ref: ffb988cdecd7c2d0ef84290ecde8da6be539f55b
dir: /src/i_scale.c/
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005-2014 Simon Howard
//
// 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 (at your option) 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.
//
// DESCRIPTION:
// Screen scale-up code:
// 1x,2x,3x,4x pixel doubling
// Aspect ratio-correcting stretch functions
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "doomtype.h"
#include "i_video.h"
#include "m_argv.h"
#include "z_zone.h"
// Should be I_VideoBuffer
static byte *src_buffer;
// Destination buffer, ie. screen->pixels.
static byte *dest_buffer;
// Pitch of destination buffer, ie. screen->pitch.
static int dest_pitch;
// Lookup tables used for aspect ratio correction stretching code.
// stretch_tables[0] : 20% / 80%
// stretch_tables[1] : 40% / 60%
// All other combinations can be reached from these two tables.
static byte *stretch_tables[2] = { NULL, NULL };
// 50%/50% stretch table, for 800x600 squash mode
static byte *half_stretch_table = NULL;
// Called to set the source and destination buffers before doing the
// scale.
void I_InitScale(byte *_src_buffer, byte *_dest_buffer, int _dest_pitch)
{
src_buffer = _src_buffer;
dest_buffer = _dest_buffer;
dest_pitch = _dest_pitch;
}
//
// Pixel doubling scale-up functions.
//
// 1x scale doesn't really do any scaling: it just copies the buffer
// a line at a time for when pitch != SCREENWIDTH (!native_surface)
static boolean I_Scale1x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
int w = x2 - x1;
// Need to byte-copy from buffer into the screen buffer
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + y1 * dest_pitch + x1;
for (y=y1; y<y2; ++y)
{
memcpy(screenp, bufp, w);
screenp += dest_pitch;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_scale_1x = {
SCREENWIDTH, SCREENHEIGHT,
NULL,
I_Scale1x,
false,
};
// 2x scale (640x400)
static boolean I_Scale2x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp, *screenp2;
int x, y;
int multi_pitch;
multi_pitch = dest_pitch * 2;
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + (y1 * dest_pitch + x1) * 2;
screenp2 = screenp + dest_pitch;
for (y=y1; y<y2; ++y)
{
byte *sp, *sp2, *bp;
sp = screenp;
sp2 = screenp2;
bp = bufp;
for (x=x1; x<x2; ++x)
{
*sp++ = *bp; *sp++ = *bp;
*sp2++ = *bp; *sp2++ = *bp;
++bp;
}
screenp += multi_pitch;
screenp2 += multi_pitch;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_scale_2x = {
SCREENWIDTH * 2, SCREENHEIGHT * 2,
NULL,
I_Scale2x,
false,
};
// 3x scale (960x600)
static boolean I_Scale3x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp, *screenp2, *screenp3;
int x, y;
int multi_pitch;
multi_pitch = dest_pitch * 3;
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + (y1 * dest_pitch + x1) * 3;
screenp2 = screenp + dest_pitch;
screenp3 = screenp + dest_pitch * 2;
for (y=y1; y<y2; ++y)
{
byte *sp, *sp2, *sp3, *bp;
sp = screenp;
sp2 = screenp2;
sp3 = screenp3;
bp = bufp;
for (x=x1; x<x2; ++x)
{
*sp++ = *bp; *sp++ = *bp; *sp++ = *bp;
*sp2++ = *bp; *sp2++ = *bp; *sp2++ = *bp;
*sp3++ = *bp; *sp3++ = *bp; *sp3++ = *bp;
++bp;
}
screenp += multi_pitch;
screenp2 += multi_pitch;
screenp3 += multi_pitch;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_scale_3x = {
SCREENWIDTH * 3, SCREENHEIGHT * 3,
NULL,
I_Scale3x,
false,
};
// 4x scale (1280x800)
static boolean I_Scale4x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp, *screenp2, *screenp3, *screenp4;
int x, y;
int multi_pitch;
multi_pitch = dest_pitch * 4;
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + (y1 * dest_pitch + x1) * 4;
screenp2 = screenp + dest_pitch;
screenp3 = screenp + dest_pitch * 2;
screenp4 = screenp + dest_pitch * 3;
for (y=y1; y<y2; ++y)
{
byte *sp, *sp2, *sp3, *sp4, *bp;
sp = screenp;
sp2 = screenp2;
sp3 = screenp3;
sp4 = screenp4;
bp = bufp;
for (x=x1; x<x2; ++x)
{
*sp++ = *bp; *sp++ = *bp; *sp++ = *bp; *sp++ = *bp;
*sp2++ = *bp; *sp2++ = *bp; *sp2++ = *bp; *sp2++ = *bp;
*sp3++ = *bp; *sp3++ = *bp; *sp3++ = *bp; *sp3++ = *bp;
*sp4++ = *bp; *sp4++ = *bp; *sp4++ = *bp; *sp4++ = *bp;
++bp;
}
screenp += multi_pitch;
screenp2 += multi_pitch;
screenp3 += multi_pitch;
screenp4 += multi_pitch;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_scale_4x = {
SCREENWIDTH * 4, SCREENHEIGHT * 4,
NULL,
I_Scale4x,
false,
};
// 5x scale (1600x1000)
static boolean I_Scale5x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp, *screenp2, *screenp3, *screenp4, *screenp5;
int x, y;
int multi_pitch;
multi_pitch = dest_pitch * 5;
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + (y1 * dest_pitch + x1) * 5;
screenp2 = screenp + dest_pitch;
screenp3 = screenp + dest_pitch * 2;
screenp4 = screenp + dest_pitch * 3;
screenp5 = screenp + dest_pitch * 4;
for (y=y1; y<y2; ++y)
{
byte *sp, *sp2, *sp3, *sp4, *sp5, *bp;
sp = screenp;
sp2 = screenp2;
sp3 = screenp3;
sp4 = screenp4;
sp5 = screenp5;
bp = bufp;
for (x=x1; x<x2; ++x)
{
*sp++ = *bp; *sp++ = *bp; *sp++ = *bp; *sp++ = *bp; *sp++ = *bp;
*sp2++ = *bp; *sp2++ = *bp; *sp2++ = *bp; *sp2++ = *bp; *sp2++ = *bp;
*sp3++ = *bp; *sp3++ = *bp; *sp3++ = *bp; *sp3++ = *bp; *sp3++ = *bp;
*sp4++ = *bp; *sp4++ = *bp; *sp4++ = *bp; *sp4++ = *bp; *sp4++ = *bp;
*sp5++ = *bp; *sp5++ = *bp; *sp5++ = *bp; *sp5++ = *bp; *sp5++ = *bp;
++bp;
}
screenp += multi_pitch;
screenp2 += multi_pitch;
screenp3 += multi_pitch;
screenp4 += multi_pitch;
screenp5 += multi_pitch;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_scale_5x = {
SCREENWIDTH * 5, SCREENHEIGHT * 5,
NULL,
I_Scale5x,
false,
};
// Search through the given palette, finding the nearest color that matches
// the given color.
static int FindNearestColor(byte *palette, int r, int g, int b)
{
byte *col;
int best;
int best_diff;
int diff;
int i;
best = 0;
best_diff = INT_MAX;
for (i=0; i<256; ++i)
{
col = palette + i * 3;
diff = (r - col[0]) * (r - col[0])
+ (g - col[1]) * (g - col[1])
+ (b - col[2]) * (b - col[2]);
if (diff == 0)
{
return i;
}
else if (diff < best_diff)
{
best = i;
best_diff = diff;
}
}
return best;
}
// Create a stretch table. This is a lookup table for blending colors.
// pct specifies the bias between the two colors: 0 = all y, 100 = all x.
// NB: This is identical to the lookup tables used in other ports for
// translucency.
static byte *GenerateStretchTable(byte *palette, int pct)
{
byte *result;
int x, y;
int r, g, b;
byte *col1;
byte *col2;
result = Z_Malloc(256 * 256, PU_STATIC, NULL);
for (x=0; x<256; ++x)
{
for (y=0; y<256; ++y)
{
col1 = palette + x * 3;
col2 = palette + y * 3;
r = (((int) col1[0]) * pct + ((int) col2[0]) * (100 - pct)) / 100;
g = (((int) col1[1]) * pct + ((int) col2[1]) * (100 - pct)) / 100;
b = (((int) col1[2]) * pct + ((int) col2[2]) * (100 - pct)) / 100;
result[x * 256 + y] = FindNearestColor(palette, r, g, b);
}
}
return result;
}
// Called at startup to generate the lookup tables for aspect ratio
// correcting scale up.
static void I_InitStretchTables(byte *palette)
{
if (stretch_tables[0] != NULL)
{
return;
}
// We only actually need two lookup tables:
//
// mix 0% = just write line 1
// mix 20% = stretch_tables[0]
// mix 40% = stretch_tables[1]
// mix 60% = stretch_tables[1] used backwards
// mix 80% = stretch_tables[0] used backwards
// mix 100% = just write line 2
printf("I_InitStretchTables: Generating lookup tables..");
fflush(stdout);
stretch_tables[0] = GenerateStretchTable(palette, 20);
printf(".."); fflush(stdout);
stretch_tables[1] = GenerateStretchTable(palette, 40);
puts("");
}
// Create 50%/50% table for 800x600 squash mode
static void I_InitSquashTable(byte *palette)
{
if (half_stretch_table != NULL)
{
return;
}
printf("I_InitSquashTable: Generating lookup table..");
fflush(stdout);
half_stretch_table = GenerateStretchTable(palette, 50);
puts("");
}
// Destroy the scaling lookup tables. This should only ever be called
// if switching to a completely different palette from the normal one
// (in which case the mappings no longer make any sense).
void I_ResetScaleTables(byte *palette)
{
if (stretch_tables[0] != NULL)
{
Z_Free(stretch_tables[0]);
Z_Free(stretch_tables[1]);
printf("I_ResetScaleTables: Regenerating lookup tables..\n");
stretch_tables[0] = GenerateStretchTable(palette, 20);
stretch_tables[1] = GenerateStretchTable(palette, 40);
}
if (half_stretch_table != NULL)
{
Z_Free(half_stretch_table);
printf("I_ResetScaleTables: Regenerating lookup table..\n");
half_stretch_table = GenerateStretchTable(palette, 50);
}
}
//
// Aspect ratio correcting scale up functions.
//
// These double up pixels to stretch the screen when using a 4:3
// screen mode.
//
static inline void WriteBlendedLine1x(byte *dest, byte *src1, byte *src2,
byte *stretch_table)
{
int x;
for (x=0; x<SCREENWIDTH; ++x)
{
*dest = stretch_table[*src1 * 256 + *src2];
++dest;
++src1;
++src2;
}
}
// 1x stretch (320x240)
static boolean I_Stretch1x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
// Need to byte-copy from buffer into the screen buffer
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + y1 * dest_pitch + x1;
// For every 5 lines of src_buffer, 6 lines are written to dest_buffer
// (200 -> 240)
for (y=0; y<SCREENHEIGHT; y += 5)
{
// 100% line 0
memcpy(screenp, bufp, SCREENWIDTH);
screenp += dest_pitch;
// 20% line 0, 80% line 1
WriteBlendedLine1x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 40% line 1, 60% line 2
WriteBlendedLine1x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 60% line 2, 40% line 3
WriteBlendedLine1x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 80% line 3, 20% line 4
WriteBlendedLine1x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 4
memcpy(screenp, bufp, SCREENWIDTH);
screenp += dest_pitch; bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_stretch_1x = {
SCREENWIDTH, SCREENHEIGHT_4_3,
I_InitStretchTables,
I_Stretch1x,
true,
};
static inline void WriteLine2x(byte *dest, byte *src)
{
int x;
for (x=0; x<SCREENWIDTH; ++x)
{
dest[0] = *src;
dest[1] = *src;
dest += 2;
++src;
}
}
static inline void WriteBlendedLine2x(byte *dest, byte *src1, byte *src2,
byte *stretch_table)
{
int x;
int val;
for (x=0; x<SCREENWIDTH; ++x)
{
val = stretch_table[*src1 * 256 + *src2];
dest[0] = val;
dest[1] = val;
dest += 2;
++src1;
++src2;
}
}
// 2x stretch (640x480)
static boolean I_Stretch2x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
// Need to byte-copy from buffer into the screen buffer
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + y1 * dest_pitch + x1;
// For every 5 lines of src_buffer, 12 lines are written to dest_buffer.
// (200 -> 480)
for (y=0; y<SCREENHEIGHT; y += 5)
{
// 100% line 0
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 40% line 0, 60% line 1
WriteBlendedLine2x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 1
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 80% line 1, 20% line 2
WriteBlendedLine2x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 2
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 100% line 2
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 20% line 2, 80% line 3
WriteBlendedLine2x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 3
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 60% line 3, 40% line 4
WriteBlendedLine2x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 4
WriteLine2x(screenp, bufp);
screenp += dest_pitch;
// 100% line 4
WriteLine2x(screenp, bufp);
screenp += dest_pitch; bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_stretch_2x = {
SCREENWIDTH * 2, SCREENHEIGHT_4_3 * 2,
I_InitStretchTables,
I_Stretch2x,
false,
};
static inline void WriteLine3x(byte *dest, byte *src)
{
int x;
for (x=0; x<SCREENWIDTH; ++x)
{
dest[0] = *src;
dest[1] = *src;
dest[2] = *src;
dest += 3;
++src;
}
}
static inline void WriteBlendedLine3x(byte *dest, byte *src1, byte *src2,
byte *stretch_table)
{
int x;
int val;
for (x=0; x<SCREENWIDTH; ++x)
{
val = stretch_table[*src1 * 256 + *src2];
dest[0] = val;
dest[1] = val;
dest[2] = val;
dest += 3;
++src1;
++src2;
}
}
// 3x stretch (960x720)
static boolean I_Stretch3x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
// Need to byte-copy from buffer into the screen buffer
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + y1 * dest_pitch + x1;
// For every 5 lines of src_buffer, 18 lines are written to dest_buffer.
// (200 -> 720)
for (y=0; y<SCREENHEIGHT; y += 5)
{
// 100% line 0
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 60% line 0, 40% line 1
WriteBlendedLine3x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 1
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 1
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 1
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 20% line 1, 80% line 2
WriteBlendedLine3x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 2
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 2
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 80% line 2, 20% line 3
WriteBlendedLine3x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 3
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 3
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 3
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 40% line 3, 60% line 4
WriteBlendedLine3x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 4
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 4
WriteLine3x(screenp, bufp);
screenp += dest_pitch;
// 100% line 4
WriteLine3x(screenp, bufp);
screenp += dest_pitch; bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_stretch_3x = {
SCREENWIDTH * 3, SCREENHEIGHT_4_3 * 3,
I_InitStretchTables,
I_Stretch3x,
false,
};
static inline void WriteLine4x(byte *dest, byte *src)
{
int x;
for (x=0; x<SCREENWIDTH; ++x)
{
dest[0] = *src;
dest[1] = *src;
dest[2] = *src;
dest[3] = *src;
dest += 4;
++src;
}
}
static inline void WriteBlendedLine4x(byte *dest, byte *src1, byte *src2,
byte *stretch_table)
{
int x;
int val;
for (x=0; x<SCREENWIDTH; ++x)
{
val = stretch_table[*src1 * 256 + *src2];
dest[0] = val;
dest[1] = val;
dest[2] = val;
dest[3] = val;
dest += 4;
++src1;
++src2;
}
}
// 4x stretch (1280x960)
static boolean I_Stretch4x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
// Need to byte-copy from buffer into the screen buffer
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + y1 * dest_pitch + x1;
// For every 5 lines of src_buffer, 24 lines are written to dest_buffer.
// (200 -> 960)
for (y=0; y<SCREENHEIGHT; y += 5)
{
// 100% line 0
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 90% line 0, 20% line 1
WriteBlendedLine4x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 1
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 1
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 1
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 1
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 60% line 1, 40% line 2
WriteBlendedLine4x(screenp, bufp + SCREENWIDTH, bufp, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 2
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 2
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 2
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 2
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 40% line 2, 60% line 3
WriteBlendedLine4x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[1]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 3
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 3
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 3
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 3
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 20% line 3, 80% line 4
WriteBlendedLine4x(screenp, bufp, bufp + SCREENWIDTH, stretch_tables[0]);
screenp += dest_pitch; bufp += SCREENWIDTH;
// 100% line 4
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 4
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 4
WriteLine4x(screenp, bufp);
screenp += dest_pitch;
// 100% line 4
WriteLine4x(screenp, bufp);
screenp += dest_pitch; bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_stretch_4x = {
SCREENWIDTH * 4, SCREENHEIGHT_4_3 * 4,
I_InitStretchTables,
I_Stretch4x,
false,
};
static inline void WriteLine5x(byte *dest, byte *src)
{
int x;
for (x=0; x<SCREENWIDTH; ++x)
{
dest[0] = *src;
dest[1] = *src;
dest[2] = *src;
dest[3] = *src;
dest[4] = *src;
dest += 5;
++src;
}
}
// 5x stretch (1600x1200)
static boolean I_Stretch5x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
// Need to byte-copy from buffer into the screen buffer
bufp = src_buffer + y1 * SCREENWIDTH + x1;
screenp = (byte *) dest_buffer + y1 * dest_pitch + x1;
// For every 1 line of src_buffer, 6 lines are written to dest_buffer.
// (200 -> 1200)
for (y=0; y<SCREENHEIGHT; y += 1)
{
// 100% line 0
WriteLine5x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine5x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine5x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine5x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine5x(screenp, bufp);
screenp += dest_pitch;
// 100% line 0
WriteLine5x(screenp, bufp);
screenp += dest_pitch; bufp += SCREENWIDTH;
}
// test hack for Porsche Monty... scan line simulation:
// See here: https://www.doomworld.com/vb/post/962612
if (M_CheckParm("-scanline") > 0)
{
screenp = (byte *) dest_buffer + 2 * dest_pitch;
for (y=0; y<1198; y += 3)
{
memset(screenp, 0, 1600);
screenp += dest_pitch * 3;
}
}
return true;
}
screen_mode_t mode_stretch_5x = {
SCREENWIDTH * 5, SCREENHEIGHT_4_3 * 5,
I_InitStretchTables,
I_Stretch5x,
false,
};
//
// Aspect ratio correcting "squash" functions.
//
// These do the opposite of the "stretch" functions above: while the
// stretch functions increase the vertical dimensions, the squash
// functions decrease the horizontal dimensions for the same result.
//
// The same blend tables from the stretch functions are reused; as
// a result, the dimensions are *slightly* wrong (eg. 320x200 should
// squash to 266x200, but actually squashes to 256x200).
//
//
// 1x squashed scale (256x200)
//
static inline void WriteSquashedLine1x(byte *dest, byte *src)
{
int x;
for (x=0; x<SCREENWIDTH; )
{
// Draw in blocks of 5
// 80% pixel 0, 20% pixel 1
*dest++ = stretch_tables[0][src[1] * 256 + src[0]];
// 60% pixel 1, 40% pixel 2
*dest++ = stretch_tables[1][src[2] * 256 + src[1]];
// 40% pixel 2, 60% pixel 3
*dest++ = stretch_tables[1][src[2] * 256 + src[3]];
// 20% pixel 3, 80% pixel 4
*dest++ = stretch_tables[0][src[3] * 256 + src[4]];
x += 5;
src += 5;
}
}
// 1x squashed (256x200)
static boolean I_Squash1x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
bufp = src_buffer;
screenp = (byte *) dest_buffer;
for (y=0; y<SCREENHEIGHT; ++y)
{
WriteSquashedLine1x(screenp, bufp);
screenp += dest_pitch;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_squash_1x = {
SCREENWIDTH_4_3, SCREENHEIGHT,
I_InitStretchTables,
I_Squash1x,
true,
};
//
// 2x squashed scale (512x400)
//
#define DRAW_PIXEL2 \
*dest++ = *dest2++ = c;
static inline void WriteSquashedLine2x(byte *dest, byte *src)
{
byte *dest2;
int x, c;
dest2 = dest + dest_pitch;
for (x=0; x<SCREENWIDTH; )
{
// Draw in blocks of 5
// 100% pixel 0
c = src[0];
DRAW_PIXEL2;
// 60% pixel 0, 40% pixel 1
c = stretch_tables[1][src[1] * 256 + src[0]];
DRAW_PIXEL2;
// 100% pixel 1
c = src[1];
DRAW_PIXEL2;
// 20% pixel 1, 80% pixel 2
c = stretch_tables[0][src[1] * 256 + src[2]];
DRAW_PIXEL2;
// 80% pixel 2, 20% pixel 3
c = stretch_tables[0][src[3] * 256 + src[2]];
DRAW_PIXEL2;
// 100% pixel 3
c = src[3];
DRAW_PIXEL2;
// 40% pixel 3, 60% pixel 4
c = stretch_tables[1][src[3] * 256 + src[4]];
DRAW_PIXEL2;
// 100% pixel 4
c = src[4];
DRAW_PIXEL2;
x += 5;
src += 5;
}
}
// 2x squash (512x400)
static boolean I_Squash2x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
bufp = src_buffer;
screenp = (byte *) dest_buffer;
for (y=0; y<SCREENHEIGHT; ++y)
{
WriteSquashedLine2x(screenp, bufp);
screenp += dest_pitch * 2;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_squash_2x = {
SCREENWIDTH_4_3 * 2, SCREENHEIGHT * 2,
I_InitStretchTables,
I_Squash2x,
false,
};
#define DRAW_PIXEL3 \
*dest++ = *dest2++ = *dest3++ = c
static inline void WriteSquashedLine3x(byte *dest, byte *src)
{
byte *dest2, *dest3;
int x, c;
dest2 = dest + dest_pitch;
dest3 = dest + dest_pitch * 2;
for (x=0; x<SCREENWIDTH; )
{
// Every 2 pixels is expanded to 5 pixels
// 100% pixel 0 x2
c = src[0];
DRAW_PIXEL3;
DRAW_PIXEL3;
// 50% pixel 0, 50% pixel 1
c = half_stretch_table[src[0] * 256 + src[1]];
DRAW_PIXEL3;
// 100% pixel 1
c = src[1];
DRAW_PIXEL3;
DRAW_PIXEL3;
x += 2;
src += 2;
}
}
//
// 3x scale squashed (800x600)
//
// This is a special case that uses the half_stretch_table (50%) rather
// than the normal stretch_tables(20,40%), to scale up to 800x600
// exactly.
//
static boolean I_Squash3x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
bufp = src_buffer;
screenp = (byte *) dest_buffer;
for (y=0; y<SCREENHEIGHT; ++y)
{
WriteSquashedLine3x(screenp, bufp);
screenp += dest_pitch * 3;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_squash_3x = {
800, 600,
I_InitSquashTable,
I_Squash3x,
false,
};
#define DRAW_PIXEL4 \
*dest++ = *dest2++ = *dest3++ = *dest4++ = c;
static inline void WriteSquashedLine4x(byte *dest, byte *src)
{
int x;
int c;
byte *dest2, *dest3, *dest4;
dest2 = dest + dest_pitch;
dest3 = dest + dest_pitch * 2;
dest4 = dest + dest_pitch * 3;
for (x=0; x<SCREENWIDTH; )
{
// Draw in blocks of 5
// 100% pixel 0 x3
c = src[0];
DRAW_PIXEL4;
DRAW_PIXEL4;
DRAW_PIXEL4;
// 20% pixel 0, 80% pixel 1
c = stretch_tables[0][src[0] * 256 + src[1]];
DRAW_PIXEL4;
// 100% pixel 1 x2
c = src[1];
DRAW_PIXEL4;
DRAW_PIXEL4;
// 40% pixel 1, 60% pixel 2
c = stretch_tables[1][src[1] * 256 + src[2]];
DRAW_PIXEL4;
// 100% pixel 2 x2
c = src[2];
DRAW_PIXEL4;
DRAW_PIXEL4;
// 60% pixel 2, 40% pixel 3
c = stretch_tables[1][src[3] * 256 + src[2]];
DRAW_PIXEL4;
// 100% pixel 3 x2
c = src[3];
DRAW_PIXEL4;
DRAW_PIXEL4;
// 80% pixel 3, 20% pixel 4
c = stretch_tables[0][src[4] * 256 + src[3]];
DRAW_PIXEL4;
// 100% pixel 4
c = src[4];
DRAW_PIXEL4;
DRAW_PIXEL4;
DRAW_PIXEL4;
x += 5;
src += 5;
}
}
//
// 4x squashed (1024x800)
//
static boolean I_Squash4x(int x1, int y1, int x2, int y2)
{
byte *bufp, *screenp;
int y;
// Only works with full screen update
if (x1 != 0 || y1 != 0 || x2 != SCREENWIDTH || y2 != SCREENHEIGHT)
{
return false;
}
bufp = src_buffer;
screenp = (byte *) dest_buffer;
for (y=0; y<SCREENHEIGHT; ++y)
{
WriteSquashedLine4x(screenp, bufp);
screenp += dest_pitch * 4;
bufp += SCREENWIDTH;
}
return true;
}
screen_mode_t mode_squash_4x = {
SCREENWIDTH_4_3 * 4, SCREENHEIGHT * 4,
I_InitStretchTables,
I_Squash4x,
false,
};
// We used to have mode_squash_5x here as well, but it got removed.
// 5x squashing gives 1280x1000, which is very close to the 4x stretched
// 1280x960. The difference is that 1280x1000 is the wrong aspect ratio.
// It was ultimately decided that it was better to use the right aspect
// ratio and have slightly larger borders than to have slightly smaller
// windowboxing borders. It also means that the aspect ratio is correct
// when running at 1280x1024. See bug #460 for more details, or this
// post: https://www.doomworld.com/vb/post/1316735