question: void renderNormal ( ) { glEnable ( GL_DEPTH_TEST ) ; glUseProgram ( this . normalProgram ) ; glUniformMatrix4fv ( viewMatrixUniform , false , viewMatrix . get ( matrixBuffer ) ) ; glUniformMatrix4fv ( projMatrixUniform , false , projMatrix . get ( matrixBuffer ) ) ; glUniformMatrix3fv ( normalMatrixUniform , false , normalMatrix . get ( matrixBuffer ) ) ; glBindFramebufferEXT ( GL_FRAMEBUFFER_EXT , fbo ) ; glClear ( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ) ; glBindBuffer ( GL_ARRAY_BUFFER , this . cubeVbo ) ; glEnableVertexAttribArray ( 0 ) ; glVertexAttribPointer ( 0 , 3 , GL_FLOAT , false , 0 , 0L ) ; glEnableVertexAttribArray ( 1 ) ; glVertexAttribPointer ( 1 , 3 , GL_FLOAT , false , 0 , this . normalsOffset ) ; glDrawArrays ( GL_TRIANGLES , 0 , this . numVertices ) ; glDisableVertexAttribArray ( 0 ) ; glDisableVertexAttribArray ( 1 ) ; glBindBuffer ( GL_ARRAY_BUFFER , 0 ) ; glBindFramebufferEXT ( GL_FRAMEBUFFER_EXT , 0 ) ; glUseProgram ( 0 ) ; }
target:  Render the normals into a texture.