1// PUBLIC DOMAIN CRT STYLED SCAN-LINE SHADER 2// 3// by Timothy Lottes 4// 5// This is more along the style of a really good CGA arcade monitor. 6// With RGB inputs instead of NTSC. 7// The shadow mask example has the mask rotated 90 degrees for less chromatic aberration. 8// 9// Left it unoptimized to show the theory behind the algorithm. 10// 11// It is an example what I personally would want as a display option for pixel art games. 12// Please take and use, change, or whatever. 13 14// Parameter lines go here: 15#pragma parameter hardScan "hardScan" -8.0 -20.0 0.0 1.0 16#pragma parameter hardPix "hardPix" -3.0 -20.0 0.0 1.0 17#pragma parameter warpX "warpX" 0.031 0.0 0.125 0.01 18#pragma parameter warpY "warpY" 0.041 0.0 0.125 0.01 19#pragma parameter maskDark "maskDark" 0.5 0.0 2.0 0.1 20#pragma parameter maskLight "maskLight" 1.5 0.0 2.0 0.1 21#pragma parameter scaleInLinearGamma "scaleInLinearGamma" 1.0 0.0 1.0 1.0 22#pragma parameter shadowMask "shadowMask" 3.0 0.0 4.0 1.0 23#pragma parameter brightBoost "brightness boost" 1.0 0.0 2.0 0.05 24#pragma parameter hardBloomPix "bloom-x soft" -1.5 -2.0 -0.5 0.1 25#pragma parameter hardBloomScan "bloom-y soft" -2.0 -4.0 -1.0 0.1 26#pragma parameter bloomAmount "bloom ammount" 0.15 0.0 1.0 0.05 27#pragma parameter shape "filter kernel shape" 2.0 0.0 10.0 0.05 28 29#if defined(VERTEX) 30 31#if __VERSION__ >= 130 32#define COMPAT_VARYING out 33#define COMPAT_ATTRIBUTE in 34#define COMPAT_TEXTURE texture 35#else 36#define COMPAT_VARYING varying 37#define COMPAT_ATTRIBUTE attribute 38#define COMPAT_TEXTURE texture2D 39#endif 40 41#ifdef GL_ES 42#define COMPAT_PRECISION mediump 43#else 44#define COMPAT_PRECISION 45#endif 46 47COMPAT_ATTRIBUTE vec4 VertexCoord; 48COMPAT_ATTRIBUTE vec4 COLOR; 49COMPAT_ATTRIBUTE vec4 TexCoord; 50COMPAT_VARYING vec4 COL0; 51COMPAT_VARYING vec4 TEX0; 52 53uniform mat4 MVPMatrix; 54uniform COMPAT_PRECISION int FrameDirection; 55uniform COMPAT_PRECISION int FrameCount; 56uniform COMPAT_PRECISION vec2 OutputSize; 57uniform COMPAT_PRECISION vec2 TextureSize; 58uniform COMPAT_PRECISION vec2 InputSize; 59 60// vertex compatibility #defines 61#define vTexCoord TEX0.xy 62#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize 63#define outsize vec4(OutputSize, 1.0 / OutputSize) 64 65void main() 66{ 67 gl_Position = MVPMatrix * VertexCoord; 68 TEX0.xy = TexCoord.xy; 69} 70 71#elif defined(FRAGMENT) 72 73#if __VERSION__ >= 130 74#define COMPAT_VARYING in 75#define COMPAT_TEXTURE texture 76out vec4 FragColor; 77#else 78#define COMPAT_VARYING varying 79#define FragColor gl_FragColor 80#define COMPAT_TEXTURE texture2D 81#endif 82 83#ifdef GL_ES 84#ifdef GL_FRAGMENT_PRECISION_HIGH 85precision highp float; 86#else 87precision mediump float; 88#endif 89#define COMPAT_PRECISION mediump 90#else 91#define COMPAT_PRECISION 92#endif 93 94uniform COMPAT_PRECISION int FrameDirection; 95uniform COMPAT_PRECISION int FrameCount; 96uniform COMPAT_PRECISION vec2 OutputSize; 97uniform COMPAT_PRECISION vec2 TextureSize; 98uniform COMPAT_PRECISION vec2 InputSize; 99uniform sampler2D Texture; 100COMPAT_VARYING vec4 TEX0; 101 102// fragment compatibility #defines 103#define Source Texture 104#define vTexCoord TEX0.xy 105 106#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize 107#define outsize vec4(OutputSize, 1.0 / OutputSize) 108 109#ifdef PARAMETER_UNIFORM 110// All parameter floats need to have COMPAT_PRECISION in front of them 111uniform COMPAT_PRECISION float hardScan; 112uniform COMPAT_PRECISION float hardPix; 113uniform COMPAT_PRECISION float warpX; 114uniform COMPAT_PRECISION float warpY; 115uniform COMPAT_PRECISION float maskDark; 116uniform COMPAT_PRECISION float maskLight; 117uniform COMPAT_PRECISION float scaleInLinearGamma; 118uniform COMPAT_PRECISION float shadowMask; 119uniform COMPAT_PRECISION float brightBoost; 120uniform COMPAT_PRECISION float hardBloomPix; 121uniform COMPAT_PRECISION float hardBloomScan; 122uniform COMPAT_PRECISION float bloomAmount; 123uniform COMPAT_PRECISION float shape; 124#else 125#define hardScan -8.0 126#define hardPix -3.0 127#define warpX 0.031 128#define warpY 0.041 129#define maskDark 0.5 130#define maskLight 1.5 131#define scaleInLinearGamma 1.0 132#define shadowMask 3.0 133#define brightBoost 1.0 134#define hardBloomPix -1.5 135#define hardBloomScan -2.0 136#define bloomAmount 0.15 137#define shape 2.0 138#endif 139 140//Uncomment to reduce instructions with simpler linearization 141//(fixes HD3000 Sandy Bridge IGP) 142//#define SIMPLE_LINEAR_GAMMA 143#define DO_BLOOM 144 145// ------------- // 146 147// sRGB to Linear. 148// Assuming using sRGB typed textures this should not be needed. 149#ifdef SIMPLE_LINEAR_GAMMA 150float ToLinear1(float c) 151{ 152 return c; 153} 154vec3 ToLinear(vec3 c) 155{ 156 return c; 157} 158vec3 ToSrgb(vec3 c) 159{ 160 return pow(c, vec3(1.0 / 2.2)); 161} 162#else 163float ToLinear1(float c) 164{ 165 if (scaleInLinearGamma == 0.) 166 return c; 167 168 return(c<=0.04045) ? c/12.92 : pow((c + 0.055)/1.055, 2.4); 169} 170 171vec3 ToLinear(vec3 c) 172{ 173 if (scaleInLinearGamma==0.) 174 return c; 175 176 return vec3(ToLinear1(c.r), ToLinear1(c.g), ToLinear1(c.b)); 177} 178 179// Linear to sRGB. 180// Assuming using sRGB typed textures this should not be needed. 181float ToSrgb1(float c) 182{ 183 if (scaleInLinearGamma == 0.) 184 return c; 185 186 return(c<0.0031308 ? c*12.92 : 1.055*pow(c, 0.41666) - 0.055); 187} 188 189vec3 ToSrgb(vec3 c) 190{ 191 if (scaleInLinearGamma == 0.) 192 return c; 193 194 return vec3(ToSrgb1(c.r), ToSrgb1(c.g), ToSrgb1(c.b)); 195} 196#endif 197 198// Nearest emulated sample given floating point position and texel offset. 199// Also zero's off screen. 200vec3 Fetch(vec2 pos,vec2 off){ 201 pos=(floor(pos*SourceSize.xy+off)+vec2(0.5,0.5))/SourceSize.xy; 202#ifdef SIMPLE_LINEAR_GAMMA 203 return ToLinear(brightBoost * pow(COMPAT_TEXTURE(Source,pos.xy).rgb, vec3(2.2))); 204#else 205 return ToLinear(brightBoost * COMPAT_TEXTURE(Source,pos.xy).rgb); 206#endif 207} 208 209// Distance in emulated pixels to nearest texel. 210vec2 Dist(vec2 pos) 211{ 212 pos = pos*SourceSize.xy; 213 214 return -((pos - floor(pos)) - vec2(0.5)); 215} 216 217// 1D Gaussian. 218float Gaus(float pos, float scale) 219{ 220 return exp2(scale*pow(abs(pos), shape)); 221} 222 223// 3-tap Gaussian filter along horz line. 224vec3 Horz3(vec2 pos, float off) 225{ 226 vec3 b = Fetch(pos, vec2(-1.0, off)); 227 vec3 c = Fetch(pos, vec2( 0.0, off)); 228 vec3 d = Fetch(pos, vec2( 1.0, off)); 229 float dst = Dist(pos).x; 230 231 // Convert distance to weight. 232 float scale = hardPix; 233 float wb = Gaus(dst-1.0,scale); 234 float wc = Gaus(dst+0.0,scale); 235 float wd = Gaus(dst+1.0,scale); 236 237 // Return filtered sample. 238 return (b*wb+c*wc+d*wd)/(wb+wc+wd); 239} 240 241// 5-tap Gaussian filter along horz line. 242vec3 Horz5(vec2 pos,float off){ 243 vec3 a = Fetch(pos,vec2(-2.0, off)); 244 vec3 b = Fetch(pos,vec2(-1.0, off)); 245 vec3 c = Fetch(pos,vec2( 0.0, off)); 246 vec3 d = Fetch(pos,vec2( 1.0, off)); 247 vec3 e = Fetch(pos,vec2( 2.0, off)); 248 249 float dst = Dist(pos).x; 250 // Convert distance to weight. 251 float scale = hardPix; 252 float wa = Gaus(dst - 2.0, scale); 253 float wb = Gaus(dst - 1.0, scale); 254 float wc = Gaus(dst + 0.0, scale); 255 float wd = Gaus(dst + 1.0, scale); 256 float we = Gaus(dst + 2.0, scale); 257 258 // Return filtered sample. 259 return (a*wa+b*wb+c*wc+d*wd+e*we)/(wa+wb+wc+wd+we); 260} 261 262// 7-tap Gaussian filter along horz line. 263vec3 Horz7(vec2 pos,float off) 264{ 265 vec3 a = Fetch(pos, vec2(-3.0, off)); 266 vec3 b = Fetch(pos, vec2(-2.0, off)); 267 vec3 c = Fetch(pos, vec2(-1.0, off)); 268 vec3 d = Fetch(pos, vec2( 0.0, off)); 269 vec3 e = Fetch(pos, vec2( 1.0, off)); 270 vec3 f = Fetch(pos, vec2( 2.0, off)); 271 vec3 g = Fetch(pos, vec2( 3.0, off)); 272 273 float dst = Dist(pos).x; 274 // Convert distance to weight. 275 float scale = hardBloomPix; 276 float wa = Gaus(dst - 3.0, scale); 277 float wb = Gaus(dst - 2.0, scale); 278 float wc = Gaus(dst - 1.0, scale); 279 float wd = Gaus(dst + 0.0, scale); 280 float we = Gaus(dst + 1.0, scale); 281 float wf = Gaus(dst + 2.0, scale); 282 float wg = Gaus(dst + 3.0, scale); 283 284 // Return filtered sample. 285 return (a*wa+b*wb+c*wc+d*wd+e*we+f*wf+g*wg)/(wa+wb+wc+wd+we+wf+wg); 286} 287 288// Return scanline weight. 289float Scan(vec2 pos, float off) 290{ 291 float dst = Dist(pos).y; 292 293 return Gaus(dst + off, hardScan); 294} 295 296// Return scanline weight for bloom. 297float BloomScan(vec2 pos, float off) 298{ 299 float dst = Dist(pos).y; 300 301 return Gaus(dst + off, hardBloomScan); 302} 303 304// Allow nearest three lines to effect pixel. 305vec3 Tri(vec2 pos) 306{ 307 vec3 a = Horz3(pos,-1.0); 308 vec3 b = Horz5(pos, 0.0); 309 vec3 c = Horz3(pos, 1.0); 310 311 float wa = Scan(pos,-1.0); 312 float wb = Scan(pos, 0.0); 313 float wc = Scan(pos, 1.0); 314 315 return a*wa + b*wb + c*wc; 316} 317 318// Small bloom. 319vec3 Bloom(vec2 pos) 320{ 321 vec3 a = Horz5(pos,-2.0); 322 vec3 b = Horz7(pos,-1.0); 323 vec3 c = Horz7(pos, 0.0); 324 vec3 d = Horz7(pos, 1.0); 325 vec3 e = Horz5(pos, 2.0); 326 327 float wa = BloomScan(pos,-2.0); 328 float wb = BloomScan(pos,-1.0); 329 float wc = BloomScan(pos, 0.0); 330 float wd = BloomScan(pos, 1.0); 331 float we = BloomScan(pos, 2.0); 332 333 return a*wa+b*wb+c*wc+d*wd+e*we; 334} 335 336// Distortion of scanlines, and end of screen alpha. 337vec2 Warp(vec2 pos) 338{ 339 pos = pos*2.0-1.0; 340 pos *= vec2(1.0 + (pos.y*pos.y)*warpX, 1.0 + (pos.x*pos.x)*warpY); 341 342 return pos*0.5 + 0.5; 343} 344 345// Shadow mask. 346vec3 Mask(vec2 pos) 347{ 348 vec3 mask = vec3(maskDark, maskDark, maskDark); 349 350 // Very compressed TV style shadow mask. 351 if (shadowMask == 1.0) 352 { 353 float line = maskLight; 354 float odd = 0.0; 355 356 if (fract(pos.x*0.166666666) < 0.5) odd = 1.0; 357 if (fract((pos.y + odd) * 0.5) < 0.5) line = maskDark; 358 359 pos.x = fract(pos.x*0.333333333); 360 361 if (pos.x < 0.333) mask.r = maskLight; 362 else if (pos.x < 0.666) mask.g = maskLight; 363 else mask.b = maskLight; 364 mask*=line; 365 } 366 367 // Aperture-grille. 368 else if (shadowMask == 2.0) 369 { 370 pos.x = fract(pos.x*0.333333333); 371 372 if (pos.x < 0.333) mask.r = maskLight; 373 else if (pos.x < 0.666) mask.g = maskLight; 374 else mask.b = maskLight; 375 } 376 377 // Stretched VGA style shadow mask (same as prior shaders). 378 else if (shadowMask == 3.0) 379 { 380 pos.x += pos.y*3.0; 381 pos.x = fract(pos.x*0.166666666); 382 383 if (pos.x < 0.333) mask.r = maskLight; 384 else if (pos.x < 0.666) mask.g = maskLight; 385 else mask.b = maskLight; 386 } 387 388 // VGA style shadow mask. 389 else if (shadowMask == 4.0) 390 { 391 pos.xy = floor(pos.xy*vec2(1.0, 0.5)); 392 pos.x += pos.y*3.0; 393 pos.x = fract(pos.x*0.166666666); 394 395 if (pos.x < 0.333) mask.r = maskLight; 396 else if (pos.x < 0.666) mask.g = maskLight; 397 else mask.b = maskLight; 398 } 399 400 return mask; 401} 402 403void main() 404{ 405 vec2 pos = Warp(TEX0.xy*(TextureSize.xy/InputSize.xy))*(InputSize.xy/TextureSize.xy); 406 vec3 outColor = Tri(pos); 407 408#ifdef DO_BLOOM 409 //Add Bloom 410 outColor.rgb += Bloom(pos)*bloomAmount; 411#endif 412 413 if (shadowMask > 0.0) 414 outColor.rgb *= Mask(gl_FragCoord.xy * 1.000001); 415 416#ifdef GL_ES /* TODO/FIXME - hacky clamp fix */ 417 vec2 bordertest = (pos); 418 if ( bordertest.x > 0.0001 && bordertest.x < 0.9999 && bordertest.y > 0.0001 && bordertest.y < 0.9999) 419 outColor.rgb = outColor.rgb; 420 else 421 outColor.rgb = vec3(0.0); 422#endif 423 FragColor = vec4(ToSrgb(outColor.rgb), 1.0); 424} 425#endif 426