRGBWRITEENABLE = FALSE; } }