snes_ntsc.h

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/* SNES NTSC video filter */

/* snes_ntsc 0.2.2 */
#ifndef SNES_NTSC_H
#define SNES_NTSC_H

#include "snes_ntsc_config.h"

#ifdef __cplusplus
    extern "C" {
#endif

/* Image parameters, ranging from -1.0 to 1.0. Actual internal values shown
in parenthesis and should remain fairly stable in future versions. */
typedef struct snes_ntsc_setup_t
{
    /* Basic parameters */
    double hue;        /* -1 = -180 degrees     +1 = +180 degrees */
    double saturation; /* -1 = grayscale (0.0)  +1 = oversaturated colors (2.0) */
    double contrast;   /* -1 = dark (0.5)       +1 = light (1.5) */
    double brightness; /* -1 = dark (0.5)       +1 = light (1.5) */
    double sharpness;  /* edge contrast enhancement/blurring */

    /* Advanced parameters */
    double gamma;      /* -1 = dark (1.5)       +1 = light (0.5) */
    double resolution; /* image resolution */
    double artifacts;  /* artifacts caused by color changes */
    double fringing;   /* color artifacts caused by brightness changes */
    double bleed;      /* color bleed (color resolution reduction) */
    int merge_fields;  /* if 1, merges even and odd fields together to reduce flicker */
    float const* decoder_matrix; /* optional RGB decoder matrix, 6 elements */

    unsigned long const* bsnes_colortbl; /* undocumented; set to 0 */
} snes_ntsc_setup_t;

/* Video format presets */
extern snes_ntsc_setup_t const snes_ntsc_composite; /* color bleeding + artifacts */
extern snes_ntsc_setup_t const snes_ntsc_svideo;    /* color bleeding only */
extern snes_ntsc_setup_t const snes_ntsc_rgb;       /* crisp image */
extern snes_ntsc_setup_t const snes_ntsc_monochrome;/* desaturated + artifacts */

/* Initializes and adjusts parameters. Can be called multiple times on the same
snes_ntsc_t object. Can pass NULL for either parameter. */
typedef struct snes_ntsc_t snes_ntsc_t;
void snes_ntsc_init( snes_ntsc_t* ntsc, snes_ntsc_setup_t const* setup );

/* Filters one or more rows of pixels. Input pixel format is set by SNES_NTSC_IN_FORMAT
and output RGB depth is set by SNES_NTSC_OUT_DEPTH. Both default to 16-bit RGB.
In_row_width is the number of pixels to get to the next input row. Out_pitch
is the number of *bytes* to get to the next output row. */
void snes_ntsc_blit( snes_ntsc_t const* ntsc, SNES_NTSC_IN_T const* input,
        long in_row_width, int burst_phase, int in_width, int in_height,
        void* rgb_out, long out_pitch, int first, int last);

void snes_ntsc_blit_hires( snes_ntsc_t const* ntsc, SNES_NTSC_IN_T const* input,
        long in_row_width, int burst_phase, int in_width, int in_height,
        void* rgb_out, long out_pitch, int first, int last);

/* Number of output pixels written by low-res blitter for given input width. Width
might be rounded down slightly; use SNES_NTSC_IN_WIDTH() on result to find rounded
value. Guaranteed not to round 256 down at all. */
#define SNES_NTSC_OUT_WIDTH( in_width ) \
    ((((in_width) - 1) / snes_ntsc_in_chunk + 1) * snes_ntsc_out_chunk)

/* Number of low-res input pixels that will fit within given output width. Might be
rounded down slightly; use SNES_NTSC_OUT_WIDTH() on result to find rounded
value. */
#define SNES_NTSC_IN_WIDTH( out_width ) \
    (((out_width) / snes_ntsc_out_chunk - 1) * snes_ntsc_in_chunk + 1)


/* Interface for user-defined custom blitters */

enum { snes_ntsc_in_chunk    = 3  }; /* number of input pixels read per chunk */
enum { snes_ntsc_out_chunk   = 7  }; /* number of output pixels generated per chunk */
enum { snes_ntsc_black       = 0  }; /* palette index for black */
enum { snes_ntsc_burst_count = 3  }; /* burst phase cycles through 0, 1, and 2 */

/* Begins outputting row and starts three pixels. First pixel will be cut off a bit.
Use snes_ntsc_black for unused pixels. Declares variables, so must be before first
statement in a block (unless you're using C++). */
#define SNES_NTSC_BEGIN_ROW( ntsc, burst, pixel0, pixel1, pixel2 ) \
    char const* ktable = \
        (char const*) (ntsc)->table + burst * (snes_ntsc_burst_size * sizeof (snes_ntsc_rgb_t));\
    SNES_NTSC_BEGIN_ROW_6_( pixel0, pixel1, pixel2, SNES_NTSC_IN_FORMAT, ktable )

/* Begins input pixel */
#define SNES_NTSC_COLOR_IN( index, color ) \
    SNES_NTSC_COLOR_IN_( index, color, SNES_NTSC_IN_FORMAT, ktable )

/* Generates output pixel. Bits can be 24, 16, 15, 14, 32 (treated as 24), or 0:
24:          RRRRRRRR GGGGGGGG BBBBBBBB (8-8-8 RGB)
16:                   RRRRRGGG GGGBBBBB (5-6-5 RGB)
15:                    RRRRRGG GGGBBBBB (5-5-5 RGB)
14:                    BBBBBGG GGGRRRRR (5-5-5 BGR, native SNES format)
 0: xxxRRRRR RRRxxGGG GGGGGxxB BBBBBBBx (native internal format; x = junk bits) */
#define SNES_NTSC_RGB_OUT( index, rgb_out, bits ) \
    SNES_NTSC_RGB_OUT_14_( index, rgb_out, bits, 1 )

/* Hires equivalents */
#define SNES_NTSC_HIRES_ROW( ntsc, burst, pixel1, pixel2, pixel3, pixel4, pixel5 ) \
    char const* ktable = \
        (char const*) (ntsc)->table + burst * (snes_ntsc_burst_size * sizeof (snes_ntsc_rgb_t));\
    unsigned const snes_ntsc_pixel1_ = (pixel1);\
    snes_ntsc_rgb_t const* kernel1  = SNES_NTSC_IN_FORMAT( ktable, snes_ntsc_pixel1_ );\
    unsigned const snes_ntsc_pixel2_ = (pixel2);\
    snes_ntsc_rgb_t const* kernel2  = SNES_NTSC_IN_FORMAT( ktable, snes_ntsc_pixel2_ );\
    unsigned const snes_ntsc_pixel3_ = (pixel3);\
    snes_ntsc_rgb_t const* kernel3  = SNES_NTSC_IN_FORMAT( ktable, snes_ntsc_pixel3_ );\
    unsigned const snes_ntsc_pixel4_ = (pixel4);\
    snes_ntsc_rgb_t const* kernel4  = SNES_NTSC_IN_FORMAT( ktable, snes_ntsc_pixel4_ );\
    unsigned const snes_ntsc_pixel5_ = (pixel5);\
    snes_ntsc_rgb_t const* kernel5  = SNES_NTSC_IN_FORMAT( ktable, snes_ntsc_pixel5_ );\
    snes_ntsc_rgb_t const* kernel0 = kernel1;\
    snes_ntsc_rgb_t const* kernelx0;\
    snes_ntsc_rgb_t const* kernelx1 = kernel1;\
    snes_ntsc_rgb_t const* kernelx2 = kernel1;\
    snes_ntsc_rgb_t const* kernelx3 = kernel1;\
    snes_ntsc_rgb_t const* kernelx4 = kernel1;\
    snes_ntsc_rgb_t const* kernelx5 = kernel1

#define SNES_NTSC_HIRES_OUT( x, rgb_out, bits ) {\
    snes_ntsc_rgb_t raw_ =\
        kernel0  [ x       ] + kernel2  [(x+5)%7+14] + kernel4  [(x+3)%7+28] +\
        kernelx0 [(x+7)%7+7] + kernelx2 [(x+5)%7+21] + kernelx4 [(x+3)%7+35] +\
        kernel1  [(x+6)%7  ] + kernel3  [(x+4)%7+14] + kernel5  [(x+2)%7+28] +\
        kernelx1 [(x+6)%7+7] + kernelx3 [(x+4)%7+21] + kernelx5 [(x+2)%7+35];\
    SNES_NTSC_CLAMP_( raw_, 0 );\
    SNES_NTSC_RGB_OUT_( rgb_out, (bits), 0 );\
}


/* private */
enum { snes_ntsc_entry_size = 128 };
enum { snes_ntsc_palette_size = 0x2000 };
typedef unsigned long snes_ntsc_rgb_t;
struct snes_ntsc_t {
    snes_ntsc_rgb_t table [snes_ntsc_palette_size] [snes_ntsc_entry_size];
};
enum { snes_ntsc_burst_size = snes_ntsc_entry_size / snes_ntsc_burst_count };

#define SNES_NTSC_RGB16( ktable, n ) \
    (snes_ntsc_rgb_t const*) (ktable + ((n & 0x001E) | (n >> 1 & 0x03E0) | (n >> 2 & 0x3C00)) * \
            (snes_ntsc_entry_size / 2 * sizeof (snes_ntsc_rgb_t)))

#define SNES_NTSC_BGR15( ktable, n ) \
    (snes_ntsc_rgb_t const*) (ktable + ((n << 9 & 0x3C00) | (n & 0x03E0) | (n >> 10 & 0x001E)) * \
            (snes_ntsc_entry_size / 2 * sizeof (snes_ntsc_rgb_t)))

/* common 3->7 ntsc macros */
#define SNES_NTSC_BEGIN_ROW_6_( pixel0, pixel1, pixel2, ENTRY, table ) \
    unsigned const snes_ntsc_pixel0_ = (pixel0);\
    snes_ntsc_rgb_t const* kernel0  = ENTRY( table, snes_ntsc_pixel0_ );\
    unsigned const snes_ntsc_pixel1_ = (pixel1);\
    snes_ntsc_rgb_t const* kernel1  = ENTRY( table, snes_ntsc_pixel1_ );\
    unsigned const snes_ntsc_pixel2_ = (pixel2);\
    snes_ntsc_rgb_t const* kernel2  = ENTRY( table, snes_ntsc_pixel2_ );\
    snes_ntsc_rgb_t const* kernelx0;\
    snes_ntsc_rgb_t const* kernelx1 = kernel0;\
    snes_ntsc_rgb_t const* kernelx2 = kernel0

#define SNES_NTSC_RGB_OUT_14_( x, rgb_out, bits, shift ) {\
    snes_ntsc_rgb_t raw_ =\
        kernel0  [x       ] + kernel1  [(x+12)%7+14] + kernel2  [(x+10)%7+28] +\
        kernelx0 [(x+7)%14] + kernelx1 [(x+ 5)%7+21] + kernelx2 [(x+ 3)%7+35];\
    SNES_NTSC_CLAMP_( raw_, shift );\
    SNES_NTSC_RGB_OUT_( rgb_out, bits, shift );\
}

/* common ntsc macros */
#define snes_ntsc_rgb_builder    ((1L << 21) | (1 << 11) | (1 << 1))
#define snes_ntsc_clamp_mask     (snes_ntsc_rgb_builder * 3 / 2)
#define snes_ntsc_clamp_add      (snes_ntsc_rgb_builder * 0x101)
#define SNES_NTSC_CLAMP_( io, shift ) {\
    snes_ntsc_rgb_t sub = (io) >> (9-(shift)) & snes_ntsc_clamp_mask;\
    snes_ntsc_rgb_t clamp = snes_ntsc_clamp_add - sub;\
    io |= clamp;\
    clamp -= sub;\
    io &= clamp;\
}

#define SNES_NTSC_COLOR_IN_( index, color, ENTRY, table ) {\
    unsigned color_;\
    kernelx##index = kernel##index;\
    kernel##index = (color_ = (color), ENTRY( table, color_ ));\
}

/* x is always zero except in snes_ntsc library */
/* original routine */
#define SNES_NTSC_RGB_OUT_( rgb_out, bits, x ) {\
    if ( bits == 16 )\
        rgb_out = (raw_>>(13-x)& 0xF800)|(raw_>>(8-x)&0x07E0)|(raw_>>(4-x)&0x001F);\
    if ( bits == 24 || bits == 32 )\
        rgb_out = (raw_>>(5-x)&0xFF0000)|(raw_>>(3-x)&0xFF00)|(raw_>>(1-x)&0xFF);\
    if ( bits == 15 )\
        rgb_out = (raw_>>(14-x)& 0x7C00)|(raw_>>(9-x)&0x03E0)|(raw_>>(4-x)&0x001F);\
    if ( bits == 14 )\
        rgb_out = (raw_>>(24-x)& 0x001F)|(raw_>>(9-x)&0x03E0)|(raw_<<(6+x)&0x7C00);\
    if ( bits == 0 )\
        rgb_out = raw_ << x;\
}

#ifdef __cplusplus
    }
#endif

#endif