| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org> |
| |
| 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. |
| */ |
| #include "../SDL_internal.h" |
| |
| #include "SDL_video.h" |
| #include "SDL_blit.h" |
| #include "SDL_blit_slow.h" |
| |
| #define FORMAT_ALPHA 0 |
| #define FORMAT_NO_ALPHA -1 |
| #define FORMAT_2101010 1 |
| #define FORMAT_HAS_ALPHA(format) format == 0 |
| #define FORMAT_HAS_NO_ALPHA(format) format < 0 |
| static int SDL_INLINE detect_format(SDL_PixelFormat *pf) |
| { |
| if (pf->format == SDL_PIXELFORMAT_ARGB2101010) { |
| return FORMAT_2101010; |
| } else if (pf->Amask) { |
| return FORMAT_ALPHA; |
| } else { |
| return FORMAT_NO_ALPHA; |
| } |
| } |
| |
| /* The ONE TRUE BLITTER |
| * This puppy has to handle all the unoptimized cases - yes, it's slow. |
| */ |
| void SDL_Blit_Slow(SDL_BlitInfo *info) |
| { |
| const int flags = info->flags; |
| const Uint32 modulateR = info->r; |
| const Uint32 modulateG = info->g; |
| const Uint32 modulateB = info->b; |
| const Uint32 modulateA = info->a; |
| Uint32 srcpixel; |
| Uint32 srcR, srcG, srcB, srcA; |
| Uint32 dstpixel; |
| Uint32 dstR, dstG, dstB, dstA; |
| int srcy, srcx; |
| Uint32 posy, posx; |
| int incy, incx; |
| SDL_PixelFormat *src_fmt = info->src_fmt; |
| SDL_PixelFormat *dst_fmt = info->dst_fmt; |
| int srcbpp = src_fmt->BytesPerPixel; |
| int dstbpp = dst_fmt->BytesPerPixel; |
| int srcfmt_val; |
| int dstfmt_val; |
| Uint32 rgbmask = ~src_fmt->Amask; |
| Uint32 ckey = info->colorkey & rgbmask; |
| |
| srcfmt_val = detect_format(src_fmt); |
| dstfmt_val = detect_format(dst_fmt); |
| |
| incy = (info->src_h << 16) / info->dst_h; |
| incx = (info->src_w << 16) / info->dst_w; |
| posy = incy / 2; /* start at the middle of pixel */ |
| |
| while (info->dst_h--) { |
| Uint8 *src = 0; |
| Uint8 *dst = info->dst; |
| int n = info->dst_w; |
| posx = incx / 2; /* start at the middle of pixel */ |
| srcy = posy >> 16; |
| while (n--) { |
| srcx = posx >> 16; |
| src = (info->src + (srcy * info->src_pitch) + (srcx * srcbpp)); |
| |
| if (FORMAT_HAS_ALPHA(srcfmt_val)) { |
| DISEMBLE_RGBA(src, srcbpp, src_fmt, srcpixel, srcR, srcG, srcB, srcA); |
| } else if (FORMAT_HAS_NO_ALPHA(srcfmt_val)) { |
| DISEMBLE_RGB(src, srcbpp, src_fmt, srcpixel, srcR, srcG, srcB); |
| srcA = 0xFF; |
| } else { |
| /* SDL_PIXELFORMAT_ARGB2101010 */ |
| srcpixel = *((Uint32 *)(src)); |
| RGBA_FROM_ARGB2101010(srcpixel, srcR, srcG, srcB, srcA); |
| } |
| |
| if (flags & SDL_COPY_COLORKEY) { |
| /* srcpixel isn't set for 24 bpp */ |
| if (srcbpp == 3) { |
| srcpixel = (srcR << src_fmt->Rshift) | |
| (srcG << src_fmt->Gshift) | (srcB << src_fmt->Bshift); |
| } |
| if ((srcpixel & rgbmask) == ckey) { |
| posx += incx; |
| dst += dstbpp; |
| continue; |
| } |
| } |
| if ((flags & (SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD | SDL_COPY_MUL))) { |
| if (FORMAT_HAS_ALPHA(dstfmt_val)) { |
| DISEMBLE_RGBA(dst, dstbpp, dst_fmt, dstpixel, dstR, dstG, dstB, dstA); |
| } else if (FORMAT_HAS_NO_ALPHA(dstfmt_val)) { |
| DISEMBLE_RGB(dst, dstbpp, dst_fmt, dstpixel, dstR, dstG, dstB); |
| dstA = 0xFF; |
| } else { |
| /* SDL_PIXELFORMAT_ARGB2101010 */ |
| dstpixel = *((Uint32 *) (dst)); |
| RGBA_FROM_ARGB2101010(dstpixel, dstR, dstG, dstB, dstA); |
| } |
| } else { |
| /* don't care */ |
| dstR = dstG = dstB = dstA = 0; |
| } |
| |
| if (flags & SDL_COPY_MODULATE_COLOR) { |
| srcR = (srcR * modulateR) / 255; |
| srcG = (srcG * modulateG) / 255; |
| srcB = (srcB * modulateB) / 255; |
| } |
| if (flags & SDL_COPY_MODULATE_ALPHA) { |
| srcA = (srcA * modulateA) / 255; |
| } |
| if (flags & (SDL_COPY_BLEND | SDL_COPY_ADD)) { |
| /* This goes away if we ever use premultiplied alpha */ |
| if (srcA < 255) { |
| srcR = (srcR * srcA) / 255; |
| srcG = (srcG * srcA) / 255; |
| srcB = (srcB * srcA) / 255; |
| } |
| } |
| switch (flags & (SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD | SDL_COPY_MUL)) { |
| case 0: |
| dstR = srcR; |
| dstG = srcG; |
| dstB = srcB; |
| dstA = srcA; |
| break; |
| case SDL_COPY_BLEND: |
| dstR = srcR + ((255 - srcA) * dstR) / 255; |
| dstG = srcG + ((255 - srcA) * dstG) / 255; |
| dstB = srcB + ((255 - srcA) * dstB) / 255; |
| dstA = srcA + ((255 - srcA) * dstA) / 255; |
| break; |
| case SDL_COPY_ADD: |
| dstR = srcR + dstR; |
| if (dstR > 255) { |
| dstR = 255; |
| } |
| dstG = srcG + dstG; |
| if (dstG > 255) { |
| dstG = 255; |
| } |
| dstB = srcB + dstB; |
| if (dstB > 255) { |
| dstB = 255; |
| } |
| break; |
| case SDL_COPY_MOD: |
| dstR = (srcR * dstR) / 255; |
| dstG = (srcG * dstG) / 255; |
| dstB = (srcB * dstB) / 255; |
| break; |
| case SDL_COPY_MUL: |
| dstR = ((srcR * dstR) + (dstR * (255 - srcA))) / 255; |
| if (dstR > 255) { |
| dstR = 255; |
| } |
| dstG = ((srcG * dstG) + (dstG * (255 - srcA))) / 255; |
| if (dstG > 255) { |
| dstG = 255; |
| } |
| dstB = ((srcB * dstB) + (dstB * (255 - srcA))) / 255; |
| if (dstB > 255) { |
| dstB = 255; |
| } |
| break; |
| } |
| if (FORMAT_HAS_ALPHA(dstfmt_val)) { |
| ASSEMBLE_RGBA(dst, dstbpp, dst_fmt, dstR, dstG, dstB, dstA); |
| } else if (FORMAT_HAS_NO_ALPHA(dstfmt_val)) { |
| ASSEMBLE_RGB(dst, dstbpp, dst_fmt, dstR, dstG, dstB); |
| } else { |
| /* SDL_PIXELFORMAT_ARGB2101010 */ |
| Uint32 pixel; |
| ARGB2101010_FROM_RGBA(pixel, dstR, dstG, dstB, dstA); |
| *(Uint32 *)dst = pixel; |
| } |
| posx += incx; |
| dst += dstbpp; |
| } |
| posy += incy; |
| info->dst += info->dst_pitch; |
| } |
| } |
| |
| /* vi: set ts=4 sw=4 expandtab: */ |
