Ork, for OpenGL rendering kernel, provides a C++ API on top of OpenGL, which greatly simplifies the development of 3D applications.
Suppose that you want to draw a mesh in an offscreen framebuffer, with a program that uses a texture. Assuming that these objects are already created, with the OpenGL API you need something like this:
glUseProgram(myProgram);
glActiveTexture(GL_TEXTURE0 + myUnit);
glBindTexture(GL_TEXTURE_2D, myTexture);
glUniform1i(glGetUniformLocation(myProgram, "mySampler"), myUnit);
glBindBuffer(GL_ARRAY_BUFFER, myVBO);
glVertexAttribPointer(0, 4, GL_FLOAT, false, 16, 0);
glEnableVertexAttribArray(0);
glBindFramebuffer(GL_FRAMEBUFFER, myFramebuffer);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);With the Ork API you simply need two steps (and the first one does not need to be repeated before each draw, unless you want a different texture for each draw):
myProgram->getUniformSampler("mySampler")->set(myTexture);
myFramebuffer->draw(myProgram, *myMesh);Notes:
When compiling with CMake, a
-DCMAKE_INSTALL_PREFIX=option is recommended. For spaces may cause include errors or NOTFOUND errors, install prefix should be a path without spaces.
提示：
使用CMake进行编译时，建议使用
-DCMAKE_INSTALL_PREFIX=指定安装路径。安装路径中存在空格可能导致错误，建议指定不含空格的安装路径。
.pc files should be found in env PKG_CONFIG_PATH.
Chocolatey provides the pkg-config command on Windows.
通过 Chocolatey 包管理器安装Windows版本的 pkg-config 命令。
CMake命令会调用 pkg-config ，在 PKG_CONFIG_PATH 环境变量中查找 .pc 文件，自动生成 _INCLUDE_DIRS 和 _LIBRARY_DIRS 的CMake变量。
所有代码编译时使用同一的 Win32 或 X64 配置。
Libraries required for ork is listed as follows:
- Glew
- GLU (Provided by OS).
- OpenGL (Provided by OS).
- GLFW.
- FreeGLUT.
- AntTweakBar (Required by proland project).
- pThreads.
- TIFF (Required by proland project).
Glew's homepage is Glew.
For VS2017 or VS2019, the Perlmint fork should be preferred.
A command line example to generate Visual Studio project is showing as follows:
cmake ./cmake -Bvs16 -DCMAKE_INSTALL_PREFIX=bin/ -G"Visual Studio 16 2019"Glu is required by Glew.
Glu's source can be get from MESA.
For the
GLU32lib has been provided by Windows, we should comment therequireslibparameter in CMakeLists.txt.# set (requireslib glu)
使用 Perlmint 的Glew fork以使用CMake进行编译。同时生成.pc文件以便Proland通过pkg-config命令引用。
GLFW3 can be download from the GLFW official site.
下载后使用CMake进行编译，通过pkg-config命令引用include和lib路径。
Glut has been deprecated. Use freeglut instead.
Freeglut can be get from HERE or unofficial repo on github.
建议通过GitHub下载后，使用CMake进行编译，通过pkg-config命令引用include和lib路径。
AntTweakBar is required by proland project
AntTweakBar should use the version modified by me in this repo.
AntTweakBar的pre-build二进制中编译了使用 texture2D 的shader，会导致demo编译时崩溃。下载后打开 AntTweakBar_VS2012.sln 使用Visual Studio进行编译即可。
Pthreads-win32 currently implements a large subset of the POSIX standard threads related API. The latest version is 2.9.1(2012-05-27).
The source tree and precompiled .DLL, .LIB and necessary header files are included in the zip file named "pthread-w32-v-v-v-release.zip" at: ftp://sourceware.org/pub/pthreads-win32.
Unzip the zip file and set the include dirs and lib dirs inside Pre-built.2 folder.
Add the following line to the top of header file pthreads.h to avoid timespec re-definition error:
#define HAVE_STRUCT_TIMESPEC 1根据以下选项使用相应的pThreads库：
In general:
pthread[VG]{SE,CE,C}[c].dll
pthread[VG]{SE,CE,C}[c].lib
where:
[VG] indicates the compiler
V - MS VC, or
G - GNU C
{SE,CE,C} indicates the exception handling scheme
SE - Structured EH, or
CE - C++ EH, or
C - no exceptions - uses setjmp/longjmp
c - DLL compatibility number indicating ABI and API
compatibility with applications built against
a snapshot with the same compatibility number.
See 'Version numbering' below.
在 CMake 指定安装路径时，include路径指定 Pre-built.2 路径下的 include 文件夹；lib路径指定 lib 下的 x86 （Win32）或 x64 (X64)路径。
LibTIFF is required by proland project
Tiff is library and tools for TIFF images.
The Master HTTP Site http://www.remotesensing.org/libtiff has been deprecated.
The latest version of libtiff on site http://www.libtiff.org/ is v3.6.1, while the version of Tiff for Windows is v3.8.2.
The GnuWin32 distribution comes in two versions. The ordinary version uses the standard Unix equivalents, such as fopen and read, for input and output, the other version (Tiff-win32) uses the Win32 API functions, such as CreateFile and ReadFile, for input and output. The ordinary version (Tiff) is more suitable for porting Unix programs, the Win32-API version is more suitable for writing Win32 programs.
When we clicked the Mirror Download Site http://libtiff.maptools.org/dl/, a redirection to http://download.osgeo.org/libtiff is performed. The latest version of libtiff can be found in the mirror site is v4.3.0rc1 which released on 2021-Apr-16.
It seems that the SimpleSystems hold the latest libtiff: http://www.simplesystems.org/libtiff/.
Libtiff v3.6.1 does not have a CMakeLists.txt, we use v4.3.0 instead.
Zlib1 and JPEG62 are recomended. Or, TIFF warning would show up.
TBD: TIFF编译建议指定使用 zlib 和 JPEG 库，否则在运行 demo 时会有相关 Warning 并引起渲染错误。
I am playing with integrating Proland in a project, and Proland runs on Ork. Since Ork does not allways build and run out of the box, the are some modifications to be done.