如何使用 OpenGL 获得 Cg 着色器的统一位置？
我之前使用 GLSL 方式涉足过基本的着色器编程。现在我又回到了它，使用 Cg 着色器。按照 Josh Beam 网站上的教程，我已经实现了所需的功能，能够更改我的着色器，但是我无法在 OpenGL 端操纵其中的制服。
GLuint handle;
::glGenProgramsARB(1, &handle);
::glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, handle);
::glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, strlen(pSource), pSource);
while(true)
{
::glEnable(GL_FRAGMENT_PROGRAM_ARB);
::glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, handle);
// render
::glDisable(GL_FRAGMENT_PROGRAM_ARB);
// present backbuffer
}
工作完美。如果我尝试 ::glGetUniformLocationARB(handle, pUniformName)，我会收到 GL_INVALID_VALUE 错误。尝试在创建着色器后和绑定后执行此操作，以获得相同的结果。我也尝试过 ::glUseProgramObjectARB(handle)，正如不同来源建议的那样，但这也不起作用，并且似乎属于 GLSL 方式（Lighthouse3D 教程）。
我已经仔细检查过制服名称是否正确。
我还找到了一种方法（NeHe 教程），涉及 #include-ing Cg标头和调用 cg API。使用 OpenGL API 无法实现这一点吗？ （这样做的原因是极简主义；我想让这个功能成为静态库的一部分，并且我全力以赴最大限度地减少编译/链接依赖项的数量。）
I've dabbled with basic shader programming before, using the GLSL way. Now I've come back to it, using Cg shaders. Following the tutorial at Josh Beam's website I've achieved the desired functionality, was able to change my shader around, however I couldn't manipulate the uniforms in it on the OpenGL side.
GLuint handle;
::glGenProgramsARB(1, &handle);
::glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, handle);
::glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, strlen(pSource), pSource);
while(true)
{
::glEnable(GL_FRAGMENT_PROGRAM_ARB);
::glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, handle);
// render
::glDisable(GL_FRAGMENT_PROGRAM_ARB);
// present backbuffer
}
Works perfectly. If I try to ::glGetUniformLocationARB(handle, pUniformName), I get a GL_INVALID_VALUE error. Tried to do this both after creating the shader, and after binding, to the same outcome. I have also tried to ::glUseProgramObjectARB(handle), as different sources suggested, however this didn't work either, and seems to belong to the GLSL way (Lighthouse3D tutorials).
I have double-checked that the uniform name is correct.
I have also found an approach (NeHe tutorials), that involves #include-ing Cg headers and calling cg APIs. Is this not doable using OpenGL API-s? (The reason for this is minimalism; I want to make this functionality a part of a static library, and I'm all for minimising the number of compiling / linking dependencies.)
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您混淆了不同的扩展名。
术语“uniform”是指使用
uniform关键字声明的 GLSL 全局变量。 ARB 装配着色器没有制服。他们有类似的概念，但他们不称其为“制服”。glGetUniformLocationARB是一个 GLSL 函数。它们的 ARB 程序集术语是“程序本地参数”。这些自然是由glProgramLocalParameterARB系列函数设置的。哦，你永远不应该使用任何以 ARB 结尾的 GLSL 函数。 曾经。
You are confusing different extensions.
The term "uniform" refers to GLSL global variables declared with the
uniformkeyword. ARB assembly shaders do not have uniforms. They have a similar concept, but they don't call them "uniforms".glGetUniformLocationARBis a GLSL function. The ARB assembly term for them is "program local parameter". These are naturally set by theglProgramLocalParameterARBseries of functions.Oh, and you should never use any GLSL functions that end in ARB. Ever.