Yes, so I try to draw the axis. However, I encounter some problems and I think it is becasue of the mistake in shader script.

I use 2 shader scripts to generate the model (one for color and one for texture). It is nice if I only draw the color mode.

```
<script id="shader-fs" type="x-shader/x-fragment">
#ifdef GL_ES
precision highp float;
#endif
varying vec4 vTransformedNormal;
varying vec4 vPosition;
uniform vec3 uAmbientColor;
uniform vec3 uPointLightingLocation;
uniform vec3 uPointLightingSpecularColor;
uniform vec3 uPointLightingDiffuseColor;
varying vec4 vColor;
varying vec3 vLightWeighting;
void main(void) {
vec3 lightWeighting;
vec3 lightDirection = normalize(uPointLightingLocation - vPosition.xyz);
vec3 normal = normalize(vTransformedNormal.xyz);
float specularLightWeighting = 0.0;
float shininess = 32.0;
if (shininess < 255.0) {
vec3 eyeDirection = normalize(-vPosition.xyz);
vec3 reflectionDirection = reflect(-lightDirection, normal);
specularLightWeighting = pow(max(dot(reflectionDirection, eyeDirection), 0.0), shininess);
}
float diffuseLightWeighting = max(dot(normal, lightDirection), 0.0);
lightWeighting = uAmbientColor + uPointLightingSpecularColor * specularLightWeighting + uPointLightingDiffuseColor * diffuseLightWeighting;
gl_FragColor = vec4(vColor.rgb * lightWeighting, vColor.a);
}
</script>
<script id="shader-vs" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;
attribute vec3 aVertexNormal;
attribute vec4 aVertexColor;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;
varying vec4 vColor;
varying vec4 vTransformedNormal;
varying vec4 vPosition;
void main(void) {
vPosition = uMVMatrix * vec4(aVertexPosition, 1.0);
gl_Position = uPMatrix * vPosition;
vColor = aVertexColor;
vTransformedNormal = uNMatrix * vec4(aVertexNormal, 1.0);
}
</script>
<script id="shader-fs-texture" type="x-shader/x-fragment">
#ifdef GL_ES
precision highp float;
#endif
varying vec2 vTextureCoord;
uniform sampler2D uSampler;
void main(void) {
gl_FragColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
}
</script>
<script id="shader-vs-texture" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;
attribute vec2 aTextureCoord;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
varying vec2 vTextureCoord;
void main(void) {
gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
vTextureCoord = aTextureCoord;
}
</script>
```

When I draw the line (x, y, z axis) and texture (x, y, z letter), it draws nothing. When I remove the lighting effect and use the shader scripts without lighting effect, it draws the model and axis correctly.

```
gl.uniform3f(shaderProgram.ambientColorUniform, parseFloat(0.4), parseFloat(0.4), parseFloat(0.4));
gl.uniform3f(shaderProgram.pointLightingLocationUniform, parseFloat(10), parseFloat(-10), parseFloat(10));
gl.uniform3f(shaderProgram.pointLightingSpecularColorUniform, 1, 1, 1);
gl.uniform3f(shaderProgram.pointLightingDiffuseColorUniform, parseFloat(1), parseFloat(1), parseFloat(1));
mvPushMatrix();
gl.useProgram(shaderProgram);
drawAxisLine(gl, axis);
gl.useProgram(shaderProgramTexture);
drawAxisLetter(gl, axis);
```

Is there anything wrong in my shader script or other place? Can you help me to solve it?