CRT-Geom-Flat.cg

/* COMPATIBILITY
   - HLSL compilers
   - Cg   compilers
*/

// This is a good place for any #defines you might have
#define FIX(c) max(abs(c), 1e-5);

// Comment the next line to disable interpolation in linear gamma (and gain speed).
#define LINEAR_PROCESSING

// Enable 3x oversampling of the beam profile
#define OVERSAMPLE

// Use the older, purely gaussian beam profile
//#define USEGAUSSIAN

// Use interlacing detection; may interfere with other shaders if combined
#define INTERLACED

#define SHARPER

// Macros.
#define FIX(c) max(abs(c), 1e-5);
#define PI 3.141592653589

#ifdef LINEAR_PROCESSING
#       define TEX2D(c) pow(tex2D(IN.texture, (c)), float4(CRTgamma))
#else
#       define TEX2D(c) tex2D(IN.texture, (c))
#endif

  // gamma of simulated CRT
#define CRTgamma 2.4

  // gamma of display monitor (typically 2.2 is correct)
#define monitorgamma 2.2

struct input      // These are things that can attach to 'IN' to achieve similar function to ruby* stuff in existing GLSL shaders. NOTE: the ruby* prefix is deprecated but still works in GLSL for legacy compatibility purposes.
{
  float2 video_size;
  float2 texCoord_size;
  float2 output_size;
  float frame_count;
  float frame_direction;
  float frame_rotation;
  float texture_size;
  sampler2D texture : TEXUNIT0;
};

struct tex_coords
{
   float2 texCoord  : TEXCOORD0;
   float2 one       : TEXCOORD2;
};

// VERTEX SHADER //

void main_vertex
(
   float4 position : POSITION,
   out float4 oPosition : POSITION,
   uniform float4x4 modelViewProj,

   float4 color : COLOR,
   out float4 oColor : COLOR,

   float2 tex : TEXCOORD,

   uniform input IN,
   out tex_coords coords
 )
{
   oPosition = mul(modelViewProj, position);
   oColor = color;

#ifdef SHARPER
  float2 TextureSize = float2(2.0*IN.texture_size.x, IN.texture_size.y);
#else
  float2 TextureSize = IN.texture_size;
#endif

   coords.texCoord = tex + float2(0.0, 0.0);
   coords.one = 1.0 / TextureSize;
}



// 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)
{
  // "wid" controls the width of the scanline beam, for each RGB channel
  // 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.
#ifdef USEGAUSSIAN
  float4 wid = 0.3 + 0.1 * pow(color, float4(3.0));
  float4 weights = float4(distance / wid);
  return 0.4 * exp(-weights * weights) / wid;
#else
  float4 wid = 2.0 + 2.0 * pow(color, float4(4.0));
  float4 weights = float4(distance / 0.4);
  return 1.4 * exp(-pow(weights * inversesqrt(0.5 * wid), wid)) / (0.6 + 0.2 * wid);
#endif
}

// FRAGMENT SHADER //

float4 main_fragment(in tex_coords co, uniform input IN, uniform sampler2D s_p : TEXUNIT0) : COLOR
{
// Paste your fragment code--the part that is inside the GLSL shader's "void main(){ ... }"--here:
// 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.
  float2 xy = co.texCoord;

  float2 ilfac = float2(1.0,floor(IN.video_size.y/200.0));

#ifdef SHARPER
  float2 TextureSize = float2(2.0*IN.texture_size.x, IN.texture_size.y);
#else
  float2 TextureSize = IN.texture_size;
#endif

 // The size of one texel, in texture-coordinates.
  float2 one = ilfac / TextureSize;

  float2 ilvec = float2(0.0,ilfac.y > 1.5 ? mod(float(IN.frame_count),2.0) : 0.0);

  // Of all the pixels that are mapped onto the texel we are
  // currently rendering, which pixel are we currently rendering?
#ifdef INTERLACED
  float2 ratio_scale = (xy * TextureSize - float2(0.5) + ilvec)/ilfac;
#else
  float2 ratio_scale = xy * TextureSize - float2(0.5);
#endif

#ifdef OVERSAMPLE
  float filter = (IN.video_size / (IN.output_size * TextureSize)) *(ratio_scale.y);
#endif
  float2 uv_ratio = fract(ratio_scale);

  // Snap to the center of the underlying texel.
#ifdef INTERLACED
  xy = (floor(ratio_scale)*ilfac + float2(0.5) - ilvec) / TextureSize;
#else
  xy = (floor(ratio_scale) + float2(0.5)) / TextureSize;
#endif

  // 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, float4(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(-co.one.x, 0.0)),
                    TEX2D(xy),
                    TEX2D(xy + float2(co.one.x, 0.0)),
                    TEX2D(xy + float2(2.0 * co.one.x, 0.0)))),
            0.0, 1.0);
    float4 col2 = clamp(mul(coeffs, float4x4(
                    TEX2D(xy + float2(-co.one.x, co.one.y)),
                    TEX2D(xy + float2(0.0, co.one.y)),
                    TEX2D(xy + co.one),
                    TEX2D(xy + float2(2.0 * co.one.x, co.one.y)))),
            0.0, 1.0);

#ifndef LINEAR_PROCESSING
  col  = pow(col , float4(CRTgamma));
  col2 = pow(col2, float4(CRTgamma));
#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);
#ifdef OVERSAMPLE
  uv_ratio.y =uv_ratio.y+1.0/3.0*filter;
  weights = (weights+scanlineWeights(uv_ratio.y, col))/3.0;
  weights2=(weights2+scanlineWeights(abs(1.0-uv_ratio.y), col2))/3.0;
  uv_ratio.y =uv_ratio.y-2.0/3.0*filter;
  weights=weights+scanlineWeights(abs(uv_ratio.y), col)/3.0;
  weights2=weights2+scanlineWeights(abs(1.0-uv_ratio.y), col2)/3.0;
#endif
  float3 mul_res  = (col * weights + col2 * weights2).rgb;

  // Convert the image gamma for display on our output device.
  mul_res = pow(mul_res, float3(1.0 / monitorgamma));

   return float4(mul_res, 1.0);
}