Hi

as a shader newbie, I want to use a existing shader but don't understand to begin those:

// textures

uniform sampler2D u_textureFg;

uniform sampler2D u_textureBg;

…

// alpha-blends two colors

vec4 blend(vec4 bg,vec4 fg){

…

How should I give a loaded texture to for ex:

uniform sampler2D u_textureBg;

Why is it later only named bg and not u_textureBg?

Many thanks

You might need to start with some HLSL basics, for example this could work: http://rbwhitaker.wikidot.com/hlsl-tutorials​

Answering your question(s):

• uniform means you can update it from outside the shader
• the names of variables can be many things ?
• the vec4 bg is a 4d vector, the u_textureBg is a texture sampler, which is used to determine how the texels of a texture are sampled