slang-shaders/crt/shaders/crt-royale/src/derived-settings-and-constants.h

#ifndef DERIVED_SETTINGS_AND_CONSTANTS_H
#define DERIVED_SETTINGS_AND_CONSTANTS_H

/////////////////////////////  GPL LICENSE NOTICE  /////////////////////////////

//  crt-royale: A full-featured CRT shader, with cheese.
//  Copyright (C) 2014 TroggleMonkey <trogglemonkey@gmx.com>
//
//  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 any later version.
//
//  This program is distributed in the hope that it will be useful, but WITHOUT
//  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
//  more details.
//
//  You should have received a copy of the GNU General Public License along with
//  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
//  Place, Suite 330, Boston, MA 02111-1307 USA


/////////////////////////////////  DESCRIPTION  ////////////////////////////////

//  These macros and constants can be used across the whole codebase.
//  Unlike the values in user-settings.cgh, end users shouldn't modify these.


//////////////////////////////////  INCLUDES  //////////////////////////////////

#include "../user-settings.h"
#include "user-preset-constants.h"


///////////////////////////////  FIXED SETTINGS  ///////////////////////////////

//  Avoid dividing by zero; using a macro overloads for float, vec2, etc.:
#define FIX_ZERO(c) (max(abs(c), 0.0000152587890625))   //  2^-16

//  Ensure the first pass decodes CRT gamma and the last encodes LCD gamma.
#ifndef SIMULATE_CRT_ON_LCD
    #define SIMULATE_CRT_ON_LCD
#endif

//  Manually tiling a manually resized texture creates texture coord derivative
//  discontinuities and confuses anisotropic filtering, causing discolored tile
//  seams in the phosphor mask.  Workarounds:
//  a.) Using tex2Dlod disables anisotropic filtering for tiled masks.  It's
//      downgraded to tex2Dbias without DRIVERS_ALLOW_TEX2DLOD #defined and
//      disabled without DRIVERS_ALLOW_TEX2DBIAS #defined either.
//  b.) "Tile flat twice" requires drawing two full tiles without border padding
//      to the resized mask FBO, and it's incompatible with same-pass curvature.
//      (Same-pass curvature isn't used but could be in the future...maybe.)
//  c.) "Fix discontinuities" requires derivatives and drawing one tile with
//      border padding to the resized mask FBO, but it works with same-pass
//      curvature.  It's disabled without DRIVERS_ALLOW_DERIVATIVES #defined.
//  Precedence: a, then, b, then c (if multiple strategies are #defined).
    #define ANISOTROPIC_TILING_COMPAT_TEX2DLOD              //  129.7 FPS, 4x, flat; 101.8 at fullscreen
    #define ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE       //  128.1 FPS, 4x, flat; 101.5 at fullscreen
    #define ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES   //  124.4 FPS, 4x, flat; 97.4 at fullscreen
//  Also, manually resampling the phosphor mask is slightly blurrier with
//  anisotropic filtering.  (Resampling with mipmapping is even worse: It
//  creates artifacts, but only with the fully bloomed shader.)  The difference
//  is subtle with small triads, but you can fix it for a small cost.
    //#define ANISOTROPIC_RESAMPLING_COMPAT_TEX2DLOD


//////////////////////////////  DERIVED SETTINGS  //////////////////////////////

//  Intel HD 4000 GPU's can't handle manual mask resizing (for now), setting the
//  geometry mode at runtime, or a 4x4 true Gaussian resize.  Disable
//  incompatible settings ASAP.  (INTEGRATED_GRAPHICS_COMPATIBILITY_MODE may be
//  #defined by either user-settings.h or a wrapper .cg that #includes the
//  current .cg pass.)
#ifdef INTEGRATED_GRAPHICS_COMPATIBILITY_MODE
    #ifdef PHOSPHOR_MASK_MANUALLY_RESIZE
        #undef PHOSPHOR_MASK_MANUALLY_RESIZE
    #endif
    #ifdef RUNTIME_GEOMETRY_MODE
        #undef RUNTIME_GEOMETRY_MODE
    #endif
    //  Mode 2 (4x4 Gaussian resize) won't work, and mode 1 (3x3 blur) is
    //  inferior in most cases, so replace 2.0 with 0.0:
     const float bloom_approx_filter =
        bloom_approx_filter_static > 1.5 ? 0.0 : bloom_approx_filter_static;
#else
     const float bloom_approx_filter = bloom_approx_filter_static;
#endif

//  Disable slow runtime paths if static parameters are used.  Most of these
//  won't be a problem anyway once the params are disabled, but some will.
#ifndef RUNTIME_SHADER_PARAMS_ENABLE
    #ifdef RUNTIME_PHOSPHOR_BLOOM_SIGMA
        #undef RUNTIME_PHOSPHOR_BLOOM_SIGMA
    #endif
    #ifdef RUNTIME_ANTIALIAS_WEIGHTS
        #undef RUNTIME_ANTIALIAS_WEIGHTS
    #endif
    #ifdef RUNTIME_ANTIALIAS_SUBPIXEL_OFFSETS
        #undef RUNTIME_ANTIALIAS_SUBPIXEL_OFFSETS
    #endif
    #ifdef RUNTIME_SCANLINES_HORIZ_FILTER_COLORSPACE
        #undef RUNTIME_SCANLINES_HORIZ_FILTER_COLORSPACE
    #endif
    #ifdef RUNTIME_GEOMETRY_TILT
        #undef RUNTIME_GEOMETRY_TILT
    #endif
    #ifdef RUNTIME_GEOMETRY_MODE
        #undef RUNTIME_GEOMETRY_MODE
    #endif
    #ifdef FORCE_RUNTIME_PHOSPHOR_MASK_MODE_TYPE_SELECT
        #undef FORCE_RUNTIME_PHOSPHOR_MASK_MODE_TYPE_SELECT
    #endif
#endif

//  Make tex2Dbias a backup for tex2Dlod for wider compatibility.
#ifdef ANISOTROPIC_TILING_COMPAT_TEX2DLOD
    #define ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
#endif
#ifdef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DLOD
    #define ANISOTROPIC_RESAMPLING_COMPAT_TEX2DBIAS
#endif
//  Rule out unavailable anisotropic compatibility strategies:
#ifndef DRIVERS_ALLOW_DERIVATIVES
    #ifdef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
        #undef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
    #endif
#endif
#ifndef DRIVERS_ALLOW_TEX2DLOD
    #ifdef ANISOTROPIC_TILING_COMPAT_TEX2DLOD
        #undef ANISOTROPIC_TILING_COMPAT_TEX2DLOD
    #endif
    #ifdef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DLOD
        #undef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DLOD
    #endif
    #ifdef ANTIALIAS_DISABLE_ANISOTROPIC
        #undef ANTIALIAS_DISABLE_ANISOTROPIC
    #endif
#endif
#ifndef DRIVERS_ALLOW_TEX2DBIAS
    #ifdef ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
        #undef ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
    #endif
    #ifdef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DBIAS
        #undef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DBIAS
    #endif
#endif
//  Prioritize anisotropic tiling compatibility strategies by performance and
//  disable unused strategies.  This concentrates all the nesting in one place.
#ifdef ANISOTROPIC_TILING_COMPAT_TEX2DLOD
    #ifdef ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
        #undef ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
    #endif
    #ifdef ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE
        #undef ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE
    #endif
    #ifdef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
        #undef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
    #endif
#else
    #ifdef ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
        #ifdef ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE
            #undef ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE
        #endif
        #ifdef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
            #undef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
        #endif
    #else
        //  ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE is only compatible with
        //  flat texture coords in the same pass, but that's all we use.
        #ifdef ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE
            #ifdef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
                #undef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
            #endif
        #endif
    #endif
#endif
//  The tex2Dlod and tex2Dbias strategies share a lot in common, and we can
//  reduce some #ifdef nesting in the next section by essentially OR'ing them:
#ifdef ANISOTROPIC_TILING_COMPAT_TEX2DLOD
    #define ANISOTROPIC_TILING_COMPAT_TEX2DLOD_FAMILY
#endif
#ifdef ANISOTROPIC_TILING_COMPAT_TEX2DBIAS
    #define ANISOTROPIC_TILING_COMPAT_TEX2DLOD_FAMILY
#endif
//  Prioritize anisotropic resampling compatibility strategies the same way:
#ifdef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DLOD
    #ifdef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DBIAS
        #undef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DBIAS
    #endif
#endif


///////////////////////  DERIVED PHOSPHOR MASK CONSTANTS  //////////////////////

//  If we can use the large mipmapped LUT without mipmapping artifacts, we
//  should: It gives us more options for using fewer samples.
#ifdef DRIVERS_ALLOW_TEX2DLOD
    #ifdef ANISOTROPIC_RESAMPLING_COMPAT_TEX2DLOD
        //  TODO: Take advantage of this!
        #define PHOSPHOR_MASK_RESIZE_MIPMAPPED_LUT
         const vec2 mask_resize_src_lut_size = mask_texture_large_size;
    #else
         const vec2 mask_resize_src_lut_size = mask_texture_small_size;
    #endif
#else
     const vec2 mask_resize_src_lut_size = mask_texture_small_size;
#endif


//  tex2D's sampler2D parameter MUST be a uniform global, a uniform input to
//  main_fragment, or a static alias of one of the above.  This makes it hard
//  to select the phosphor mask at runtime: We can't even assign to a uniform
//  global in the vertex shader or select a sampler2D in the vertex shader and
//  pass it to the fragment shader (even with explicit TEXUNIT# bindings),
//  because it just gives us the input texture or a black screen.  However, we
//  can get around these limitations by calling tex2D three times with different
//  uniform samplers (or resizing the phosphor mask three times altogether).
//  With dynamic branches, we can process only one of these branches on top of
//  quickly discarding fragments we don't need (cgc seems able to overcome
//  limigations around dependent texture fetches inside of branches).  Without
//  dynamic branches, we have to process every branch for every fragment...which
//  is slower.  Runtime sampling mode selection is slower without dynamic
//  branches as well.  Let the user's static #defines decide if it's worth it.
#ifdef DRIVERS_ALLOW_DYNAMIC_BRANCHES
    #define RUNTIME_PHOSPHOR_MASK_MODE_TYPE_SELECT
#else
    #ifdef FORCE_RUNTIME_PHOSPHOR_MASK_MODE_TYPE_SELECT
        #define RUNTIME_PHOSPHOR_MASK_MODE_TYPE_SELECT
    #endif
#endif

//  We need to render some minimum number of tiles in the resize passes.
//  We need at least 1.0 just to repeat a single tile, and we need extra
//  padding beyond that for anisotropic filtering, discontinuitity fixing,
//  antialiasing, same-pass curvature (not currently used), etc.  First
//  determine how many border texels and tiles we need, based on how the result
//  will be sampled:
#ifdef GEOMETRY_EARLY
         const float max_subpixel_offset = aa_subpixel_r_offset_static.x;
        //  Most antialiasing filters have a base radius of 4.0 pixels:
         const float max_aa_base_pixel_border = 4.0 +
            max_subpixel_offset;
#else
     const float max_aa_base_pixel_border = 0.0;
#endif
//  Anisotropic filtering adds about 0.5 to the pixel border:
#ifndef ANISOTROPIC_TILING_COMPAT_TEX2DLOD_FAMILY
     const float max_aniso_pixel_border = max_aa_base_pixel_border + 0.5;
#else
     const float max_aniso_pixel_border = max_aa_base_pixel_border;
#endif
//  Fixing discontinuities adds 1.0 more to the pixel border:
#ifdef ANISOTROPIC_TILING_COMPAT_FIX_DISCONTINUITIES
     const float max_tiled_pixel_border = max_aniso_pixel_border + 1.0;
#else
     const float max_tiled_pixel_border = max_aniso_pixel_border;
#endif
//  Convert the pixel border to an integer texel border.  Assume same-pass
//  curvature about triples the texel frequency:
#ifdef GEOMETRY_EARLY
     const float max_mask_texel_border =
        ceil(max_tiled_pixel_border * 3.0);
#else
     const float max_mask_texel_border = ceil(max_tiled_pixel_border);
#endif
//  Convert the texel border to a tile border using worst-case assumptions:
 const float max_mask_tile_border = max_mask_texel_border/
    (mask_min_allowed_triad_size * mask_triads_per_tile);

//  Finally, set the number of resized tiles to render to MASK_RESIZE, and set
//  the starting texel (inside borders) for sampling it.
#ifndef GEOMETRY_EARLY
    #ifdef ANISOTROPIC_TILING_COMPAT_TILE_FLAT_TWICE
        //  Special case: Render two tiles without borders.  Anisotropic
        //  filtering doesn't seem to be a problem here.
         const float mask_resize_num_tiles = 1.0 + 1.0;
         const float mask_start_texels = 0.0;
    #else
         const float mask_resize_num_tiles = 1.0 +
            2.0 * max_mask_tile_border;
         const float mask_start_texels = max_mask_texel_border;
    #endif
#else
     const float mask_resize_num_tiles = 1.0 + 2.0*max_mask_tile_border;
     const float mask_start_texels = max_mask_texel_border;
#endif

//  We have to fit mask_resize_num_tiles into an FBO with a viewport scale of
//  mask_resize_viewport_scale.  This limits the maximum final triad size.
//  Estimate the minimum number of triads we can split the screen into in each
//  dimension (we'll be as correct as mask_resize_viewport_scale is):
 const float mask_resize_num_triads =
    mask_resize_num_tiles * mask_triads_per_tile;
 const vec2 min_allowed_viewport_triads =
    vec2(mask_resize_num_triads) / mask_resize_viewport_scale;


////////////////////////  COMMON MATHEMATICAL CONSTANTS  ///////////////////////

 const float pi = 3.141592653589;
//  We often want to find the location of the previous texel, e.g.:
//      const vec2 curr_texel = uv * texture_size;
//      const vec2 prev_texel = floor(curr_texel - vec2(0.5)) + vec2(0.5);
//      const vec2 prev_texel_uv = prev_texel / texture_size;
//  However, many GPU drivers round incorrectly around exact texel locations.
//  We need to subtract a little less than 0.5 before flooring, and some GPU's
//  require this value to be farther from 0.5 than others; define it here.
//      const vec2 prev_texel =
//          floor(curr_texel - vec2(under_half)) + vec2(0.5);
 const float under_half = 0.4995;


#endif  //  DERIVED_SETTINGS_AND_CONSTANTS_H