本文介绍了如何使用Alpha渲染纹理?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
如何使用Alpha渲染纹理?
How to render a texture with alpha?
我有一个纹理,需要在不同位置使用不同的alpha值渲染它.有办法吗? (我的纹理是GL_RGBA)
I have a texture, and need to render it with different alpha values at different locations. Any way to do so? (My texture is GL_RGBA)
如果无法即时更改Alpha值,我必须为不同的Alpha级别创建不同的纹理吗?
If not possible to change alpha value on the fly, I have to create different textures for different alpha levels?
推荐答案
您的纹理为GL_RGBA,因此每个纹理像素具有不同的alpha值.
Your texture is GL_RGBA so it has a different alpha value for each texel.
如果要更改用于渲染的alpha值,我可以考虑以下方法:
If you want to change the alpha value used for render, I can think of the following methods:
- 更改纹理的alpha值(不确定是否要说的话).
- 使用
glColor4f
更改顶点的alpha值.它将乘以纹理值.您可能需要使用glEnable(GL_COLOR_MATERIAL)
和/或glColorMaterial()
. - 使用顶点着色器更改顶点alpha值.它将乘以纹理值.
- 使用片段着色器动态更改采样的纹理值.
- 使用两个纹理阶段并将其相乘.第二个将具有修改后的alpha值(请参见
glActiveTexture()
和朋友). - 使用片段着色器和两个(或更多)纹理阶段.这是最酷的!
- Change the texture alpha values (not sure if you say that you don't want to do that).
- Use
glColor4f
to change the alpha value of the vertices. It will multiply the texture values. You may need to useglEnable(GL_COLOR_MATERIAL)
and/orglColorMaterial()
. - Use a vertex shader to change the vertex alpha values. It will multiply the texture values.
- Use a fragment shader to change the sampled texture values on the fly.
- Use two texture stages and multiply them. The second one will have the modified alpha values (see
glActiveTexture()
and friends). - Use a fragment shader and two (or more) texture stages. This is the coolest!
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