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SDL_draw.h
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2010 Sam Lantinga
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This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
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#include "../../video/SDL_blit.h"
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/* This code assumes that r, g, b, a are the source color,
* and in the blend and add case, the RGB values are premultiplied by a.
*/
#define DRAW_MUL(_a, _b) (((unsigned)(_a)*(_b))/255)
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#define DRAW_FASTSETPIXEL(type) \
*pixel = (type) color
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#define DRAW_FASTSETPIXEL1 DRAW_FASTSETPIXEL(Uint8)
#define DRAW_FASTSETPIXEL2 DRAW_FASTSETPIXEL(Uint16)
#define DRAW_FASTSETPIXEL4 DRAW_FASTSETPIXEL(Uint32)
#define DRAW_FASTSETPIXELXY(x, y, type, bpp, color) \
*(type *)((Uint8 *)dst->pixels + (y) * dst->pitch \
+ (x) * bpp) = (type) color
#define DRAW_FASTSETPIXELXY1(x, y) DRAW_FASTSETPIXELXY(x, y, Uint8, 1, color)
#define DRAW_FASTSETPIXELXY2(x, y) DRAW_FASTSETPIXELXY(x, y, Uint16, 2, color)
#define DRAW_FASTSETPIXELXY4(x, y) DRAW_FASTSETPIXELXY(x, y, Uint32, 4, color)
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#define DRAW_SETPIXEL(setpixel) \
do { \
unsigned sr = r, sg = g, sb = b, sa = a; \
setpixel; \
} while (0)
#define DRAW_SETPIXEL_BLEND(getpixel, setpixel) \
do { \
unsigned sr, sg, sb, sa; sa; \
getpixel; \
sr = DRAW_MUL(inva, sr) + r; \
sg = DRAW_MUL(inva, sg) + g; \
sb = DRAW_MUL(inva, sb) + b; \
setpixel; \
} while (0)
#define DRAW_SETPIXEL_ADD(getpixel, setpixel) \
do { \
unsigned sr, sg, sb, sa; sa; \
getpixel; \
sr += r; if (sr > 0xff) sr = 0xff; \
sg += g; if (sg > 0xff) sg = 0xff; \
sb += b; if (sb > 0xff) sb = 0xff; \
setpixel; \
} while (0)
#define DRAW_SETPIXELXY(x, y, type, bpp, op) \
do { \
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type *pixel = (type *)((Uint8 *)dst->pixels + (y) * dst->pitch \
+ (x) * bpp); \
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op; \
} while (0)
/*
* Define draw operators for RGB555
*/
#define DRAW_SETPIXEL_RGB555 \
DRAW_SETPIXEL(RGB555_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXEL_BLEND_RGB555 \
DRAW_SETPIXEL_BLEND(RGB_FROM_RGB555(*pixel, sr, sg, sb), \
RGB555_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXEL_ADD_RGB555 \
DRAW_SETPIXEL_ADD(RGB_FROM_RGB555(*pixel, sr, sg, sb), \
RGB555_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXELXY_RGB555(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_RGB555)
#define DRAW_SETPIXELXY_BLEND_RGB555(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_BLEND_RGB555)
#define DRAW_SETPIXELXY_ADD_RGB555(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_ADD_RGB555)
/*
* Define draw operators for RGB565
*/
#define DRAW_SETPIXEL_RGB565 \
DRAW_SETPIXEL(RGB565_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXEL_BLEND_RGB565 \
DRAW_SETPIXEL_BLEND(RGB_FROM_RGB565(*pixel, sr, sg, sb), \
RGB565_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXEL_ADD_RGB565 \
DRAW_SETPIXEL_ADD(RGB_FROM_RGB565(*pixel, sr, sg, sb), \
RGB565_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXELXY_RGB565(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_RGB565)
#define DRAW_SETPIXELXY_BLEND_RGB565(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_BLEND_RGB565)
#define DRAW_SETPIXELXY_ADD_RGB565(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_ADD_RGB565)
/*
* Define draw operators for RGB888
*/
#define DRAW_SETPIXEL_RGB888 \
DRAW_SETPIXEL(RGB888_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXEL_BLEND_RGB888 \
DRAW_SETPIXEL_BLEND(RGB_FROM_RGB888(*pixel, sr, sg, sb), \
RGB888_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXEL_ADD_RGB888 \
DRAW_SETPIXEL_ADD(RGB_FROM_RGB888(*pixel, sr, sg, sb), \
RGB888_FROM_RGB(*pixel, sr, sg, sb))
#define DRAW_SETPIXELXY_RGB888(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_RGB888)
#define DRAW_SETPIXELXY_BLEND_RGB888(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_BLEND_RGB888)
#define DRAW_SETPIXELXY_ADD_RGB888(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_ADD_RGB888)
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/*
* Define draw operators for ARGB8888
*/
#define DRAW_SETPIXEL_ARGB8888 \
DRAW_SETPIXEL(ARGB8888_FROM_RGBA(*pixel, sr, sg, sb, sa))
#define DRAW_SETPIXEL_BLEND_ARGB8888 \
DRAW_SETPIXEL_BLEND(RGBA_FROM_ARGB8888(*pixel, sr, sg, sb, sa), \
ARGB8888_FROM_RGBA(*pixel, sr, sg, sb, sa))
#define DRAW_SETPIXEL_ADD_ARGB8888 \
DRAW_SETPIXEL_ADD(RGBA_FROM_ARGB8888(*pixel, sr, sg, sb, sa), \
ARGB8888_FROM_RGBA(*pixel, sr, sg, sb, sa))
#define DRAW_SETPIXELXY_ARGB8888(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_ARGB8888)
#define DRAW_SETPIXELXY_BLEND_ARGB8888(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_BLEND_ARGB8888)
#define DRAW_SETPIXELXY_ADD_ARGB8888(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_ADD_ARGB8888)
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/*
* Define draw operators for general RGB
*/
#define DRAW_SETPIXEL_RGB \
DRAW_SETPIXEL(PIXEL_FROM_RGB(*pixel, fmt, sr, sg, sb))
#define DRAW_SETPIXEL_BLEND_RGB \
DRAW_SETPIXEL_BLEND(RGB_FROM_PIXEL(*pixel, fmt, sr, sg, sb), \
PIXEL_FROM_RGB(*pixel, fmt, sr, sg, sb))
#define DRAW_SETPIXEL_ADD_RGB \
DRAW_SETPIXEL_ADD(RGB_FROM_PIXEL(*pixel, fmt, sr, sg, sb), \
PIXEL_FROM_RGB(*pixel, fmt, sr, sg, sb))
#define DRAW_SETPIXELXY2_RGB(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_RGB)
#define DRAW_SETPIXELXY4_RGB(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_RGB)
#define DRAW_SETPIXELXY2_BLEND_RGB(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_BLEND_RGB)
#define DRAW_SETPIXELXY4_BLEND_RGB(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_BLEND_RGB)
#define DRAW_SETPIXELXY2_ADD_RGB(x, y) \
DRAW_SETPIXELXY(x, y, Uint16, 2, DRAW_SETPIXEL_ADD_RGB)
#define DRAW_SETPIXELXY4_ADD_RGB(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_ADD_RGB)
/*
* Define draw operators for general RGBA
*/
#define DRAW_SETPIXEL_RGBA \
DRAW_SETPIXEL(PIXEL_FROM_RGBA(*pixel, fmt, sr, sg, sb, sa))
#define DRAW_SETPIXEL_BLEND_RGBA \
DRAW_SETPIXEL_BLEND(RGBA_FROM_PIXEL(*pixel, fmt, sr, sg, sb, sa), \
PIXEL_FROM_RGBA(*pixel, fmt, sr, sg, sb, sa))
#define DRAW_SETPIXEL_ADD_RGBA \
DRAW_SETPIXEL_ADD(RGBA_FROM_PIXEL(*pixel, fmt, sr, sg, sb, sa), \
PIXEL_FROM_RGBA(*pixel, fmt, sr, sg, sb, sa))
#define DRAW_SETPIXELXY4_RGBA(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_RGBA)
#define DRAW_SETPIXELXY4_BLEND_RGBA(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_BLEND_RGBA)
#define DRAW_SETPIXELXY4_ADD_RGBA(x, y) \
DRAW_SETPIXELXY(x, y, Uint32, 4, DRAW_SETPIXEL_ADD_RGBA)
/*
* Define line drawing macro
*/
#define ABS(_x) ((_x) < 0 ? -(_x) : (_x))
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/* Horizontal line */
#define HLINE(type, op, draw_end) \
{ \
int length; \
int pitch = (dst->pitch / dst->format->BytesPerPixel); \
type *pixel; \
if (x1 <= x2) { \
pixel = (type *)dst->pixels + y1 * pitch + x1; \
length = draw_end ? (x2-x1+1) : (x2-x1); \
} else { \
pixel = (type *)dst->pixels + y1 * pitch + x2; \
if (!draw_end) { \
++pixel; \
} \
length = draw_end ? (x1-x2+1) : (x1-x2); \
} \
while (length--) { \
op; \
++pixel; \
} \
}
/* Vertical line */
#define VLINE(type, op, draw_end) \
{ \
int length; \
int pitch = (dst->pitch / dst->format->BytesPerPixel); \
type *pixel; \
if (y1 <= y2) { \
pixel = (type *)dst->pixels + y1 * pitch + x1; \
length = draw_end ? (y2-y1+1) : (y2-y1); \
} else { \
pixel = (type *)dst->pixels + y2 * pitch + x1; \
if (!draw_end) { \
pixel += pitch; \
} \
length = draw_end ? (y1-y2+1) : (y1-y2); \
} \
while (length--) { \
op; \
pixel += pitch; \
} \
}
/* Diagonal line */
#define DLINE(type, op, draw_end) \
{ \
int length; \
int pitch = (dst->pitch / dst->format->BytesPerPixel); \
type *pixel; \
if (y1 <= y2) { \
pixel = (type *)dst->pixels + y1 * pitch + x1; \
if (x1 <= x2) { \
++pitch; \
} else { \
--pitch; \
} \
length = (y2-y1); \
} else { \
pixel = (type *)dst->pixels + y2 * pitch + x2; \
if (x2 <= x1) { \
++pitch; \
} else { \
--pitch; \
} \
if (!draw_end) { \
pixel += pitch; \
} \
length = (y1-y2); \
} \
if (draw_end) { \
++length; \
} \
while (length--) { \
op; \
pixel += pitch; \
} \
}
/* Bresenham's line algorithm */
#define BLINE(x1, y1, x2, y2, op, draw_end) \
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int i, deltax, deltay, numpixels; \
int d, dinc1, dinc2; \
int x, xinc1, xinc2; \
int y, yinc1, yinc2; \
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deltax = ABS(x2 - x1); \
deltay = ABS(y2 - y1); \
\
if (deltax >= deltay) { \
numpixels = deltax + 1; \
d = (2 * deltay) - deltax; \
dinc1 = deltay * 2; \
dinc2 = (deltay - deltax) * 2; \
xinc1 = 1; \
xinc2 = 1; \
yinc1 = 0; \
yinc2 = 1; \
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} else { \
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numpixels = deltay + 1; \
d = (2 * deltax) - deltay; \
dinc1 = deltax * 2; \
dinc2 = (deltax - deltay) * 2; \
xinc1 = 0; \
xinc2 = 1; \
yinc1 = 1; \
yinc2 = 1; \
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\
if (x1 > x2) { \
xinc1 = -xinc1; \
xinc2 = -xinc2; \
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if (y1 > y2) { \
yinc1 = -yinc1; \
yinc2 = -yinc2; \
} \
\
x = x1; \
y = y1; \
\
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if (!draw_end) { \
--numpixels; \
} \
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for (i = 0; i < numpixels; ++i) { \
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op(x, y); \
if (d < 0) { \
d += dinc1; \
x += xinc1; \
y += yinc1; \
} else { \
d += dinc2; \
x += xinc2; \
y += yinc2; \
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} \
} \
}
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/* Xiaolin Wu's line algorithm, based on Michael Abrash's implementation */
#define WULINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end) \
{ \
Uint16 ErrorAdj, ErrorAcc; \
Uint16 ErrorAccTemp, Weighting; \
int DeltaX, DeltaY, Temp, XDir; \
unsigned r, g, b, a, inva; \
\
/* Draw the initial pixel, which is always exactly intersected by \
the line and so needs no weighting */ \
opaque_op(x1, y1); \
\
/* Draw the final pixel, which is always exactly intersected by the line \
and so needs no weighting */ \
if (draw_end) { \
opaque_op(x2, y2); \
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\
/* Make sure the line runs top to bottom */ \
if (y1 > y2) { \
Temp = y1; y1 = y2; y2 = Temp; \
Temp = x1; x1 = x2; x2 = Temp; \
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DeltaY = y2 - y1; \
\
if ((DeltaX = x2 - x1) >= 0) { \
XDir = 1; \
} else { \
XDir = -1; \
DeltaX = -DeltaX; /* make DeltaX positive */ \
} \
\
/* line is not horizontal, diagonal, or vertical */ \
ErrorAcc = 0; /* initialize the line error accumulator to 0 */ \
\
/* Is this an X-major or Y-major line? */ \
if (DeltaY > DeltaX) { \
/* Y-major line; calculate 16-bit fixed-point fractional part of a \
pixel that X advances each time Y advances 1 pixel, truncating the \
result so that we won't overrun the endpoint along the X axis */ \
ErrorAdj = ((unsigned long) DeltaX << 16) / (unsigned long) DeltaY; \
/* Draw all pixels other than the first and last */ \
while (--DeltaY) { \
ErrorAccTemp = ErrorAcc; /* remember currrent accumulated error */ \
ErrorAcc += ErrorAdj; /* calculate error for next pixel */ \
if (ErrorAcc <= ErrorAccTemp) { \
/* The error accumulator turned over, so advance the X coord */ \
x1 += XDir; \
} \
y1++; /* Y-major, so always advance Y */ \
/* The IntensityBits most significant bits of ErrorAcc give us the \
intensity weighting for this pixel, and the complement of the \
weighting for the paired pixel */ \
Weighting = ErrorAcc >> 8; \
{ \
a = DRAW_MUL(_a, (Weighting ^ 255)); \
r = DRAW_MUL(_r, a); \
g = DRAW_MUL(_g, a); \
b = DRAW_MUL(_b, a); \
inva = (a ^ 0xFF); \
blend_op(x1, y1); \
} \
{ \
a = DRAW_MUL(_a, Weighting); \
r = DRAW_MUL(_r, a); \
g = DRAW_MUL(_g, a); \
b = DRAW_MUL(_b, a); \
inva = (a ^ 0xFF); \
blend_op(x1 + XDir, y1); \
} \
} \
} else { \
/* X-major line; calculate 16-bit fixed-point fractional part of a \
pixel that Y advances each time X advances 1 pixel, truncating the \
result to avoid overrunning the endpoint along the X axis */ \
ErrorAdj = ((unsigned long) DeltaY << 16) / (unsigned long) DeltaX; \
/* Draw all pixels other than the first and last */ \
while (--DeltaX) { \
ErrorAccTemp = ErrorAcc; /* remember currrent accumulated error */ \
ErrorAcc += ErrorAdj; /* calculate error for next pixel */ \
if (ErrorAcc <= ErrorAccTemp) { \
/* The error accumulator turned over, so advance the Y coord */ \
y1++; \
} \
x1 += XDir; /* X-major, so always advance X */ \
/* The IntensityBits most significant bits of ErrorAcc give us the \
intensity weighting for this pixel, and the complement of the \
weighting for the paired pixel */ \
Weighting = ErrorAcc >> 8; \
{ \
a = DRAW_MUL(_a, (Weighting ^ 255)); \
r = DRAW_MUL(_r, a); \
g = DRAW_MUL(_g, a); \
b = DRAW_MUL(_b, a); \
inva = (a ^ 0xFF); \
blend_op(x1, y1); \
} \
{ \
a = DRAW_MUL(_a, Weighting); \
r = DRAW_MUL(_r, a); \
g = DRAW_MUL(_g, a); \
b = DRAW_MUL(_b, a); \
inva = (a ^ 0xFF); \
blend_op(x1, y1 + 1); \
} \
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} \
} \
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}
#ifdef AA_LINES
#define AALINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end) \
WULINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end)
#else
#define AALINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end) \
BLINE(x1, y1, x2, y2, opaque_op, draw_end)
#endif
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/*
* Define fill rect macro
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#define FILLRECT(type, op) \
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int width = rect->w; \
int height = rect->h; \
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int pitch = (dst->pitch / dst->format->BytesPerPixel); \
int skip = pitch - width; \
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type *pixel = (type *)dst->pixels + rect->y * pitch + rect->x; \
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while (height--) { \
{ int n = (width+3)/4; \
switch (width & 3) { \
case 0: do { op; pixel++; \
case 3: op; pixel++; \
case 2: op; pixel++; \
case 1: op; pixel++; \
} while ( --n > 0 ); \
} \
} \
pixel += skip; \
} \
} while (0)
/* vi: set ts=4 sw=4 expandtab: */