crt-lottes.glsl (9344B)
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 /* 15 [configuration] 16 17 [OptionRangeFloat] 18 GUIName = Scanline Weight 19 OptionName = hardScan 20 MinValue = -20.0 21 MaxValue = 0.0 22 StepAmount = 1.0 23 DefaultValue = -8.0 24 25 [OptionRangeFloat] 26 GUIName = Scanline Scale 27 OptionName = hardPix 28 MinValue = -20.0 29 MaxValue = 0.0 30 StepAmount = 1.0 31 DefaultValue = -3.0 32 33 [OptionRangeFloat] 34 GUIName = Screen Warp X 35 OptionName = warpX 36 MinValue = 0.0 37 MaxValue = 0.125 38 StepAmount = 0.01 39 DefaultValue = 0.031 40 41 [OptionRangeFloat] 42 GUIName = Screen Warp Y 43 OptionName = warpY 44 MinValue = 0.0 45 MaxValue = 0.125 46 StepAmount = 0.01 47 DefaultValue = 0.041 48 49 [OptionRangeFloat] 50 GUIName = Mask Dark 51 OptionName = maskDark 52 MinValue = 0.0 53 MaxValue = 2.0 54 StepAmount = 0.1 55 DefaultValue = 0.5 56 57 [OptionRangeFloat] 58 GUIName = Mask Light 59 OptionName = maskLight 60 MinValue = 0.0 61 MaxValue = 2.0 62 StepAmount = 0.1 63 DefaultValue = 1.5 64 65 [OptionRangeInteger] 66 GUIName = Shadow Mask Type 67 OptionName = shadowMask 68 MinValue = 0 69 MaxValue = 4 70 StepAmount = 1 71 DefaultValue = 3 72 73 [OptionRangeFloat] 74 GUIName = Brightess Boost 75 OptionName = brightBoost 76 MinValue = 0.0 77 MaxValue = 2.0 78 StepAmount = 0.05 79 DefaultValue = 1.0 80 81 [OptionRangeFloat] 82 GUIName = Bloom Soft X 83 OptionName = hardBloomPix 84 MinValue = -2.0 85 MaxValue = -0.5 86 StepAmount = 0.1 87 DefaultValue = -1.5 88 89 [OptionRangeFloat] 90 GUIName = Bloom Soft Y 91 OptionName = hardBloomScan 92 MinValue = -4.0 93 MaxValue = -1.0 94 StepAmount = 0.1 95 DefaultValue = -2.0 96 97 [OptionRangeFloat] 98 GUIName = Bloom Amount 99 OptionName = bloomAmount 100 MinValue = 0.0 101 MaxValue = 1.0 102 StepAmount = 0.05 103 DefaultValue = 0.15 104 105 [OptionRangeFloat] 106 GUIName = Filter Kernel Shape 107 OptionName = shape 108 MinValue = 0.0 109 MaxValue = 10.0 110 StepAmount = 0.05 111 DefaultValue = 2.0 112 113 [/configuration] 114 */ 115 116 //Uncomment to reduce instructions with simpler linearization 117 //(fixes HD3000 Sandy Bridge IGP) 118 #define SIMPLE_LINEAR_GAMMA 119 #define DO_BLOOM 120 121 // ------------- // 122 123 // sRGB to Linear. 124 // Assuming using sRGB typed textures this should not be needed. 125 #ifdef SIMPLE_LINEAR_GAMMA 126 float ToLinear1(float c) 127 { 128 return c; 129 } 130 float3 ToLinear(float3 c) 131 { 132 return c; 133 } 134 float3 ToSrgb(float3 c) 135 { 136 return pow(c, float3(1.0 / 2.2, 1.0 / 2.2, 1.0 / 2.2)); 137 } 138 #else 139 float ToLinear1(float c) 140 { 141 return(c<=0.04045) ? c/12.92 : pow((c + 0.055)/1.055, 2.4); 142 } 143 144 float3 ToLinear(float3 c) 145 { 146 return float3(ToLinear1(c.r), ToLinear1(c.g), ToLinear1(c.b)); 147 } 148 149 // Linear to sRGB. 150 // Assuming using sRGB typed textures this should not be needed. 151 float ToSrgb1(float c) 152 { 153 return(c<0.0031308 ? c*12.92 : 1.055*pow(c, 0.41666) - 0.055); 154 } 155 156 float3 ToSrgb(float3 c) 157 { 158 return float3(ToSrgb1(c.r), ToSrgb1(c.g), ToSrgb1(c.b)); 159 } 160 #endif 161 162 // Nearest emulated sample given floating point position and texel offset. 163 // Also zero's off screen. 164 float3 Fetch(float2 pos,float2 off){ 165 pos=(floor(pos*GetResolution()+off)+float2(0.5,0.5))*GetInvResolution(); 166 #ifdef SIMPLE_LINEAR_GAMMA 167 return ToLinear(GetOption(brightBoost) * pow(SampleLocation(pos.xy).rgb, float3(2.2, 2.2, 2.2))); 168 #else 169 return ToLinear(GetOption(brightBoost) * SampleLocation(pos.xy).rgb); 170 #endif 171 } 172 173 // Distance in emulated pixels to nearest texel. 174 float2 Dist(float2 pos) 175 { 176 pos = pos * (GetNativeSize() * GetWindowToViewportRatio()); 177 178 return -((pos - floor(pos)) - float2(0.5, 0.5)); 179 } 180 181 // 1D Gaussian. 182 float Gaus(float pos, float scale) 183 { 184 return exp2(scale*pow(abs(pos), GetOption(shape))); 185 } 186 187 // 3-tap Gaussian filter along horz line. 188 float3 Horz3(float2 pos, float off) 189 { 190 float3 b = Fetch(pos, float2(-1.0, off)); 191 float3 c = Fetch(pos, float2( 0.0, off)); 192 float3 d = Fetch(pos, float2( 1.0, off)); 193 float dst = Dist(pos).x; 194 195 // Convert distance to weight. 196 float scale = GetOption(hardPix); 197 float wb = Gaus(dst-1.0,scale); 198 float wc = Gaus(dst+0.0,scale); 199 float wd = Gaus(dst+1.0,scale); 200 201 // Return filtered sample. 202 return (b*wb+c*wc+d*wd)/(wb+wc+wd); 203 } 204 205 // 5-tap Gaussian filter along horz line. 206 float3 Horz5(float2 pos,float off){ 207 float3 a = Fetch(pos,float2(-2.0, off)); 208 float3 b = Fetch(pos,float2(-1.0, off)); 209 float3 c = Fetch(pos,float2( 0.0, off)); 210 float3 d = Fetch(pos,float2( 1.0, off)); 211 float3 e = Fetch(pos,float2( 2.0, off)); 212 213 float dst = Dist(pos).x; 214 // Convert distance to weight. 215 float scale = GetOption(hardPix); 216 float wa = Gaus(dst - 2.0, scale); 217 float wb = Gaus(dst - 1.0, scale); 218 float wc = Gaus(dst + 0.0, scale); 219 float wd = Gaus(dst + 1.0, scale); 220 float we = Gaus(dst + 2.0, scale); 221 222 // Return filtered sample. 223 return (a*wa+b*wb+c*wc+d*wd+e*we)/(wa+wb+wc+wd+we); 224 } 225 226 // 7-tap Gaussian filter along horz line. 227 float3 Horz7(float2 pos,float off) 228 { 229 float3 a = Fetch(pos, float2(-3.0, off)); 230 float3 b = Fetch(pos, float2(-2.0, off)); 231 float3 c = Fetch(pos, float2(-1.0, off)); 232 float3 d = Fetch(pos, float2( 0.0, off)); 233 float3 e = Fetch(pos, float2( 1.0, off)); 234 float3 f = Fetch(pos, float2( 2.0, off)); 235 float3 g = Fetch(pos, float2( 3.0, off)); 236 237 float dst = Dist(pos).x; 238 // Convert distance to weight. 239 float scale = GetOption(hardBloomPix); 240 float wa = Gaus(dst - 3.0, scale); 241 float wb = Gaus(dst - 2.0, scale); 242 float wc = Gaus(dst - 1.0, scale); 243 float wd = Gaus(dst + 0.0, scale); 244 float we = Gaus(dst + 1.0, scale); 245 float wf = Gaus(dst + 2.0, scale); 246 float wg = Gaus(dst + 3.0, scale); 247 248 // Return filtered sample. 249 return (a*wa+b*wb+c*wc+d*wd+e*we+f*wf+g*wg)/(wa+wb+wc+wd+we+wf+wg); 250 } 251 252 // Return scanline weight. 253 float Scan(float2 pos, float off) 254 { 255 float dst = Dist(pos).y; 256 257 return Gaus(dst + off, GetOption(hardScan)); 258 } 259 260 // Return scanline weight for bloom. 261 float BloomScan(float2 pos, float off) 262 { 263 float dst = Dist(pos).y; 264 265 return Gaus(dst + off, GetOption(hardBloomScan)); 266 } 267 268 // Allow nearest three lines to effect pixel. 269 float3 Tri(float2 pos) 270 { 271 float3 a = Horz3(pos,-1.0); 272 float3 b = Horz5(pos, 0.0); 273 float3 c = Horz3(pos, 1.0); 274 275 float wa = Scan(pos,-1.0); 276 float wb = Scan(pos, 0.0); 277 float wc = Scan(pos, 1.0); 278 279 return a*wa + b*wb + c*wc; 280 } 281 282 // Small bloom. 283 float3 Bloom(float2 pos) 284 { 285 float3 a = Horz5(pos,-2.0); 286 float3 b = Horz7(pos,-1.0); 287 float3 c = Horz7(pos, 0.0); 288 float3 d = Horz7(pos, 1.0); 289 float3 e = Horz5(pos, 2.0); 290 291 float wa = BloomScan(pos,-2.0); 292 float wb = BloomScan(pos,-1.0); 293 float wc = BloomScan(pos, 0.0); 294 float wd = BloomScan(pos, 1.0); 295 float we = BloomScan(pos, 2.0); 296 297 return a*wa+b*wb+c*wc+d*wd+e*we; 298 } 299 300 // Distortion of scanlines, and end of screen alpha. 301 float2 Warp(float2 pos) 302 { 303 pos = pos*2.0-1.0; 304 pos *= float2(1.0 + (pos.y*pos.y)*GetOption(warpX), 1.0 + (pos.x*pos.x)*GetOption(warpY)); 305 306 return pos*0.5 + 0.5; 307 } 308 309 // Shadow mask. 310 float3 Mask(float2 pos) 311 { 312 float3 mask = float3(GetOption(maskDark), GetOption(maskDark), GetOption(maskDark)); 313 314 // Very compressed TV style shadow mask. 315 if (GetOption(shadowMask) == 1) 316 { 317 float line_ = GetOption(maskLight); 318 float odd = 0.0; 319 320 if (fract(pos.x*0.166666666) < 0.5) odd = 1.0; 321 if (fract((pos.y + odd) * 0.5) < 0.5) line_ = GetOption(maskDark); 322 323 pos.x = fract(pos.x*0.333333333); 324 325 if (pos.x < 0.333) mask.r = GetOption(maskLight); 326 else if (pos.x < 0.666) mask.g = GetOption(maskLight); 327 else mask.b = GetOption(maskLight); 328 mask*=line_; 329 } 330 331 // Aperture-grille. 332 else if (GetOption(shadowMask) == 2) 333 { 334 pos.x = fract(pos.x*0.333333333); 335 336 if (pos.x < 0.333) mask.r = GetOption(maskLight); 337 else if (pos.x < 0.666) mask.g = GetOption(maskLight); 338 else mask.b = GetOption(maskLight); 339 } 340 341 // Stretched VGA style shadow mask (same as prior shaders). 342 else if (GetOption(shadowMask) == 3) 343 { 344 pos.x += pos.y*3.0; 345 pos.x = fract(pos.x*0.166666666); 346 347 if (pos.x < 0.333) mask.r = GetOption(maskLight); 348 else if (pos.x < 0.666) mask.g = GetOption(maskLight); 349 else mask.b = GetOption(maskLight); 350 } 351 352 // VGA style shadow mask. 353 else if (GetOption(shadowMask) == 4) 354 { 355 pos.xy = floor(pos.xy*float2(1.0, 0.5)); 356 pos.x += pos.y*3.0; 357 pos.x = fract(pos.x*0.166666666); 358 359 if (pos.x < 0.333) mask.r = GetOption(maskLight); 360 else if (pos.x < 0.666) mask.g = GetOption(maskLight); 361 else mask.b = GetOption(maskLight); 362 } 363 364 return mask; 365 } 366 367 void main() 368 { 369 float2 pos = Warp(GetCoordinates()); 370 float3 outColor = Tri(pos); 371 372 #ifdef DO_BLOOM 373 //Add Bloom 374 outColor.rgb += Bloom(pos)*GetOption(bloomAmount); 375 #endif 376 377 if (GetOption(shadowMask) > 0) 378 outColor.rgb *= Mask(gl_FragCoord.xy * 1.000001); 379 380 SetOutput(float4(ToSrgb(outColor.rgb), 1.0)); 381 }