Skip to content
This repository has been archived by the owner on Feb 11, 2021. It is now read-only.

Commit

Permalink
Share code between fill and line drawing
Browse files Browse the repository at this point in the history 
Added general RGB surface format fallbacks to drawing code
Fixed issues with destination surface alpha channel
  • Loading branch information
@slouken
slouken committed Dec 21, 2008
1 parent ab0e777 commit 2d2977c
Show file tree
Hide file tree
Showing 5 changed files with 677 additions and 336 deletions.
328 changes: 171 additions & 157 deletions src/video/SDL_blendline.c
View file
Expand Up @@ -21,198 +21,212 @@
*/
#include "SDL_config.h"

#include "SDL_video.h"
#include "SDL_blit.h"

#define ABS(_x) ((_x) < 0 ? -(_x) : (_x))

#define SWAP(_x, _y) do { int tmp; tmp = _x; _x = _y; _y = tmp; } while (0)

#define BRESENHAM(x0, y0, x1, y1, op) \
{ \
int deltax, deltay, steep, error, xstep, ystep, x, y; \
\
deltax = ABS(x1 - x0); \
deltay = ABS(y1 - y0); \
steep = (deltay > deltax); \
if (steep) { \
SWAP(x0, y0); \
SWAP(x1, y1); \
SWAP(deltax, deltay); \
} \
error = (x1 - x0) / 2; \
y = y0; \
if (x0 > x1) { \
xstep = -1; \
} else { \
xstep = 1; \
} \
if (y0 < y1) { \
ystep = 1; \
} else { \
ystep = -1; \
} \
if (!steep) { \
for (x = x0; x != x1; x += xstep) { \
op(x, y); \
error -= deltay; \
if (error < 0) { \
y += ystep; \
error += deltax; \
} \
} \
} else { \
for (x = x0; x != x1; x += xstep) { \
op(y, x); \
error -= deltay; \
if (error < 0) { \
y += ystep; \
error += deltax; \
} \
} \
} \
}
#include "SDL_draw.h"

#define MUL(_a, _b) (((Uint16)(_a)*(Uint16)(_b))/255)
#define SHIFTAND(_v, _s, _a) (((_v)>>(_s)) & _a)

#define SETPIXEL_MASK(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
do { \
type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
if (a) { \
*pixel = (r<<rshift) | (g<<gshift) | (b<<bshift); \
} \
} while (0)

#define SETPIXEL_BLEND(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
do { \
type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
Uint8 sr = MUL(inva, SHIFTAND(*pixel, rshift, rmask)) + (Uint16) r; \
Uint8 sg = MUL(inva, SHIFTAND(*pixel, gshift, gmask)) + (Uint16) g; \
Uint8 sb = MUL(inva, SHIFTAND(*pixel, bshift, bmask)) + (Uint16) b; \
*pixel = (sr<<rshift) | (sg<<gshift) | (sb<<bshift); \
} while (0)

#define SETPIXEL_ADD(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
do { \
type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
Uint16 sr = SHIFTAND(*pixel, rshift, rmask) + (Uint16) r; \
Uint16 sg = SHIFTAND(*pixel, gshift, gmask) + (Uint16) g; \
Uint16 sb = SHIFTAND(*pixel, bshift, bmask) + (Uint16) b; \
if (sr>rmask) sr = rmask; \
if (sg>gmask) sg = gmask; \
if (sb>bmask) sb = bmask; \
*pixel = (sr<<rshift) | (sg<<gshift) | (sb<<bshift); \
} while (0)

#define SETPIXEL_MOD(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
do { \
type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
Uint8 sr = MUL(SHIFTAND(*pixel, rshift, rmask), r); \
Uint8 sg = MUL(SHIFTAND(*pixel, gshift, gmask), g); \
Uint8 sb = MUL(SHIFTAND(*pixel, bshift, bmask), b); \
*pixel = (sr<<rshift) | (sg<<gshift) | (sb<<bshift); \
} while (0)


#define SETPIXEL15_MASK(x, y) SETPIXEL_MASK(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
#define SETPIXEL15_BLEND(x, y) SETPIXEL_BLEND(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
#define SETPIXEL15_ADD(x, y) SETPIXEL_ADD(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
#define SETPIXEL15_MOD(x, y) SETPIXEL_MOD(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);

#define SETPIXEL16_MASK(x, y) SETPIXEL_MASK(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
#define SETPIXEL16_BLEND(x, y) SETPIXEL_BLEND(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
#define SETPIXEL16_ADD(x, y) SETPIXEL_ADD(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
#define SETPIXEL16_MOD(x, y) SETPIXEL_MOD(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);

#define SETPIXEL32_MASK(x, y) SETPIXEL_MASK(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
#define SETPIXEL32_BLEND(x, y) SETPIXEL_BLEND(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
#define SETPIXEL32_ADD(x, y) SETPIXEL_ADD(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
#define SETPIXEL32_MOD(x, y) SETPIXEL_MOD(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
static int
SDL_BlendLine_RGB555(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
unsigned inva = 0xff - a;

int
SDL_BlendLine(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_BLEND_RGB555);
break;
case SDL_BLENDMODE_ADD:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_ADD_RGB555);
break;
case SDL_BLENDMODE_MOD:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_MOD_RGB555);
break;
default:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_RGB555);
break;
}
return 0;
}

static int
SDL_BlendLine_RGB565(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
Uint8 inva = 0xff - a;
/* This function doesn't work on surfaces < 8 bpp */
if (dst->format->BitsPerPixel < 8) {
SDL_SetError("SDL_BlendLine(): Unsupported surface format");
return (-1);
unsigned inva = 0xff - a;

switch (blendMode) {
case SDL_BLENDMODE_BLEND:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_BLEND_RGB565);
break;
case SDL_BLENDMODE_ADD:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_ADD_RGB565);
break;
case SDL_BLENDMODE_MOD:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_MOD_RGB565);
break;
default:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_RGB565);
break;
}
return 0;
}

/* Perform clipping */
/* FIXME
if (!SDL_IntersectRect(dstrect, &dst->clip_rect, dstrect)) {
return (0);
}
*/
static int
SDL_BlendLine_RGB888(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
unsigned inva = 0xff - a;

if ((blendMode == SDL_BLENDMODE_BLEND)
|| (blendMode == SDL_BLENDMODE_ADD)) {
r = MUL(r, a);
g = MUL(g, a);
b = MUL(b, a);
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_BLEND_RGB888);
break;
case SDL_BLENDMODE_ADD:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_ADD_RGB888);
break;
case SDL_BLENDMODE_MOD:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_MOD_RGB888);
break;
default:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY_RGB888);
break;
}
switch (dst->format->BitsPerPixel) {
case 15:
return 0;
}

static int
SDL_BlendLine_RGB(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
SDL_PixelFormat *fmt = dst->format;
unsigned inva = 0xff - a;

switch (fmt->BytesPerPixel) {
case 2:
switch (blendMode) {
case SDL_BLENDMODE_MASK:
BRESENHAM(x1, y1, x2, y2, SETPIXEL15_MASK);
break;
case SDL_BLENDMODE_BLEND:
BRESENHAM(x1, y1, x2, y2, SETPIXEL15_BLEND);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY2_BLEND_RGB);
break;
case SDL_BLENDMODE_ADD:
BRESENHAM(x1, y1, x2, y2, SETPIXEL15_ADD);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY2_ADD_RGB);
break;
case SDL_BLENDMODE_MOD:
BRESENHAM(x1, y1, x2, y2, SETPIXEL15_MOD);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY2_MOD_RGB);
break;
default:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY2_RGB);
break;
}
break;
case 16:
return 0;
case 4:
switch (blendMode) {
case SDL_BLENDMODE_MASK:
BRESENHAM(x1, y1, x2, y2, SETPIXEL16_MASK);
break;
case SDL_BLENDMODE_BLEND:
BRESENHAM(x1, y1, x2, y2, SETPIXEL16_BLEND);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_BLEND_RGB);
break;
case SDL_BLENDMODE_ADD:
BRESENHAM(x1, y1, x2, y2, SETPIXEL16_ADD);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_ADD_RGB);
break;
case SDL_BLENDMODE_MOD:
BRESENHAM(x1, y1, x2, y2, SETPIXEL16_MOD);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_MOD_RGB);
break;
default:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_RGB);
break;
}
break;
case 24:
case 32:
if (dst->format->BytesPerPixel != 4) {
SDL_Unsupported();
return -1;
}
return 0;
default:
SDL_Unsupported();
return -1;
}
}

static int
SDL_BlendLine_RGBA(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
SDL_PixelFormat *fmt = dst->format;
unsigned inva = 0xff - a;

switch (fmt->BytesPerPixel) {
case 4:
switch (blendMode) {
case SDL_BLENDMODE_MASK:
BRESENHAM(x1, y1, x2, y2, SETPIXEL32_MASK);
break;
case SDL_BLENDMODE_BLEND:
BRESENHAM(x1, y1, x2, y2, SETPIXEL32_BLEND);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_BLEND_RGBA);
break;
case SDL_BLENDMODE_ADD:
BRESENHAM(x1, y1, x2, y2, SETPIXEL32_ADD);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_ADD_RGBA);
break;
case SDL_BLENDMODE_MOD:
BRESENHAM(x1, y1, x2, y2, SETPIXEL32_MOD);
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_MOD_RGBA);
break;
default:
BRESENHAM(x1, y1, x2, y2, DRAW_SETPIXELXY4_RGBA);
break;
}
break;
return 0;
default:
SDL_Unsupported();
return -1;
}
return 0;
}

int
SDL_BlendLine(SDL_Surface * dst, int x1, int y1, int x2, int y2,
int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
SDL_PixelFormat *fmt = dst->format;

/* This function doesn't work on surfaces < 8 bpp */
if (dst->format->BitsPerPixel < 8) {
SDL_SetError("SDL_BlendLine(): Unsupported surface format");
return (-1);
}

/* Perform clipping */
/* FIXME
if (!SDL_IntersectRect(dstrect, &dst->clip_rect, dstrect)) {
return (0);
}
*/

if ((blendMode == SDL_BLENDMODE_BLEND)
|| (blendMode == SDL_BLENDMODE_ADD)) {
r = DRAW_MUL(r, a);
g = DRAW_MUL(g, a);
b = DRAW_MUL(b, a);
}

switch (fmt->BitsPerPixel) {
case 15:
switch (fmt->Rmask) {
case 0x7C00:
return SDL_BlendLine_RGB555(dst, x1, y1, x2, y2, blendMode, r, g,
b, a);
}
break;
case 16:
switch (fmt->Rmask) {
case 0xF800:
return SDL_BlendLine_RGB565(dst, x1, y1, x2, y2, blendMode, r, g,
b, a);
}
break;
case 32:
switch (fmt->Rmask) {
case 0x00FF0000:
if (!fmt->Amask) {
return SDL_BlendLine_RGB888(dst, x1, y1, x2, y2, blendMode, r,
g, b, a);
}
break;
}
default:
break;
}

if (!fmt->Amask) {
return SDL_BlendLine_RGB(dst, x1, y1, x2, y2, blendMode, r, g, b, a);
} else {
return SDL_BlendLine_RGBA(dst, x1, y1, x2, y2, blendMode, r, g, b, a);
}
}

/* vi: set ts=4 sw=4 expandtab: */

0 comments on commit 2d2977c

Please sign in to comment.