mirror of
https://github.com/italicsjenga/slang-shaders.git
synced 2024-11-23 00:01:31 +11:00
330 lines
10 KiB
Plaintext
330 lines
10 KiB
Plaintext
#version 450
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layout(push_constant) uniform Push
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{
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vec4 SourceSize;
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vec4 OriginalSize;
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vec4 OutputSize;
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uint FrameCount;
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float CURVATURE_toggle, CRTgamma, overscan_x, overscan_y, distance, radius, tiltangle_x, tiltangle_y, cornersize, cornersmooth;
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} params;
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#pragma parameter CURVATURE_toggle "Curvature Toggle" 1.0 0.0 1.0 1.0
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#define CURVATURE bool(params.CURVATURE_toggle)
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// gamma of simulated CRT
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#pragma parameter CRTgamma "CRT Gamma" 2.4 1.0 4.0 0.05
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#define CRTgamma params.CRTgamma
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// overscan (e.g. 1.02 for 2% overscan)
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#pragma parameter overscan_x "Overscan X" 1.0 0.0 2.0 0.01
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#pragma parameter overscan_y "Overscan Y" 1.0 0.0 2.0 0.01
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#define overscan vec2(params.overscan_x, params.overscan_y)
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#pragma parameter distance "Viewing Distance" 2.0 0.1 5.0 0.1
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#define distance params.distance
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// radius of curvature
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#pragma parameter radius "Curvature Radius" 2.0 0.1 5.0 0.1
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#define radius params.radius
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// tilt angle in radians
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// (behavior might be a bit wrong if both components are nonzero)
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#pragma parameter tiltangle_x "Tilt Angle X" 0.0 -1.0 1.0 0.05
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#pragma parameter tiltangle_y "Tilt Angle Y" 0.0 -1.0 1.0 0.05
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#define tiltangle vec2(params.tiltangle_x, params.tiltangle_y) + 0.001
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// size of curved corners
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#pragma parameter cornersize "Corner Size" 0.02 0.0001 0.1 0.01
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#define cornersize params.cornersize
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// border smoothness parameter
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// decrease if borders are too aliased
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#pragma parameter cornersmooth "Corner Smoothness" 800.0 0.8 2000.0 50.0
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#define cornersmooth params.cornersmooth
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layout(std140, set = 0, binding = 0) uniform UBO
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{
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mat4 MVP;
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} global;
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#pragma stage vertex
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layout(location = 0) in vec4 Position;
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layout(location = 1) in vec2 TexCoord;
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layout(location = 0) out vec2 texCoord;
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layout(location = 1) out vec3 stretch;
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const vec2 aspect = vec2(1.0, 0.75);
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float d = distance;
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float R = radius;
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vec2 sinangle = sin(tiltangle);
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vec2 cosangle = cos(tiltangle);
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vec2 one;
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float mod_factor;
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vec2 ilfac;
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#define FIX(c) max(abs(c), 1e-5);
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float intersect(vec2 xy)
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{
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float A = dot(xy,xy)+d*d;
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float B = 2.0*(R*(dot(xy,sinangle)-d*cosangle.x*cosangle.y)-d*d);
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float C = d*d + 2.0*R*d*cosangle.x*cosangle.y;
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return (-B-sqrt(B*B-4.0*A*C))/(2.0*A);
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}
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vec2 bkwtrans(vec2 xy)
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{
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float c = intersect(xy);
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vec2 point = vec2(c)*xy;
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point -= vec2(-R)*sinangle;
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point /= vec2(R);
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vec2 tang = sinangle/cosangle;
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vec2 poc = point/cosangle;
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float A = dot(tang,tang)+1.0;
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float B = -2.0*dot(poc,tang);
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float C = dot(poc,poc)-1.0;
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float a = (-B+sqrt(B*B-4.0*A*C))/(2.0*A);
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vec2 uv = (point-a*sinangle)/cosangle;
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float r = R*acos(a);
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return uv*r/sin(r/R);
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}
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vec2 fwtrans(vec2 uv)
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{
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float r = FIX(sqrt(dot(uv,uv)));
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uv *= sin(r/R)/r;
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float x = 1.0-cos(r/R);
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float D = d/R + x*cosangle.x*cosangle.y+dot(uv,sinangle);
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return d*(uv*cosangle-x*sinangle)/D;
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}
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vec3 maxscale()
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{
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vec2 c = bkwtrans(-R * sinangle / (1.0 + R/d*cosangle.x*cosangle.y));
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vec2 a = vec2(0.5,0.5)*aspect;
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vec2 lo = vec2(fwtrans(vec2(-a.x,c.y)).x,
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fwtrans(vec2(c.x,-a.y)).y)/aspect;
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vec2 hi = vec2(fwtrans(vec2(+a.x,c.y)).x,
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fwtrans(vec2(c.x,+a.y)).y)/aspect;
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return vec3((hi+lo)*aspect*0.5,max(hi.x-lo.x,hi.y-lo.y));
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}
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void main()
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{
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gl_Position = global.MVP * Position;
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texCoord = TexCoord;
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stretch = maxscale();
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}
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#pragma stage fragment
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layout(location = 0) in vec2 texCoord;
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layout(location = 1) in vec3 stretch;
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layout(location = 0) out vec4 FragColor;
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layout(set = 0, binding = 2) uniform sampler2D Source;
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// Comment the next line to disable interpolation in linear gamma (and gain speed).
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//#define LINEAR_PROCESSING
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// Enable 3x oversampling of the beam profile
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#define OVERSAMPLE
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// Use the older, purely gaussian beam profile
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//#define USEGAUSSIAN
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// gamma of display monitor (typically 2.2 is correct)
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#define monitorgamma 2.2
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// aspect ratio
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const vec2 aspect = vec2(1.0, 0.75);
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// lengths are measured in units of (approximately) the width of the monitor
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// simulated distance from viewer to monitor
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float d = distance;
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float R = radius;
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vec2 sinangle = sin(tiltangle);
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vec2 cosangle = cos(tiltangle);
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#define one (params.SourceSize.zw)
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// Macros.
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#define FIX(c) max(abs(c), 1e-5);
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#define PI 3.141592653589
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#ifdef LINEAR_PROCESSING
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# define TEX2D(c) pow(texture(Source, (c)), vec4(CRTgamma))
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#else
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# define TEX2D(c) texture(Source, (c))
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#endif
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#define FIX(c) max(abs(c), 1e-5);
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float intersect(vec2 xy)
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{
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float A = dot(xy,xy)+d*d;
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float B = 2.0*(R*(dot(xy,sinangle)-d*cosangle.x*cosangle.y)-d*d);
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float C = d*d + 2.0*R*d*cosangle.x*cosangle.y;
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return (-B-sqrt(B*B-4.0*A*C))/(2.0*A);
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}
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vec2 bkwtrans(vec2 xy)
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{
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float c = intersect(xy);
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vec2 point = vec2(c)*xy;
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point -= vec2(-R)*sinangle;
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point /= vec2(R);
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vec2 tang = sinangle/cosangle;
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vec2 poc = point/cosangle;
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float A = dot(tang,tang)+1.0;
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float B = -2.0*dot(poc,tang);
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float C = dot(poc,poc)-1.0;
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float a = (-B+sqrt(B*B-4.0*A*C))/(2.0*A);
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vec2 uv = (point-a*sinangle)/cosangle;
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float r = FIX(R*acos(a));
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return uv*r/sin(r/R);
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}
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vec2 transform(vec2 coord)
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{
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coord = (coord-vec2(0.5))*aspect*stretch.z+stretch.xy;
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return (bkwtrans(coord)/overscan/aspect+vec2(0.5));
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}
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float corner(vec2 coord)
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{
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coord = (coord - vec2(0.5)) * overscan + vec2(0.5);
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coord = min(coord, vec2(1.0)-coord) * aspect;
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vec2 cdist = vec2(cornersize);
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coord = (cdist - min(coord,cdist));
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float dist = sqrt(dot(coord,coord));
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return clamp((cdist.x-dist)*cornersmooth,0.0, 1.0);
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}
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// Calculate the influence of a scanline on the current pixel.
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//
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// 'dist' is the distance in texture coordinates from the current
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// pixel to the scanline in question.
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// 'color' is the colour of the scanline at the horizontal location of
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// the current pixel.
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vec4 scanlineWeights(float dist, vec4 color)
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{
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// "wid" controls the width of the scanline beam, for each RGB channel
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// The "weights" lines basically specify the formula that gives
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// you the profile of the beam, i.e. the intensity as
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// a function of distance from the vertical center of the
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// scanline. In this case, it is gaussian if width=2, and
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// becomes nongaussian for larger widths. Ideally this should
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// be normalized so that the integral across the beam is
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// independent of its width. That is, for a narrower beam
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// "weights" should have a higher peak at the center of the
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// scanline than for a wider beam.
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#ifdef USEGAUSSIAN
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vec4 wid = 0.3 + 0.1 * pow(color, vec4(3.0));
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vec4 weights = vec4(dist / wid);
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return 0.4 * exp(-weights * weights) / wid;
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#else
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vec4 wid = 2.0 + 2.0 * pow(color, vec4(4.0));
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vec4 weights = vec4(dist / 0.3);
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return 1.4 * exp(-pow(weights * inversesqrt(0.5 * wid), wid)) / (0.6 + 0.2 * wid);
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#endif
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}
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void main()
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{
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// Here's a helpful diagram to keep in mind while trying to
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// understand the code:
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//
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// | | | | |
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// -------------------------------
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// | | | | |
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// | 01 | 11 | 21 | 31 | <-- current scanline
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// | | @ | | |
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// -------------------------------
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// | | | | |
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// | 02 | 12 | 22 | 32 | <-- next scanline
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// | | | | |
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// -------------------------------
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// | | | | |
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//
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// Each character-cell represents a pixel on the output
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// surface, "@" represents the current pixel (always somewhere
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// in the bottom half of the current scan-line, or the top-half
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// of the next scanline). The grid of lines represents the
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// edges of the texels of the underlying texture.
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// Texture coordinates of the texel containing the active pixel.
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vec2 xy = CURVATURE ? transform(texCoord) : texCoord;
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float cval = corner(xy);
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// Of all the pixels that are mapped onto the texel we are
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// currently rendering, which pixel are we currently rendering?
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vec2 ratio_scale = xy * params.SourceSize.xy - vec2(0.5);
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#ifdef OVERSAMPLE
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float filter_ = fwidth(ratio_scale.y);
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#endif
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vec2 uv_ratio = fract(ratio_scale);
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// Snap to the center of the underlying texel.
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xy = (floor(ratio_scale) + vec2(0.5)) / params.SourceSize.xy;
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// Calculate Lanczos scaling coefficients describing the effect
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// of various neighbour texels in a scanline on the current
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// pixel.
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vec4 coeffs = PI * vec4(1.0 + uv_ratio.x, uv_ratio.x, 1.0 - uv_ratio.x, 2.0 - uv_ratio.x);
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// Prevent division by zero.
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coeffs = FIX(coeffs);
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// Lanczos2 kernel.
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coeffs = 2.0 * sin(coeffs) * sin(coeffs / 2.0) / (coeffs * coeffs);
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// Normalize.
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coeffs /= dot(coeffs, vec4(1.0));
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// Calculate the effective colour of the current and next
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// scanlines at the horizontal location of the current pixel,
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// using the Lanczos coefficients above.
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vec4 col = clamp(mat4(
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TEX2D(xy + vec2(-one.x, 0.0)),
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TEX2D(xy),
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TEX2D(xy + vec2(one.x, 0.0)),
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TEX2D(xy + vec2(2.0 * one.x, 0.0))) * coeffs,
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0.0, 1.0);
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vec4 col2 = clamp(mat4(
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TEX2D(xy + vec2(-one.x, one.y)),
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TEX2D(xy + vec2(0.0, one.y)),
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TEX2D(xy + one),
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TEX2D(xy + vec2(2.0 * one.x, one.y))) * coeffs,
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0.0, 1.0);
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#ifndef LINEAR_PROCESSING
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col = pow(col , vec4(CRTgamma));
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col2 = pow(col2, vec4(CRTgamma));
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#endif
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// Calculate the influence of the current and next scanlines on
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// the current pixel.
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vec4 weights = scanlineWeights(uv_ratio.y, col);
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vec4 weights2 = scanlineWeights(1.0 - uv_ratio.y, col2);
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#ifdef OVERSAMPLE
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uv_ratio.y =uv_ratio.y+1.0/3.0*filter_;
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weights = (weights+scanlineWeights(uv_ratio.y, col))/3.0;
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weights2=(weights2+scanlineWeights(abs(1.0-uv_ratio.y), col2))/3.0;
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uv_ratio.y =uv_ratio.y-2.0/3.0*filter_;
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weights=weights+scanlineWeights(abs(uv_ratio.y), col)/3.0;
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weights2=weights2+scanlineWeights(abs(1.0-uv_ratio.y), col2)/3.0;
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#endif
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vec3 mul_res = (col * weights + col2 * weights2).rgb * vec3(cval);
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// dot-mask emulation:
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// Output pixels are alternately tinted green and magenta.
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vec3 dotMaskWeights = mix(
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vec3(1.0, 0.7, 1.0),
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vec3(0.7, 1.0, 0.7),
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floor(mod(texCoord.x*params.OutputSize.x, 2.0))
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);
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mul_res *= dotMaskWeights;
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// Convert the image gamma for display on our output device.
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mul_res = pow(mul_res, vec3(1.0 / monitorgamma));
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// Color the texel.
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FragColor = vec4(mul_res, 1.0);
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}
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