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SDL_gfxPrimitives.c
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SDL_gfxPrimitives.c
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/*
SDL_gfxPrimitives.c: graphics primitives for SDL surfaces
Copyright (C) 2001-2023 Andreas Schiffler
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source
distribution.
Andreas Schiffler -- aschiffler at ferzkopp dot net
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include "SDL_gfxPrimitives.h"
#include "SDL_rotozoom.h"
#include "SDL_gfxPrimitives_font.h"
#include "SDL_gfxBlitFunc.h"
/* -===================- */
#define DEFAULT_ALPHA_PIXEL_ROUTINE
#undef EXPERIMENTAL_ALPHA_PIXEL_ROUTINE
#define ALPHA_PIXEL_ADDITIVE_BLEND
/* ---- Structures */
/*!
\brief The structure passed to the internal Bresenham iterator.
*/
typedef struct {
Sint16 x, y;
int dx, dy, s1, s2, swapdir, error;
Uint32 count;
} SDL_gfxBresenhamIterator;
/*!
\brief The structure passed to the internal Murphy iterator.
*/
typedef struct {
Uint32 color;
SDL_Surface *dst;
int u, v; /* delta x , delta y */
int ku, kt, kv, kd; /* loop constants */
int oct2;
int quad4;
Sint16 last1x, last1y, last2x, last2y, first1x, first1y, first2x, first2y, tempx, tempy;
} SDL_gfxMurphyIterator;
/* ----- Defines for pixel clipping tests */
#define clip_xmin(surface) surface->clip_rect.x
#define clip_xmax(surface) surface->clip_rect.x+surface->clip_rect.w-1
#define clip_ymin(surface) surface->clip_rect.y
#define clip_ymax(surface) surface->clip_rect.y+surface->clip_rect.h-1
/*!
\brief Internal pixel drawing - fast, no blending, no locking, clipping.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param color The color value of the pixel to draw.
\returns Returns 0 on success, -1 on failure.
*/
int fastPixelColorNolock(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color)
{
int bpp;
Uint8 *p;
/*
* Honor clipping setup at pixel level
*/
if ((x >= clip_xmin(dst)) && (x <= clip_xmax(dst)) && (y >= clip_ymin(dst)) && (y <= clip_ymax(dst))) {
/*
* Get destination format
*/
bpp = dst->format->BytesPerPixel;
p = (Uint8 *) dst->pixels + y * dst->pitch + x * bpp;
switch (bpp) {
case 1:
*p = color;
break;
case 2:
*(Uint16 *) p = color;
break;
case 3:
#if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
p[0] = (color >> 16) & 0xff;
p[1] = (color >> 8) & 0xff;
p[2] = color & 0xff;
#else
p[0] = color & 0xff;
p[1] = (color >> 8) & 0xff;
p[2] = (color >> 16) & 0xff;
#endif
break;
case 4:
*(Uint32 *) p = color;
break;
} /* switch */
}
return (0);
}
/*!
\brief Internal pixel drawing - fast, no blending, no locking, no clipping.
Function is faster but dangerous since no clipping check is done.
Code needs to make sure we stay in surface bounds before calling.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param color The color value of the pixel to draw.
\returns Returns 0 on success, -1 on failure.
*/
int fastPixelColorNolockNoclip(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color)
{
int bpp;
Uint8 *p;
/*
* Get destination format
*/
bpp = dst->format->BytesPerPixel;
p = (Uint8 *) dst->pixels + y * dst->pitch + x * bpp;
switch (bpp) {
case 1:
*p = color;
break;
case 2:
*(Uint16 *) p = color;
break;
case 3:
#if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
p[0] = (color >> 16) & 0xff;
p[1] = (color >> 8) & 0xff;
p[2] = color & 0xff;
#else
p[0] = color & 0xff;
p[1] = (color >> 8) & 0xff;
p[2] = (color >> 16) & 0xff;
#endif
break;
case 4:
*(Uint32 *) p = color;
break;
} /* switch */
return (0);
}
/*!
\brief Internal pixel drawing - fast, no blending, locking, clipping.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param color The color value of the pixel to draw.
\returns Returns 0 on success, -1 on failure.
*/
int fastPixelColor(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color)
{
int result;
/*
* Lock the surface
*/
if (SDL_MUSTLOCK(dst)) {
if (SDL_LockSurface(dst) < 0) {
return (-1);
}
}
result = fastPixelColorNolock(dst, x, y, color);
/*
* Unlock surface
*/
if (SDL_MUSTLOCK(dst)) {
SDL_UnlockSurface(dst);
}
return (result);
}
/*!
\brief Internal pixel drawing - fast, no blending, locking, RGB input.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param r The red value of the pixel to draw.
\param g The green value of the pixel to draw.
\param b The blue value of the pixel to draw.
\param a The alpha value of the pixel to draw.
\returns Returns 0 on success, -1 on failure.
*/
int fastPixelRGBA(SDL_Surface * dst, Sint16 x, Sint16 y, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
Uint32 color;
/*
* Setup color
*/
color = SDL_MapRGBA(dst->format, r, g, b, a);
/*
* Draw
*/
return (fastPixelColor(dst, x, y, color));
}
/*!
\brief Internal pixel drawing - fast, no blending, no locking RGB input.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param r The red value of the pixel to draw.
\param g The green value of the pixel to draw.
\param b The blue value of the pixel to draw.
\param a The alpha value of the pixel to draw.
\returns Returns 0 on success, -1 on failure.
*/
int fastPixelRGBANolock(SDL_Surface * dst, Sint16 x, Sint16 y, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
Uint32 color;
/*
* Setup color
*/
color = SDL_MapRGBA(dst->format, r, g, b, a);
/*
* Draw
*/
return (fastPixelColorNolock(dst, x, y, color));
}
/*!
\brief Internal pixel drawing function with alpha blending where input color in in destination format.
Contains two alternative 32 bit alpha blending routines which can be enabled at the source
level with the defines DEFAULT_ALPHA_PIXEL_ROUTINE or EXPERIMENTAL_ALPHA_PIXEL_ROUTINE.
Only the bits up to the surface depth are significant in the color value.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param color The color value of the pixel to draw.
\param alpha The blend factor to apply while drawing.
\returns Returns 0 on success, -1 on failure.
*/
int _putPixelAlpha(SDL_Surface *dst, Sint16 x, Sint16 y, Uint32 color, Uint8 alpha)
{
SDL_PixelFormat *format;
Uint32 Rmask, Gmask, Bmask, Amask;
Uint32 Rshift, Gshift, Bshift, Ashift;
Uint32 sR, sG, sB;
Uint32 dR, dG, dB, dA;
if (dst == NULL)
{
return (-1);
}
if (x >= clip_xmin(dst) && x <= clip_xmax(dst) &&
y >= clip_ymin(dst) && y <= clip_ymax(dst))
{
format = dst->format;
switch (format->BytesPerPixel) {
case 1:
{ /* Assuming 8-bpp */
Uint8 *pixel = (Uint8 *) dst->pixels + y * dst->pitch + x;
if (alpha == 255) {
*pixel = color;
} else {
Uint8 R, G, B;
SDL_Palette *palette = format->palette;
SDL_Color *colors = palette->colors;
SDL_Color dColor = colors[*pixel];
SDL_Color sColor = colors[color];
dR = dColor.r;
dG = dColor.g;
dB = dColor.b;
sR = sColor.r;
sG = sColor.g;
sB = sColor.b;
R = dR + ((sR - dR) * alpha >> 8);
G = dG + ((sG - dG) * alpha >> 8);
B = dB + ((sB - dB) * alpha >> 8);
*pixel = SDL_MapRGB(format, R, G, B);
}
}
break;
case 2:
{ /* Probably 15-bpp or 16-bpp */
Uint16 *pixel = (Uint16 *) dst->pixels + y * dst->pitch / 2 + x;
if (alpha == 255) {
*pixel = color;
} else {
Uint16 R, G, B, A;
Uint16 dc = *pixel;
Rmask = format->Rmask;
Gmask = format->Gmask;
Bmask = format->Bmask;
Amask = format->Amask;
dR = (dc & Rmask);
dG = (dc & Gmask);
dB = (dc & Bmask);
R = (dR + (((color & Rmask) - dR) * alpha >> 8)) & Rmask;
G = (dG + (((color & Gmask) - dG) * alpha >> 8)) & Gmask;
B = (dB + (((color & Bmask) - dB) * alpha >> 8)) & Bmask;
*pixel = R | G | B;
if (Amask!=0) {
dA = (dc & Amask);
A = (dA + (((color & Amask) - dA) * alpha >> 8)) & Amask;
*pixel |= A;
}
}
}
break;
case 3:
{ /* Slow 24-bpp mode, usually not used */
Uint8 R, G, B;
Uint8 Rshift8, Gshift8, Bshift8;
Uint8 *pixel = (Uint8 *) dst->pixels + y * dst->pitch + x * 3;
Rshift = format->Rshift;
Gshift = format->Gshift;
Bshift = format->Bshift;
Rshift8 = Rshift >> 3;
Gshift8 = Gshift >> 3;
Bshift8 = Bshift >> 3;
sR = (color >> Rshift) & 0xFF;
sG = (color >> Gshift) & 0xFF;
sB = (color >> Bshift) & 0xFF;
if (alpha == 255) {
*(pixel + Rshift8) = sR;
*(pixel + Gshift8) = sG;
*(pixel + Bshift8) = sB;
} else {
dR = *((pixel) + Rshift8);
dG = *((pixel) + Gshift8);
dB = *((pixel) + Bshift8);
R = dR + ((sR - dR) * alpha >> 8);
G = dG + ((sG - dG) * alpha >> 8);
B = dB + ((sB - dB) * alpha >> 8);
*((pixel) + Rshift8) = R;
*((pixel) + Gshift8) = G;
*((pixel) + Bshift8) = B;
}
}
break;
#ifdef DEFAULT_ALPHA_PIXEL_ROUTINE
case 4:
{ /* Probably :-) 32-bpp */
Uint32 R, G, B, A;
Uint32 *pixel = (Uint32 *) dst->pixels + y * dst->pitch / 4 + x;
if (alpha == 255) {
*pixel = color;
} else {
Uint32 dc = *pixel;
Rmask = format->Rmask;
Gmask = format->Gmask;
Bmask = format->Bmask;
Amask = format->Amask;
Rshift = format->Rshift;
Gshift = format->Gshift;
Bshift = format->Bshift;
Ashift = format->Ashift;
dR = (dc & Rmask) >> Rshift;
dG = (dc & Gmask) >> Gshift;
dB = (dc & Bmask) >> Bshift;
R = ((dR + ((((color & Rmask) >> Rshift) - dR) * alpha >> 8)) << Rshift) & Rmask;
G = ((dG + ((((color & Gmask) >> Gshift) - dG) * alpha >> 8)) << Gshift) & Gmask;
B = ((dB + ((((color & Bmask) >> Bshift) - dB) * alpha >> 8)) << Bshift) & Bmask;
*pixel = R | G | B;
if (Amask!=0) {
dA = (dc & Amask) >> Ashift;
#ifdef ALPHA_PIXEL_ADDITIVE_BLEND
A = (dA | GFX_ALPHA_ADJUST_ARRAY[alpha & 255]) << Ashift; // make destination less transparent...
#else
A = ((dA + ((((color & Amask) >> Ashift) - dA) * alpha >> 8)) << Ashift) & Amask;
#endif
*pixel |= A;
}
}
}
break;
#endif
#ifdef EXPERIMENTAL_ALPHA_PIXEL_ROUTINE
case 4:{ /* Probably :-) 32-bpp */
if (alpha == 255) {
*((Uint32 *) dst->pixels + y * dst->pitch / 4 + x) = color;
} else {
Uint32 *pixel = (Uint32 *) dst->pixels + y * dst->pitch / 4 + x;
Uint32 dR, dG, dB, dA;
Uint32 dc = *pixel;
Uint32 surfaceAlpha, preMultR, preMultG, preMultB;
Uint32 aTmp;
Rmask = format->Rmask;
Gmask = format->Gmask;
Bmask = format->Bmask;
Amask = format->Amask;
dR = (color & Rmask);
dG = (color & Gmask);
dB = (color & Bmask);
dA = (color & Amask);
Rshift = format->Rshift;
Gshift = format->Gshift;
Bshift = format->Bshift;
Ashift = format->Ashift;
preMultR = (alpha * (dR >> Rshift));
preMultG = (alpha * (dG >> Gshift));
preMultB = (alpha * (dB >> Bshift));
surfaceAlpha = ((dc & Amask) >> Ashift);
aTmp = (255 - alpha);
if (A = 255 - ((aTmp * (255 - surfaceAlpha)) >> 8 )) {
aTmp *= surfaceAlpha;
R = (preMultR + ((aTmp * ((dc & Rmask) >> Rshift)) >> 8)) / A << Rshift & Rmask;
G = (preMultG + ((aTmp * ((dc & Gmask) >> Gshift)) >> 8)) / A << Gshift & Gmask;
B = (preMultB + ((aTmp * ((dc & Bmask) >> Bshift)) >> 8)) / A << Bshift & Bmask;
}
*pixel = R | G | B | (A << Ashift & Amask);
}
}
break;
#endif
}
}
return (0);
}
/*!
\brief Pixel draw with blending enabled if a<255.
\param dst The surface to draw on.
\param x X (horizontal) coordinate of the pixel.
\param y Y (vertical) coordinate of the pixel.
\param color The color value of the pixel to draw (0xRRGGBBAA).
\returns Returns 0 on success, -1 on failure.
*/
int pixelColor(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color)
{
Uint8 alpha;
Uint32 mcolor;
int result = 0;
/*
* Lock the surface
*/
if (SDL_MUSTLOCK(dst)) {
if (SDL_LockSurface(dst) < 0) {
return (-1);
}
}
/*
* Setup color
*/
alpha = color & 0x000000ff;
mcolor =
SDL_MapRGBA(dst->format, (color & 0xff000000) >> 24,
(color & 0x00ff0000) >> 16, (color & 0x0000ff00) >> 8, alpha);
/*
* Draw
*/
result = _putPixelAlpha(dst, x, y, mcolor, alpha);
/*
* Unlock the surface
*/
if (SDL_MUSTLOCK(dst)) {
SDL_UnlockSurface(dst);
}
return (result);
}
/*!
\brief Pixel draw with blending enabled if a<255 - no surface locking.
\param dst The surface to draw on.
\param x X (horizontal) coordinate of the pixel.
\param y Y (vertical) coordinate of the pixel.
\param color The color value of the pixel to draw (0xRRGGBBAA).
\returns Returns 0 on success, -1 on failure.
*/
int pixelColorNolock(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color)
{
Uint8 alpha;
Uint32 mcolor;
int result = 0;
/*
* Setup color
*/
alpha = color & 0x000000ff;
mcolor =
SDL_MapRGBA(dst->format, (color & 0xff000000) >> 24,
(color & 0x00ff0000) >> 16, (color & 0x0000ff00) >> 8, alpha);
/*
* Draw
*/
result = _putPixelAlpha(dst, x, y, mcolor, alpha);
return (result);
}
/*!
\brief Internal function to draw filled rectangle with alpha blending.
Assumes color is in destination format.
\param dst The surface to draw on.
\param x1 X coordinate of the first corner (upper left) of the rectangle.
\param y1 Y coordinate of the first corner (upper left) of the rectangle.
\param x2 X coordinate of the second corner (lower right) of the rectangle.
\param y2 Y coordinate of the second corner (lower right) of the rectangle.
\param color The color value of the rectangle to draw (0xRRGGBBAA).
\param alpha Alpha blending amount for pixels.
\returns Returns 0 on success, -1 on failure.
*/
int _filledRectAlpha(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color, Uint8 alpha)
{
SDL_PixelFormat *format;
Uint32 Rmask, Gmask, Bmask, Amask;
Uint32 Rshift, Gshift, Bshift, Ashift;
Uint32 sR, sG, sB, sA;
Uint32 dR, dG, dB, dA;
Sint16 x, y;
if (dst == NULL) {
return (-1);
}
format = dst->format;
switch (format->BytesPerPixel) {
case 1:
{ /* Assuming 8-bpp */
Uint8 *row, *pixel;
Uint8 R, G, B;
SDL_Color *colors = format->palette->colors;
SDL_Color dColor;
SDL_Color sColor = colors[color];
sR = sColor.r;
sG = sColor.g;
sB = sColor.b;
for (y = y1; y <= y2; y++) {
row = (Uint8 *) dst->pixels + y * dst->pitch;
for (x = x1; x <= x2; x++) {
if (alpha == 255) {
*(row + x) = color;
} else {
pixel = row + x;
dColor = colors[*pixel];
dR = dColor.r;
dG = dColor.g;
dB = dColor.b;
R = dR + ((sR - dR) * alpha >> 8);
G = dG + ((sG - dG) * alpha >> 8);
B = dB + ((sB - dB) * alpha >> 8);
*pixel = SDL_MapRGB(format, R, G, B);
}
}
}
}
break;
case 2:
{ /* Probably 15-bpp or 16-bpp */
Uint16 *row, *pixel;
Uint16 R, G, B, A;
Uint16 dc;
Rmask = format->Rmask;
Gmask = format->Gmask;
Bmask = format->Bmask;
Amask = format->Amask;
sR = (color & Rmask);
sG = (color & Gmask);
sB = (color & Bmask);
sA = (color & Amask);
for (y = y1; y <= y2; y++) {
row = (Uint16 *) dst->pixels + y * dst->pitch / 2;
for (x = x1; x <= x2; x++) {
if (alpha == 255) {
*(row + x) = color;
} else {
pixel = row + x;
dc = *pixel;
dR = (dc & Rmask);
dG = (dc & Gmask);
dB = (dc & Bmask);
R = (dR + ((sR - dR) * alpha >> 8)) & Rmask;
G = (dG + ((sG - dG) * alpha >> 8)) & Gmask;
B = (dB + ((sB - dB) * alpha >> 8)) & Bmask;
*pixel = R | G | B;
if (Amask!=0) {
dA = (dc & Amask);
A = (dA + ((sA - dA) * alpha >> 8)) & Amask;
*pixel |= A;
}
}
}
}
}
break;
case 3:
{ /* Slow 24-bpp mode, usually not used */
Uint8 *row, *pixel;
Uint8 R, G, B;
Uint8 Rshift8, Gshift8, Bshift8;
Rshift = format->Rshift;
Gshift = format->Gshift;
Bshift = format->Bshift;
Rshift8 = Rshift >> 3;
Gshift8 = Gshift >> 3;
Bshift8 = Bshift >> 3;
sR = (color >> Rshift) & 0xff;
sG = (color >> Gshift) & 0xff;
sB = (color >> Bshift) & 0xff;
for (y = y1; y <= y2; y++) {
row = (Uint8 *) dst->pixels + y * dst->pitch;
for (x = x1; x <= x2; x++) {
pixel = row + x * 3;
if (alpha == 255) {
*(pixel + Rshift8) = sR;
*(pixel + Gshift8) = sG;
*(pixel + Bshift8) = sB;
} else {
dR = *((pixel) + Rshift8);
dG = *((pixel) + Gshift8);
dB = *((pixel) + Bshift8);
R = dR + ((sR - dR) * alpha >> 8);
G = dG + ((sG - dG) * alpha >> 8);
B = dB + ((sB - dB) * alpha >> 8);
*((pixel) + Rshift8) = R;
*((pixel) + Gshift8) = G;
*((pixel) + Bshift8) = B;
}
}
}
}
break;
#ifdef DEFAULT_ALPHA_PIXEL_ROUTINE
case 4:
{ /* Probably :-) 32-bpp */
Uint32 *row, *pixel;
Uint32 R, G, B, A;
Uint32 dc;
Rmask = format->Rmask;
Gmask = format->Gmask;
Bmask = format->Bmask;
Amask = format->Amask;
Rshift = format->Rshift;
Gshift = format->Gshift;
Bshift = format->Bshift;
Ashift = format->Ashift;
sR = (color & Rmask) >> Rshift;
sG = (color & Gmask) >> Gshift;
sB = (color & Bmask) >> Bshift;
sA = (color & Amask) >> Ashift;
for (y = y1; y <= y2; y++) {
row = (Uint32 *) dst->pixels + y * dst->pitch / 4;
for (x = x1; x <= x2; x++) {
if (alpha == 255) {
*(row + x) = color;
} else {
pixel = row + x;
dc = *pixel;
dR = (dc & Rmask) >> Rshift;
dG = (dc & Gmask) >> Gshift;
dB = (dc & Bmask) >> Bshift;
R = ((dR + ((sR - dR) * alpha >> 8)) << Rshift) & Rmask;
G = ((dG + ((sG - dG) * alpha >> 8)) << Gshift) & Gmask;
B = ((dB + ((sB - dB) * alpha >> 8)) << Bshift) & Bmask;
*pixel = R | G | B;
if (Amask!=0) {
dA = (dc & Amask) >> Ashift;
#ifdef ALPHA_PIXEL_ADDITIVE_BLEND
A = (dA | GFX_ALPHA_ADJUST_ARRAY[sA & 255]) << Ashift; // make destination less transparent...
#else
A = ((dA + ((sA - dA) * alpha >> 8)) << Ashift) & Amask;
#endif
*pixel |= A;
}
}
}
}
}
break;
#endif
#ifdef EXPERIMENTAL_ALPHA_PIXEL_ROUTINE
case 4:{ /* Probably :-) 32-bpp */
Uint32 *row, *pixel;
Uint32 dR, dG, dB, dA;
Uint32 dc;
Uint32 surfaceAlpha, preMultR, preMultG, preMultB;
Uint32 aTmp;
Rmask = format->Rmask;
Gmask = format->Gmask;
Bmask = format->Bmask;
Amask = format->Amask;
dR = (color & Rmask);
dG = (color & Gmask);
dB = (color & Bmask);
dA = (color & Amask);
Rshift = format->Rshift;
Gshift = format->Gshift;
Bshift = format->Bshift;
Ashift = format->Ashift;
preMultR = (alpha * (dR >> Rshift));
preMultG = (alpha * (dG >> Gshift));
preMultB = (alpha * (dB >> Bshift));
for (y = y1; y <= y2; y++) {
row = (Uint32 *) dst->pixels + y * dst->pitch / 4;
for (x = x1; x <= x2; x++) {
if (alpha == 255) {
*(row + x) = color;
} else {
pixel = row + x;
dc = *pixel;
surfaceAlpha = ((dc & Amask) >> Ashift);
aTmp = (255 - alpha);
if (A = 255 - ((aTmp * (255 - surfaceAlpha)) >> 8 )) {
aTmp *= surfaceAlpha;
R = (preMultR + ((aTmp * ((dc & Rmask) >> Rshift)) >> 8)) / A << Rshift & Rmask;
G = (preMultG + ((aTmp * ((dc & Gmask) >> Gshift)) >> 8)) / A << Gshift & Gmask;
B = (preMultB + ((aTmp * ((dc & Bmask) >> Bshift)) >> 8)) / A << Bshift & Bmask;
}
*pixel = R | G | B | (A << Ashift & Amask);
}
}
}
}
break;
#endif
}
return (0);
}
/*!
\brief Draw filled rectangle of RGBA color with alpha blending.
\param dst The surface to draw on.
\param x1 X coordinate of the first corner (upper left) of the rectangle.
\param y1 Y coordinate of the first corner (upper left) of the rectangle.
\param x2 X coordinate of the second corner (lower right) of the rectangle.
\param y2 Y coordinate of the second corner (lower right) of the rectangle.
\param color The color value of the rectangle to draw (0xRRGGBBAA).
\returns Returns 0 on success, -1 on failure.
*/
int filledRectAlpha(SDL_Surface * dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color)
{
Uint8 alpha;
Uint32 mcolor;
int result = 0;
/*
* Lock the surface
*/
if (SDL_MUSTLOCK(dst)) {
if (SDL_LockSurface(dst) < 0) {
return (-1);
}
}
/*
* Setup color
*/
alpha = color & 0x000000ff;
mcolor =
SDL_MapRGBA(dst->format, (color & 0xff000000) >> 24,
(color & 0x00ff0000) >> 16, (color & 0x0000ff00) >> 8, alpha);
/*
* Draw
*/
result = _filledRectAlpha(dst, x1, y1, x2, y2, mcolor, alpha);
/*
* Unlock the surface
*/
if (SDL_MUSTLOCK(dst)) {
SDL_UnlockSurface(dst);
}
return (result);
}
/*!
\brief Internal function to draw horizontal line of RGBA color with alpha blending.
\param dst The surface to draw on.
\param x1 X coordinate of the first point (i.e. left) of the line.
\param x2 X coordinate of the second point (i.e. right) of the line.
\param y Y coordinate of the points of the line.
\param color The color value of the line to draw (0xRRGGBBAA).
\returns Returns 0 on success, -1 on failure.
*/
int _HLineAlpha(SDL_Surface * dst, Sint16 x1, Sint16 x2, Sint16 y, Uint32 color)
{
return (filledRectAlpha(dst, x1, y, x2, y, color));
}
/*!
\brief Internal function to draw vertical line of RGBA color with alpha blending.
\param dst The surface to draw on.
\param x X coordinate of the points of the line.
\param y1 Y coordinate of the first point (top) of the line.
\param y2 Y coordinate of the second point (bottom) of the line.
\param color The color value of the line to draw (0xRRGGBBAA).
\returns Returns 0 on success, -1 on failure.
*/
int _VLineAlpha(SDL_Surface * dst, Sint16 x, Sint16 y1, Sint16 y2, Uint32 color)
{
return (filledRectAlpha(dst, x, y1, x, y2, color));
}
/*!
\brief Pixel draw with blending enabled and using alpha weight on color.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param color The color value of the pixel to draw (0xRRGGBBAA).
\param weight The weight multiplied into the alpha value of the pixel.
\returns Returns 0 on success, -1 on failure.
*/
int pixelColorWeight(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color, Uint32 weight)
{
Uint32 a;
/*
* Get alpha
*/
a = (color & (Uint32) 0x000000ff);
/*
* Modify Alpha by weight
*/
a = ((a * weight) >> 8);
return (pixelColor(dst, x, y, (color & (Uint32) 0xffffff00) | (Uint32) a));
}
/*!
\brief Pixel draw with blending enabled and using alpha weight on color - no locking.
\param dst The surface to draw on.
\param x The horizontal coordinate of the pixel.
\param y The vertical position of the pixel.
\param color The color value of the pixel to draw (0xRRGGBBAA).
\param weight The weight multiplied into the alpha value of the pixel.
\returns Returns 0 on success, -1 on failure.
*/
int pixelColorWeightNolock(SDL_Surface * dst, Sint16 x, Sint16 y, Uint32 color, Uint32 weight)
{
Uint32 a;
/*
* Get alpha
*/
a = (color & (Uint32) 0x000000ff);
/*
* Modify Alpha by weight
*/
a = ((a * weight) >> 8);
return (pixelColorNolock(dst, x, y, (color & (Uint32) 0xffffff00) | (Uint32) a));
}
/*!
\brief Pixel draw with blending enabled if a<255.
\param dst The surface to draw on.
\param x X (horizontal) coordinate of the pixel.
\param y Y (vertical) coordinate of the pixel.
\param r The red color value of the pixel to draw.
\param g The green color value of the pixel to draw.
\param b The blue color value of the pixel to draw.
\param a The alpha value of the pixel to draw.
\returns Returns 0 on success, -1 on failure.
*/
int pixelRGBA(SDL_Surface * dst, Sint16 x, Sint16 y, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
{
Uint32 color;
/*
* Check Alpha