diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/resources/image.cpp | 57 |
1 files changed, 31 insertions, 26 deletions
diff --git a/src/resources/image.cpp b/src/resources/image.cpp index 8eaadcb94..86c5956ea 100644 --- a/src/resources/image.cpp +++ b/src/resources/image.cpp @@ -322,31 +322,30 @@ void Image::setAlpha(float alpha) SDL_LockSurface(mSDLSurface); // Precompute as much as possible - int maxHeight = std::min((mBounds.y + mBounds.h), mSDLSurface->h); - int maxWidth = std::min((mBounds.x + mBounds.w), mSDLSurface->w); - int i = 0; - - for (int y = mBounds.y; y < maxHeight; y++) + const int maxHeight = std::min((mBounds.y + mBounds.h), + mSDLSurface->h); + const int maxWidth = std::min((mBounds.x + mBounds.w), + mSDLSurface->w); + const int i1 = mBounds.y * mSDLSurface->w + mBounds.x; + const int i2 = (maxHeight - 1) * mSDLSurface->w + maxWidth - 1; + + for (int i = i1; i <= i2; i++) { - for (int x = mBounds.x; x < maxWidth; x++) + // Only change the pixel if it was visible at load time... + Uint8 sourceAlpha = mAlphaChannel[i]; + if (sourceAlpha > 0) { - i = y * mSDLSurface->w + x; - // Only change the pixel if it was visible at load time... - Uint8 sourceAlpha = mAlphaChannel[i]; - if (sourceAlpha > 0) - { - Uint8 r, g, b, a; - SDL_GetRGBA((static_cast<Uint32*> - (mSDLSurface->pixels))[i], - mSDLSurface->format, - &r, &g, &b, &a); + Uint8 r, g, b, a; + SDL_GetRGBA((static_cast<Uint32*> + (mSDLSurface->pixels))[i], + mSDLSurface->format, + &r, &g, &b, &a); - a = (Uint8) (static_cast<float>(sourceAlpha) * mAlpha); + a = (Uint8) (static_cast<float>(sourceAlpha) * mAlpha); - // Here is the pixel we want to set - (static_cast<Uint32 *>(mSDLSurface->pixels))[i] = - SDL_MapRGBA(mSDLSurface->format, r, g, b, a); - } + // Here is the pixel we want to set + (static_cast<Uint32 *>(mSDLSurface->pixels))[i] = + SDL_MapRGBA(mSDLSurface->format, r, g, b, a); } } @@ -377,15 +376,19 @@ Image* Image::SDLmerge(Image *image, int x, int y) SDL_LockSurface(surface); SDL_LockSurface(mSDLSurface); + + const int x0 = (y * getWidth()) + x; + const int maxX = std::min(image->getWidth(), getWidth() - x); + const int maxY = std::min(image->getHeight(), getHeight() - y); + // for each pixel lines of a source image - for (offset_x = (x > 0 ? 0 : -x); offset_x < image->getWidth() && - x + offset_x < getWidth(); offset_x++) + for (offset_x = (x > 0 ? 0 : -x); offset_x < maxX; offset_x++) { - for (offset_y = (y > 0 ? 0 : -y); offset_y < image->getHeight() - && y + offset_y < getHeight(); offset_y++) + const int x1 = x0 + offset_x; + for (offset_y = (y > 0 ? 0 : -y); offset_y < maxY; offset_y++) { // Computing offset on both images - current_offset = (y + offset_y) * getWidth() + x + offset_x; + current_offset = (offset_y * getWidth()) + x1; surface_offset = offset_y * surface->w + offset_x; // Retrieving a pixel to merge @@ -408,8 +411,10 @@ Image* Image::SDLmerge(Image *image, int x, int y) // new pixel with no alpha or nothing on previous pixel if (a == SDL_ALPHA_OPAQUE || (p_a == 0 && a > 0)) + { ((Uint32 *)(surface->pixels))[current_offset] = SDL_MapRGBA(current_fmt, r, g, b, a); + } else if (a > 0) { // alpha is lower => merge color with previous value f_a = static_cast<double>(a) / 255.0; |