200 lines
8.2 KiB
C
200 lines
8.2 KiB
C
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/* NES NTSC video filter */
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/* nes_ntsc 0.2.0 */
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#ifndef NES_NTSC_H
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#define NES_NTSC_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Image parameters, ranging from -1.0 to 1.0. Actual internal values shown
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in parenthesis and should remain fairly stable in future versions. */
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typedef struct nes_ntsc_setup_t
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{
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/* Basic parameters */
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double hue; /* -1 = -180 degrees +1 = +180 degrees */
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double saturation; /* -1 = grayscale (0.0) +1 = oversaturated colors (2.0) */
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double contrast; /* -1 = dark (0.5) +1 = light (1.5) */
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double brightness; /* -1 = dark (0.5) +1 = light (1.5) */
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double sharpness; /* edge contrast enhancement/blurring */
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/* Advanced parameters */
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double gamma; /* -1 = dark (1.5) +1 = light (0.5) */
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double resolution; /* image resolution */
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double artifacts; /* artifacts caused by color changes */
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double fringing; /* color artifacts caused by brightness changes */
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double bleed; /* color bleed (color resolution reduction) */
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int merge_fields; /* if 1, merges even and odd fields together to reduce flicker */
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float const* decoder_matrix; /* optional RGB decoder matrix, 6 elements */
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unsigned char* palette_out; /* optional RGB palette out, 3 bytes per color */
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} nes_ntsc_setup_t;
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/* Video format presets */
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extern nes_ntsc_setup_t const nes_ntsc_composite; /* color bleeding + artifacts */
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extern nes_ntsc_setup_t const nes_ntsc_svideo; /* color bleeding only */
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extern nes_ntsc_setup_t const nes_ntsc_rgb; /* crisp image */
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extern nes_ntsc_setup_t const nes_ntsc_monochrome;/* desaturated + artifacts */
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enum { nes_ntsc_palette_size = 64 };
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enum { nes_ntsc_emph_palette_size = 64 * 8 };
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/* Initialize and adjust parameters. Can be called multiple times on the same
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nes_ntsc_t object. Can pass 0 for either parameter. */
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typedef struct nes_ntsc_t nes_ntsc_t;
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void nes_ntsc_init( nes_ntsc_t* ntsc, nes_ntsc_setup_t const* setup );
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/* Filter one or more rows of pixels. Input pixels are 6-bit palette indicies.
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In_row_width is the number of pixels to get to the next input row. Out_pitch
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is the number of *bytes* to get to the next output row. Output pixel format
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is set by NES_NTSC_OUT_DEPTH (defaults to 16-bit RGB). */
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void nes_ntsc_blit( nes_ntsc_t const* ntsc, unsigned char const* nes_in,
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long in_row_width, int burst_phase, int in_width, int in_height,
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void* rgb_out, long out_pitch );
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/* Equivalent functions with color emphasis support. Source pixels are
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9-bit values with the upper 3 bits specifying the emphasis bits from
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PPU register 0x2001. */
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typedef struct nes_ntsc_emph_t nes_ntsc_emph_t;
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void nes_ntsc_init_emph( nes_ntsc_emph_t* ntsc, nes_ntsc_setup_t const* setup );
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void nes_ntsc_blit_emph( nes_ntsc_emph_t const* ntsc, unsigned short const* nes_in,
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long in_row_width, int burst_phase, int in_width, int in_height,
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void* rgb_out, long out_pitch );
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/* Number of output pixels written by blitter for given input width. Width might
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be rounded down slightly; use NES_NTSC_IN_WIDTH() on result to find rounded
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value. Guaranteed not to round 256 down at all. */
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#define NES_NTSC_OUT_WIDTH( in_width ) \
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(((in_width) - 1) / nes_ntsc_in_chunk * nes_ntsc_out_chunk + nes_ntsc_out_chunk)
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/* Number of input pixels that will fit within given output width. Might be
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rounded down slightly; use NES_NTSC_OUT_WIDTH() on result to find rounded
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value. */
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#define NES_NTSC_IN_WIDTH( out_width ) \
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((out_width) / nes_ntsc_out_chunk * nes_ntsc_in_chunk - nes_ntsc_in_chunk + 1)
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/* Interface for user-defined custom blitters.
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Can be used with nes_ntsc_t and nes_ntsc_emph_t */
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enum { nes_ntsc_in_chunk = 3 }; /* number of input pixels read per chunk */
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enum { nes_ntsc_out_chunk = 7 }; /* number of output pixels generated per chunk */
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enum { nes_ntsc_black = 15 }; /* palette index for black */
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enum { nes_ntsc_burst_count = 3 }; /* burst phase cycles through 0, 1, and 2 */
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/* Begin outputting row and start three pixels. First pixel will be cut off a bit.
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Use nes_ntsc_black for unused pixels. Declares variables, so must be before first
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statement in a block (unless you're using C++). */
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#define NES_NTSC_BEGIN_ROW( ntsc, burst, pixel0, pixel1, pixel2 ) \
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char const* const ktable = \
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(char*) (ntsc)->table + burst * (nes_ntsc_burst_size * sizeof (ntsc_rgb_t));\
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NTSC_BEGIN_ROW_6_( pixel0, pixel1, pixel2, NES_NTSC_ENTRY_, ktable )
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/* Begin input pixel */
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#define NES_NTSC_COLOR_IN( in_index, color_in ) \
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NTSC_COLOR_IN_( in_index, color_in, NES_NTSC_ENTRY_, ktable )
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/* Generate output pixel. Bits can be 24, 16, 15, 32 (treated as 24), or 0:
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24: RRRRRRRR GGGGGGGG BBBBBBBB
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16: RRRRRGGG GGGBBBBB
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15: RRRRRGG GGGBBBBB
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0: xxxRRRRR RRRxxGGG GGGGGxxB BBBBBBBx (native internal format; x = junk bits) */
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#define NES_NTSC_RGB_OUT( index, rgb_out, bits ) \
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NTSC_RGB_OUT_14_( index, rgb_out, bits, 0 )
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/* private */
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enum { nes_ntsc_entry_size = 128 };
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typedef unsigned long ntsc_rgb_t;
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struct nes_ntsc_t {
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ntsc_rgb_t table [nes_ntsc_palette_size * nes_ntsc_entry_size];
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};
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struct nes_ntsc_emph_t {
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ntsc_rgb_t table [nes_ntsc_emph_palette_size * nes_ntsc_entry_size];
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};
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enum { nes_ntsc_burst_size = nes_ntsc_entry_size / nes_ntsc_burst_count };
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#define NES_NTSC_ENTRY_( ktable, n ) \
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(ntsc_rgb_t*) (ktable + (n) * (nes_ntsc_entry_size * sizeof (ntsc_rgb_t)))
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/* deprecated */
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#define NES_NTSC_RGB24_OUT( x, out ) NES_NTSC_RGB_OUT( x, out, 24 )
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#define NES_NTSC_RGB16_OUT( x, out ) NES_NTSC_RGB_OUT( x, out, 16 )
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#define NES_NTSC_RGB15_OUT( x, out ) NES_NTSC_RGB_OUT( x, out, 15 )
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#define NES_NTSC_RAW_OUT( x, out ) NES_NTSC_RGB_OUT( x, out, 0 )
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enum { nes_ntsc_min_in_width = 256 };
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enum { nes_ntsc_min_out_width = NES_NTSC_OUT_WIDTH( nes_ntsc_min_in_width ) };
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enum { nes_ntsc_640_in_width = 271 };
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enum { nes_ntsc_640_out_width = NES_NTSC_OUT_WIDTH( nes_ntsc_640_in_width ) };
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enum { nes_ntsc_640_overscan_left = 8 };
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enum { nes_ntsc_640_overscan_right = nes_ntsc_640_in_width - 256 - nes_ntsc_640_overscan_left };
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enum { nes_ntsc_full_in_width = 283 };
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enum { nes_ntsc_full_out_width = NES_NTSC_OUT_WIDTH( nes_ntsc_full_in_width ) };
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enum { nes_ntsc_full_overscan_left = 16 };
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enum { nes_ntsc_full_overscan_right = nes_ntsc_full_in_width - 256 - nes_ntsc_full_overscan_left };
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/* common 3->7 ntsc macros */
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#define NTSC_BEGIN_ROW_6_( pixel0, pixel1, pixel2, ENTRY, table ) \
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unsigned const ntsc_pixel0_ = (pixel0);\
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ntsc_rgb_t const* kernel0 = ENTRY( table, ntsc_pixel0_ );\
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unsigned const ntsc_pixel1_ = (pixel1);\
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ntsc_rgb_t const* kernel1 = ENTRY( table, ntsc_pixel1_ );\
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unsigned const ntsc_pixel2_ = (pixel2);\
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ntsc_rgb_t const* kernel2 = ENTRY( table, ntsc_pixel2_ );\
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ntsc_rgb_t const* kernelx0;\
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ntsc_rgb_t const* kernelx1 = kernel0;\
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ntsc_rgb_t const* kernelx2 = kernel0
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#define NTSC_RGB_OUT_14_( x, rgb_out, bits, shift ) {\
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ntsc_rgb_t raw_ =\
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kernel0 [x ] + kernel1 [(x+12)%7+14] + kernel2 [(x+10)%7+28] +\
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kernelx0 [(x+7)%14] + kernelx1 [(x+ 5)%7+21] + kernelx2 [(x+ 3)%7+35];\
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NTSC_CLAMP_( raw_, shift );\
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NTSC_RGB_OUT_( rgb_out, bits, shift );\
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}
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/* common ntsc macros */
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#define ntsc_rgb_builder ((1L << 21) | (1 << 11) | (1 << 1))
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#define ntsc_clamp_mask (ntsc_rgb_builder * 3 / 2)
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#define ntsc_clamp_add (ntsc_rgb_builder * 0x101)
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#define NTSC_CLAMP_( io, shift ) {\
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ntsc_rgb_t sub = (io) >> (9-(shift)) & ntsc_clamp_mask;\
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ntsc_rgb_t clamp = ntsc_clamp_add - sub;\
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io |= clamp;\
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clamp -= sub;\
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io &= clamp;\
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}
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#define NTSC_COLOR_IN_( index, color, ENTRY, table ) {\
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unsigned color_;\
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kernelx##index = kernel##index;\
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kernel##index = (color_ = (color), ENTRY( table, color_ ));\
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}
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/* x is always zero except in snes_ntsc library */
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#define NTSC_RGB_OUT_( rgb_out, bits, x ) {\
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if ( bits == 16 )\
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rgb_out = (raw_>>(13-x)& 0xF800)|(raw_>>(8-x)&0x07E0)|(raw_>>(4-x)&0x001F);\
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if ( bits == 24 || bits == 32 )\
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rgb_out = (raw_>>(5-x)&0xFF0000)|(raw_>>(3-x)&0xFF00)|(raw_>>(1-x)&0xFF);\
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if ( bits == 15 )\
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rgb_out = (raw_>>(14-x)& 0x7C00)|(raw_>>(9-x)&0x03E0)|(raw_>>(4-x)&0x001F);\
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if ( bits == 14 )\
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rgb_out = (raw_>>(24-x)& 0x001F)|(raw_>>(9-x)&0x03E0)|(raw_<<(6+x)&0x7C00);\
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if ( bits == 0 )\
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rgb_out = raw_ << x;\
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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