SGE介绍[原创]

SGE是SDL Graphics Extension (SGE)的缩写.SGE是一个SDL的附加图形库,SGE提供象素操作,基本图形,字体渲染,旋转缩放等功能.它由十个部分组成,我就不一一说了.总之,我认为他是对SDL现有库的重要补充,在游戏开发中,能够将原来通过SDL做的工作简化了许多.例如用SDL无法直接画线,输出文字,但是通过这个库,可以极大地简化操作.

SGE官方网站
由于作者时间原因,未将其翻译,望谅解.
详细内容请访问
1. Intro
SGE is an add-on graphics library for the Simple Direct Media Layer. SGE provides pixel operations, graphics primitives, FreeType rendering, rotation/scaling and much more.

This is free software (LGPL), read LICENSE for details.

SGE has the following parts:

[sge_surface] - Pixel operations, blitting and some pallete stuff.
[sge_primitives] - Drawing primitives such as lines and circles.
[sge_tt_text] - FreeType font support.
[sge_bm_text] - Bitmapfont and SFont support.
[sge_textpp] - Classes for handling and rendering text.
[sge_shape] - Classes for blitting and sprites.
[sge_collision] - Basic collision detection.
[sge_rotation] - Rotation and scaling of surfaces.
[sge_blib] - Filled, gourand shaded and texture mapped polygons.
[sge_misc] - Random number and delay functions.

Read docs/index.html for API documentation.

Always check WhatsNew for important (API) changes!

There is a "Beginners guide to SGE" in this documentation about how to compile and use SGE in your own project, please read it if you're new to Unix/Linux development.

Read INSTALL for quick compile and install instructions.

2. Requirements
GNU Make.
SDL 1.2+.
An ANSI/ISO C++ compiler. SGE should conform to ANSI/ISO C++.
Optional:
FreeType 2.x
SDL_Image (see section 5.3)
Some SDL knowledge.
First you need SDL and the FreeType (2.x) library (you only need the FreeType library if you want to use SGE's truetype font routines, see section 5.2). The FreeType library is included in most Linux distributions (RPM users: install the freetype dev rpm package from the install cd).

After installing SDL and FreeType, don't forget to check that the dynamic linker can find them (check /etc/ld.so.conf and run ldconfig).
You must also have a good C++ compiler (should be able to handle templates). Recent versions of GNU c++ works fine. SGE will use gcc/g++ as default, this can be changed in Makefile.conf.

 

3. Compiling
Before compiling you might want to change some Makefile.conf options, see section 5.

Just do 'make install' to compile and install SGE. This will install SGE to the same place as SDL. You can change the install *** by editing the PREFIX and PREFIX_H lines in the file "Makefile.conf".

If you just want to test the examples (and not install anything) you can just do 'make'. This will build a static version of SGE (libSGE.a).

If you want a dynamic version of SGE (libSGE.so) but don't want the makefile to install SGE, do 'make shared'.

To build the examples, goto the directory examples/ and do 'make'.

See the file INSTALL for more information. You can also read the "Beginners guide to SGE".

 

4. Library usage
Do ＃i nclude "sge.h" in your code after the normal ＃i nclude "SDL.h" line.

The normal way to compile code that uses SGE is with the flag `sdl-config --cflags`, but also add the flag -I/path/to/SGE/headers if the SGE headers are installed at any other place than the SDL headers.

The normal way to link code that uses SGE is with the flags -lSGE `sdl-config --libs` -lstdc++, but also add the flag -L/path/to/SGE/library if SGE is installed at any other place than SDL. If you're using static linking then the flags `freetype-config --libs` and/or -lSDL_image also needs to be added if FreeType and/or SDL_Image support is enabled.

Example:
g++ -Wall -O3 `sdl-config --cflags` -c my_sge_app.cxx
g++ -o my_sge_app my_sge_app.o -lSGE `sdl-config --libs` -lstdc++

See the "Beginners guide to SGE" and the code in examples/ for more information.

 

5. Makefile options
Edit Makefile.conf to turn on/off (y/n) these options.

5.1 Using pure C with SGE (C_COMP)
Setting 'C_COMP = y' should allow both C and C++ projects to use SGE. However, you will not be able to use any of the overloaded functions (only the Uint32 color version of the overloaded functions will be available) or C++ classes from a C project. C++ projects should not be affected. Default is 'y'.

5.2 FreeType (USE_FT)
If you don't need the TT font routines or just don't want do depend on FreeType, uncomment 'USE_FT = n' in Makefile.conf. Default behavior is to autodetect FreeType.

5.3 The SDL_Image library (USE_IMG)
The SDL_Image library SDL_Image will be autodetected with the default setting. SDL_Image support enables SGE to load png images and thus use Karl Bartel's very nice SFont bitmapfonts. The use of SDL_Image can also be controlled by setting 'USE_IMG = y/n' manually.

5.4 The QUIET option (QUIET)
Set QUIET = y if you don't want the makefile to output any SGE specific messages.

 

6. Cross compiling SGE to W32
SGE can be compiled by a win32 crosscompiler. You need a crosscompiled version of SDL (and FreeType or SDL_Image if used). Check SDL's documentation (README.Win32) on how to get and setup a cross-compiler.

A crosscompiler can be found at SDL's Mingw32 side. This crosscompiler uses the new MS C-Run-time library "msvcrt.dll", you can get it from Microsoft (do a keyword search for "libraries update") if you don't already have it.

If you want to build a dll ('cross-make dll' or 'dll-strip') then you might want to do 'ln -s ../../bin/i386-mingw32msvc-dllwrap dllwrap' in /usr/local/cross-tools/i386-mingw32msvc/bin.

7. Compiling SGE under W32 with MS VisC/C++
Should work. Check the download page on SGEs homepage for project files (these are untested by me and are often outdated but may be of some help).

Note that if you don't use the makefile system to build SGE (as with VisC/C++) then you must edit sge_config.h manually to change build options. The options in section 5 corresponds to defining the following symbols in sge_config.h:
_SGE_C_AND_CPP  - C_COMP=y
_SGE_NOTTF      - USE_FT=n
_SGE_HAVE_IMG   - USE_IMG=y

For example:
/* SGE Config header */
#define SGE_VER 030810
#define _SGE_C_AND_CPP
#define _SGE_HAVE_IMG

 

8. Misc.
Read the html documentation and study the examples.

 

Anders Lindstr?m