sdlpixel.h File Reference

(986a3bf)

#include "gui/color.h"
#include <SDL.h>

Go to the source code of this file.

Functions
void	SDLputPixel (SDL_Surface *surface, int x, int y, const Color &color)
unsigned int	SDLAlpha32 (const unsigned int src, const unsigned int dst, const unsigned char a)
unsigned short	SDLAlpha16 (const unsigned short src, const unsigned short dst, const unsigned char a, const SDL_PixelFormat *const f)
void	SDLputPixelAlpha (SDL_Surface *surface, int x, int y, const Color &color)

Function Documentation

SDLAlpha16()

unsigned short SDLAlpha16 ( const unsigned short  src, const unsigned short  dst, const unsigned char  a, const SDL_PixelFormat *const  f  )

inline

Blends two 16 bit colors together.

Parameters

src	the source color.
dst	the destination color.
a	alpha.

Definition at line 170 of file sdlpixel.h.

{
    unsigned int b = ((src & f->Rmask) * a + (dst & f->Rmask)
        * (255 - a)) >> 8;
    unsigned int g = ((src & f->Gmask) * a + (dst & f->Gmask)
        * (255 - a)) >> 8;
    unsigned int r = ((src & f->Bmask) * a + (dst & f->Bmask)
        * (255 - a)) >> 8;
 
    return static_cast<unsigned short>((b & f->Rmask)
        | (g & f->Gmask) | (r & f->Bmask));
}

Referenced by SDLputPixelAlpha().

SDLAlpha32()

unsigned int SDLAlpha32 ( const unsigned int  src, const unsigned int  dst, const unsigned char  a  )

inline

Blends two 32 bit colors together.

Parameters

src	the source color.
dst	the destination color.
a	alpha.

Definition at line 145 of file sdlpixel.h.

{
    const unsigned int b = ((src & 0xff) * a + (dst & 0xff) * (255 - a)) >> 8;
    const unsigned int g = ((src & 0xff00) * a + (dst & 0xff00)
        * (255 - a)) >> 8;
    const unsigned int r = ((src & 0xff0000) * a + (dst & 0xff0000)
        * (255 - a)) >> 8;
 
    return (b & 0xff) | (g & 0xff00) | (r & 0xff0000);
}

Referenced by SDLputPixelAlpha().

SDLputPixel()

void SDLputPixel ( SDL_Surface *  surface, int  x, int  y, const Color &  color  )

inline

Puts a pixel on an SDL_Surface.

Parameters

x	the x coordinate on the surface.
y	the y coordinate on the surface.
color	the color the pixel should be in.

Definition at line 86 of file sdlpixel.h.

{
    if (surface == nullptr)
        return;
 
    const int bpp = surface->format->BytesPerPixel;
 
    SDL_LockSurface(surface);
 
    Uint8 *const p = static_cast<uint8_t*>(surface->pixels)
        + CAST_SIZE(y * surface->pitch + x * bpp);
 
    const Uint32 pixel = SDL_MapRGB(surface->format,
        CAST_U8(color.r), CAST_U8(color.g),
        CAST_U8(color.b));
 
    switch (bpp)
    {
        case 1:
            *p = CAST_U8(pixel);
            break;
 
        case 2:
            *reinterpret_cast<uint16_t*>(p) = CAST_U16(pixel);
            break;
 
        case 3:
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
            p[0] = CAST_U8((pixel >> 16) & 0xff);
            p[1] = CAST_U8((pixel >> 8) & 0xff);
            p[2] = CAST_U8((pixel) & 0xff);
#else  // SDL_BYTEORDER == SDL_BIG_ENDIAN
 
            p[0] = CAST_U8((pixel) & 0xff);
            p[1] = CAST_U8((pixel >> 8) & 0xff);
            p[2] = CAST_U8((pixel >> 16) & 0xff);
#endif  // SDL_BYTEORDER == SDL_BIG_ENDIAN
 
            break;
 
        case 4:
            *reinterpret_cast<Uint32*>(p) = pixel;
            break;
 
        default:
            break;
    }
 
    SDL_UnlockSurface(surface);
}

References Color::b, CAST_SIZE, CAST_U16, CAST_U8, Color::g, Color::r, x, and y.

SDLputPixelAlpha()

void SDLputPixelAlpha ( SDL_Surface *  surface, int  x, int  y, const Color &  color  )

inline

Puts a pixel on an SDL_Surface with alpha

Parameters

x	the x coordinate on the surface.
y	the y coordinate on the surface.
color	the color the pixel should be in.

Definition at line 193 of file sdlpixel.h.

{
    if (surface == nullptr)
        return;
    const int bpp = surface->format->BytesPerPixel;
 
    SDL_LockSurface(surface);
 
    Uint8 *const p = static_cast<uint8_t*>(surface->pixels)
        + CAST_SIZE(y * surface->pitch + x * bpp);
 
    const Uint32 pixel = SDL_MapRGB(surface->format,
        CAST_U8(color.r),
        CAST_U8(color.g),
        CAST_U8(color.b));
 
    switch (bpp)
    {
        case 1:
            *p = CAST_U8(pixel);
            break;
 
        case 2:
            *reinterpret_cast<Uint16*>(p) = SDLAlpha16(
                static_cast<unsigned short>(pixel),
                *reinterpret_cast<unsigned short*>(p),
                CAST_U8(color.a), surface->format);
            break;
 
        case 3:
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
            p[2] = CAST_U8((p[2] * (255 - color.a)
                + color.b * color.a) >> 8);
            p[1] = CAST_U8((p[1] * (255 - color.a)
                + color.g * color.a) >> 8);
            p[0] = CAST_U8((p[0] * (255 - color.a)
                + color.r * color.a) >> 8);
#else  // SDL_BYTEORDER == SDL_BIG_ENDIAN
 
            p[0] = CAST_U8((p[0] * (255 - color.a)
                + color.b * color.a) >> 8);
            p[1] = CAST_U8((p[1] * (255 - color.a)
                + color.g * color.a) >> 8);
            p[2] = CAST_U8((p[2] * (255 - color.a)
                + color.r * color.a) >> 8);
#endif  // SDL_BYTEORDER == SDL_BIG_ENDIAN
 
            break;
 
        case 4:
            *reinterpret_cast<Uint32*>(p) = SDLAlpha32(pixel,
                *reinterpret_cast<Uint32*>(p),
                CAST_U8(color.a));
            break;
        default:
            break;
    }
 
    SDL_UnlockSurface(surface);
}

References Color::a, Color::b, CAST_SIZE, CAST_U8, Color::g, Color::r, SDLAlpha16(), SDLAlpha32(), x, and y.