diff options
| -rw-r--r-- | engines/dreamweb/stubs.cpp | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/engines/dreamweb/stubs.cpp b/engines/dreamweb/stubs.cpp index 49b0012927..1bad368d43 100644 --- a/engines/dreamweb/stubs.cpp +++ b/engines/dreamweb/stubs.cpp @@ -568,10 +568,24 @@ void DreamGenContext::frameoutv() { */ void DreamGenContext::frameoutv(uint8* dst, const uint8* src, uint16 pitch, uint16 width, uint16 height, uint16 x, uint16 y) { + // NB : These resilience checks were not in the original engine, but did they result in undefined behaviour + // or was something broken during porting to C++? + assert(pitch == 320); + + if(x >= 320) + return; + if(y >= 200) + return; + if(x + width > 320) { + width = 320 - x; + } + if(y + height > 200) { + height = 200 - y; + } + uint16 stride = pitch - width; dst += pitch * y + x; - // NB: Original code assumes non-zero width and height, "for" are unneeded, do-while would suffice but would be less readable for (uint16 j = 0; j < height; ++j) { for (uint16 i = 0; i < width; ++i) { uint8 pixel = *src++; @@ -659,7 +673,7 @@ uint16 DreamGenContext::showframeCPP(uint16 dst, uint16 src, uint16 x, uint16 y, } //noeffects: es = data.word(kWorkspace); - frameoutv(es.ptr(0, 320 * height), ds.ptr(si, width * height), 320, width, height, di, bx); + frameoutv(es.ptr(0, 65536), ds.ptr(si, width * height), 320, width, height, di, bx); return written; } |