From: "Alex Volkov" Date: Thu, 10 Nov 2005 21:53:40 -0500 Subject: [SDL] BUG[?]: 32bpp RGBA->RGB colorkey blit, no SDL_SRCALPHA It seems there is either a documentation vs. reality mismatch or a real bug in SDL_blit_N.c:BlitNtoNKey(). The exact blit in question is a 32bpp RGBA->RGB, where RGBA has SDL_COLORKEY and *no* SDL_SRCALPHA flags. The doc in SDL_video.h states: * RGBA->RGB: * SDL_SRCALPHA not set: * copy RGB. * if SDL_SRCCOLORKEY set, only copy the pixels matching the * RGB values of the source colour key, ignoring alpha in the * comparison. BlitNtoNKey(), however, forgets to "ignore alpha in the comparison". The documentation makes perfect sense, so I think it is the code that is faulty. The attached patch corrects the code.

# Makefile to build the SDL library

INCLUDE = -I./include
CFLAGS  = -g -O2 $(INCLUDE)
AR	= ar
RANLIB	= ranlib

TARGET  = libSDL.a
SOURCES = \
	src/*.c \
	src/audio/*.c \
	src/cdrom/*.c \
	src/cpuinfo/*.c \
	src/events/*.c \
	src/file/*.c \
	src/joystick/*.c \
	src/stdlib/*.c \
	src/thread/*.c \
	src/timer/*.c \
	src/video/*.c \
	src/audio/dummy/*.c \
	src/video/dummy/*.c \
	src/joystick/dummy/*.c \
	src/cdrom/dummy/*.c \
	src/thread/generic/*.c \
	src/timer/dummy/*.c \
	src/loadso/dummy/*.c \

OBJECTS = $(shell echo $(SOURCES) | sed -e 's,\.c,\.o,g')

all: $(TARGET)

$(TARGET): $(OBJECTS)
	$(AR) crv $@ $^
	$(RANLIB) $@

clean:
	rm -f $(TARGET) $(OBJECTS)