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SDL_blendpoint.c
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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"
#include "SDL_draw.h"
static int
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SDL_BlendPoint_RGB555(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
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Uint8 g, Uint8 b, Uint8 a)
{
unsigned inva = 0xff - a;
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
DRAW_SETPIXELXY_BLEND_RGB555(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY_ADD_RGB555(x, y);
break;
default:
DRAW_SETPIXELXY_RGB555(x, y);
break;
}
return 0;
}
static int
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SDL_BlendPoint_RGB565(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
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Uint8 g, Uint8 b, Uint8 a)
{
unsigned inva = 0xff - a;
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
DRAW_SETPIXELXY_BLEND_RGB565(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY_ADD_RGB565(x, y);
break;
default:
DRAW_SETPIXELXY_RGB565(x, y);
break;
}
return 0;
}
static int
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SDL_BlendPoint_RGB888(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
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Uint8 g, Uint8 b, Uint8 a)
{
unsigned inva = 0xff - a;
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
DRAW_SETPIXELXY_BLEND_RGB888(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY_ADD_RGB888(x, y);
break;
default:
DRAW_SETPIXELXY_RGB888(x, y);
break;
}
return 0;
}
static int
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SDL_BlendPoint_ARGB8888(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode,
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Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
unsigned inva = 0xff - a;
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
DRAW_SETPIXELXY_BLEND_ARGB8888(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY_ADD_ARGB8888(x, y);
break;
default:
DRAW_SETPIXELXY_ARGB8888(x, y);
break;
}
return 0;
}
static int
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SDL_BlendPoint_RGB(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
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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_BLEND:
DRAW_SETPIXELXY2_BLEND_RGB(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY2_ADD_RGB(x, y);
break;
default:
DRAW_SETPIXELXY2_RGB(x, y);
break;
}
return 0;
case 4:
switch (blendMode) {
case SDL_BLENDMODE_BLEND:
DRAW_SETPIXELXY4_BLEND_RGB(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY4_ADD_RGB(x, y);
break;
default:
DRAW_SETPIXELXY4_RGB(x, y);
break;
}
return 0;
default:
SDL_Unsupported();
return -1;
}
}
static int
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SDL_BlendPoint_RGBA(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
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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_BLEND:
DRAW_SETPIXELXY4_BLEND_RGBA(x, y);
break;
case SDL_BLENDMODE_ADD:
DRAW_SETPIXELXY4_ADD_RGBA(x, y);
break;
default:
DRAW_SETPIXELXY4_RGBA(x, y);
break;
}
return 0;
default:
SDL_Unsupported();
return -1;
}
}
int
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SDL_BlendPoint(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
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Uint8 g, Uint8 b, Uint8 a)
{
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if (!dst) {
SDL_SetError("Passed NULL destination surface");
return -1;
}
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/* This function doesn't work on surfaces < 8 bpp */
if (dst->format->BitsPerPixel < 8) {
SDL_SetError("SDL_BlendPoint(): Unsupported surface format");
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}
/* Perform clipping */
if (x < dst->clip_rect.x || y < dst->clip_rect.y ||
x >= (dst->clip_rect.x + dst->clip_rect.w) ||
y >= (dst->clip_rect.y + dst->clip_rect.h)) {
return 0;
}
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if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
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r = DRAW_MUL(r, a);
g = DRAW_MUL(g, a);
b = DRAW_MUL(b, a);
}
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switch (dst->format->BitsPerPixel) {
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case 15:
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switch (dst->format->Rmask) {
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case 0x7C00:
return SDL_BlendPoint_RGB555(dst, x, y, blendMode, r, g, b, a);
}
break;
case 16:
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switch (dst->format->Rmask) {
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case 0xF800:
return SDL_BlendPoint_RGB565(dst, x, y, blendMode, r, g, b, a);
}
break;
case 32:
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switch (dst->format->Rmask) {
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case 0x00FF0000:
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if (!dst->format->Amask) {
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return SDL_BlendPoint_RGB888(dst, x, y, blendMode, r, g, b,
a);
} else {
return SDL_BlendPoint_ARGB8888(dst, x, y, blendMode, r, g, b,
a);
}
break;
}
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default:
break;
}
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if (!dst->format->Amask) {
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return SDL_BlendPoint_RGB(dst, x, y, blendMode, r, g, b, a);
} else {
return SDL_BlendPoint_RGBA(dst, x, y, blendMode, r, g, b, a);
}
}
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int
SDL_BlendPoints(SDL_Surface * dst, const SDL_Point * points, int count,
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SDL_BlendMode blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
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{
int minx, miny;
int maxx, maxy;
int i;
int x, y;
int (*func)(SDL_Surface * dst, int x, int y,
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SDL_BlendMode blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a) = NULL;
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int status = 0;
if (!dst) {
SDL_SetError("Passed NULL destination surface");
return -1;
}
/* This function doesn't work on surfaces < 8 bpp */
if (dst->format->BitsPerPixel < 8) {
SDL_SetError("SDL_BlendPoints(): Unsupported surface format");
return (-1);
}
if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
r = DRAW_MUL(r, a);
g = DRAW_MUL(g, a);
b = DRAW_MUL(b, a);
}
/* FIXME: Does this function pointer slow things down significantly? */
switch (dst->format->BitsPerPixel) {
case 15:
switch (dst->format->Rmask) {
case 0x7C00:
func = SDL_BlendPoint_RGB555;
break;
}
break;
case 16:
switch (dst->format->Rmask) {
case 0xF800:
func = SDL_BlendPoint_RGB565;
break;
}
break;
case 32:
switch (dst->format->Rmask) {
case 0x00FF0000:
if (!dst->format->Amask) {
func = SDL_BlendPoint_RGB888;
} else {
func = SDL_BlendPoint_ARGB8888;
}
break;
}
break;
default:
break;
}
if (!func) {
if (!dst->format->Amask) {
func = SDL_BlendPoint_RGB;
} else {
func = SDL_BlendPoint_RGBA;
}
}
minx = dst->clip_rect.x;
maxx = dst->clip_rect.x + dst->clip_rect.w - 1;
miny = dst->clip_rect.y;
maxy = dst->clip_rect.y + dst->clip_rect.h - 1;
for (i = 0; i < count; ++i) {
x = points[i].x;
y = points[i].y;
if (x < minx || x > maxx || y < miny || y > maxy) {
continue;
}
status = func(dst, x, y, blendMode, r, g, b, a);
}
return status;
}
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/* vi: set ts=4 sw=4 expandtab: */