View source for Multitexture with GLSL

Many users want to have some form of multitexturing. They may want texture #1 and texture #2 to be multiplied together, or added together, or blended together based on some kind of factor like an alpha value.<br>
This shows GLSL code for doing blending between 2 texture based on a alpha value.<br>
Why would you use GLSL if it requires a GL 2.0 minimum?<br>
1. Because GL 2.0 has been available for a few years now<br>
2. Most everyone has a GL 2.0 capable video card in their system (Geforce FX and up, Radeon 9500 and up)<br>
3. The fixed function pipeline is eliminated from GPU for a long time now. It is better to just use shaders and to write modern code.<br>
<br>
If Texture0 is your 1st texture.<br>
If Texture1 is your 2nd texture.<br>
If Texture2 is your alpha mask source.<br>
The GLSL code for the FS would look like this
   uniform sampler2D Texture0;
   uniform sampler2D Texture1;
   uniform sampler2D Texture2;   //Mask
   varying vec2 TexCoord0;
   //-------------------
   void main()
   {  
      vec4 texel0, texel1, texel2, resultColor;
      //-------------------
      texel0 = texture2D(Texture0, TexCoord0);
      texel1 = texture2D(Texture1, TexCoord0);
      texel2 = texture2D(Texture2, TexCoord0);
      //-------------------
      resultColor = mix(texel0, texel1, texel2.a);
      gl_FragColor = resultColor;
   }

<br>
If Texture0 is your 1st texture. This is also the source of the alpha mask.<br>
If Texture1 is your 2nd texture.<br>
   uniform sampler2D Texture0;
   uniform sampler2D Texture1;
   varying vec2 TexCoord0;
   //-------------------
   void main()
   {  
      vec4 texel0, texel1, resultColor;
      //-------------------
      texel0 = texture2D(Texture0, TexCoord0);
      texel1 = texture2D(Texture1, TexCoord0);
      //-------------------
      resultColor = mix(texel0, texel1, texel0.a);
      gl_FragColor = resultColor;
   }

[[Category:OpenGL Shading Language]]