title: Multitexture GL_TEXTURE1 issue on WebGL
body: <p>I am learning to use multitexture on WebGL. I have the following shader code snippets:</p>
  
  <pre><code>uniform int flag;
  
  uniform sampler2D texture0;
  uniform sampler2D texture1;
  
  varying vec2 v_texCoord;
  
  void main()
  {
      vec2 texCoord = vec2(v_texCoord.s, 1.0 - v_texCoord.t);
  
      vec4 texel0 = texture2D(texture0, texCoord);
      vec4 texel1 = texture2D(texture1, texCoord);
  
      if (1 == flag) 
      {
          gl_FragColor = texel1;
  
      } else
      {
          gl_FragColor = texel0;
      }
  }
  </code></pre>
  
  <p>Also, my JavaScript code snippets:</p>
  
  <pre><code>gl.uniform1i(gl.getUniformLocation(gl.program, "flag"), 1);
  gl.uniform1i(gl.getUniformLocation(gl.program, "texture0"), 0);     // Texture Unit 0
  gl.uniform1i(gl.getUniformLocation(gl.program, "texture1"), 1);     // Texture Unit 1
  // Activate 2 textures
  gl.enable(gl.TEXTURE_2D);
  
  gl.activeTexture(gl.GL_TEXTURE0);    
  gl.bindTexture(gl.TEXTURE_2D, photoTexture0);
  
  gl.activeTexture(gl.GL_TEXTURE1);    
  gl.bindTexture(gl.TEXTURE_2D, photoTexture1);
  </code></pre>
  
  <p>The photoTexture1 (texture1) displays black only on the screen. I can display the photoTexture0 (texture0) correctly. It seems that photoTexture1 (texture1) is not visible in the shader.</p>
  
  <p>Since the above code does not work and I am new on this, I am wondering if I did something wrong and/or I misunderstand the concept how multitexture works.</p>
  
  <p>Any help is appreciated. Thanks in advance for your help.</p>
  
  <p>NOTE: Cross post on <a href="http://www.khronos.org/message_boards/viewtopic.php?f=43&amp;t=3357&amp;p=8858#p8858" rel="nofollow">http://www.khronos.org/message_boards/viewtopic.php?f=43&amp;t=3357&amp;p=8858#p8858</a> </p>