问题描述
texturelod 的LOD参数取什么值??我发现的规格根本没有提及.它是百分比还是带有百分比的索引值.如果是后者，是否有办法获取纹理具有的mipmap的数量，以便我可以使用一个百分比?
What value does the LOD parameter take for texturelod? The spec I found doesn't mention it at all. Is it a percentage or an index value with a percent. If the later is the case, is there a way to get the number of mipmaps the texture has so that I would be able to use a percentage?
推荐答案
LOD参数指定mipmap级别，四舍五入到最接近的整数.请记住，OpenGL指定了mipmap级别，例如0表示最大，而数字越小.
The LOD parameter specifies the mipmap level, rounded to the nearest whole number. Remember that OpenGL specifies mipmap levels, such that 0 is the largest, with increasing numbers going smaller.
但是，此处指定的LOD总是 相对于当前 GL_TEXTURE_BASE_LEVEL 纹理.因此，如果您使用 textureLod(...，0)，并且基本级别设置为mipmap 2，则将从mipmap级别2中进行选择.您也不能在之外选择mipmap.GL_TEXTURE_MAX_LEVEL 范围；系统将自动适当钳位指定的参数.
However, the LOD specified here will always be relative to the current GL_TEXTURE_BASE_LEVEL of the texture. So if you use textureLod(..., 0), and the base level is set to mipmap 2, then you will select from mipmap level 2. You also cannot select mipmaps outside of the GL_TEXTURE_MAX_LEVEL range; the system will automatically clamp the specified parameter appropriately.
这篇关于着色器TextureLod参数值?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！