OpenGL 的glDisable(GL_TEXTURE_2D)函数和glBindTexture(GL_TEXTURE_2D,0)有什么区别？
OpenGL glDisable(GL_TEXTURE_2D) vs glBindTexture(GL_TEXTURE_2D,0)
These are two fundamentally different things.
glDisable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D,0)
glDisable (GL_TEXTURE_2D)
- Disables 2D textures for the active Texture Unit in the fixed-function OpenGL pipeline.
- In programmable OpenGL (GLSL or the older ARB VP/FP assembly languages), enabling or disabling GL_TEXTURE_2D is meaningless.
glBindTexture (GL_TEXTURE_2D,0)
- Binds the "default" texture to the active Texture Image Unit.
- For all intents and purposes, there is always a texture bound to a Texture Image Unit; 0 is just a special-case with an initially incomplete set of states, thus complicating validation (see below).
There is a little bit of validation overhead associated with binding any OpenGL resource (GLSL programs and FBOs tend to have the most complicated validation). In general,
Therefore,
If your intention by binding 0 was simply to "disable" a texture, you would be better off setting a uniform value to communicate this intent to a shader. Uniforms are extremely cheap to set (assuming you do not do something stupid like query their location everytime you set them). Changing a uniform is orders of magnitude quicker than binding a different texture or even worse a different GLSL program.
If you are using fixed-function OpenGL: OpenGL1.0
- Disabling GL_TEXTURE_2D is a better way of approaching this problem.
- Changing bound objects should be done as little as possible.
If you are using programmable OpenGL: OpenGL2.0
- Neither of these things make much sense.
- Work your desired behavior into your shaders.
