gl_FrontLightProduct[i].specular not working?

OpenGL
1

I have made a Shader that has both specular lightning and multiple lights. But, I can’t get it to work properly.

gl_FrontLightProduct[i].diffuse and gl_FrontLightProduct[i].ambient work just great. But whenever I put in gl_FrontLightProduct[i].specular, my specular lighting quits working.

Any ideas on what is going on?

Frag shader:

 

#define MAX_LIGHTS 8
#define NUM_LIGHTS 1
varying vec3 lightVec[NUM_LIGHTS];
varying vec3 halfVec[NUM_LIGHTS];
uniform sampler2D colorMap;
uniform sampler2D normalMap;
uniform sampler2D specularMap;
uniform float shininess;

void main(void)
{
  vec2 uv = gl_TexCoord[0].st;
  vec4 base = texture2D(colorMap, gl_TexCoord[0].st);
  vec4 final_color = vec4(0.0, 0.0, 0.0, 0.0);
  vec3 bump =normalize(texture2D(normalMap, gl_TexCoord[1].st).xyz * 2.0 - 1.0);
  vec4 specularColor=texture2D(specularMap, gl_TexCoord[2].st);

  int i;
  for (i=0; i<NUM_LIGHTS; ++i)
  {
    //ambient
    vec4 vAmbient=gl_FrontLightProduct[i].ambient*base;
    final_color += vAmbient;

    //diffuse
    vec3 lVec = normalize(lightVec[i]);
    float diffuse = max(dot(lVec, bump), 0.0);
    vec4 vDiffuse =gl_FrontLightProduct[i].diffuse *diffuse * base;
    final_color += vDiffuse;

    //specular
    float specularModifier=max(dot(bump, normalize(halfVec[i])), 0.0);
    vec4 vSpecular= (specularColor *pow(specularModifier, shininess));
    //previous line SHOULD BE: vec4 vSpecular= gl_FrontLightProduct[i].specular *specularColor *pow(specularModifier, shininess);
    final_color += vSpecular;
  }
  gl_FragColor = clamp(final_color, 0.0, 1.0);
  gl_FragColor.a=base.a;
}
2

Make sure your light specular (gl_LightSource[i].specular) and material specular (gl_FrontMaterial.specular) are not black.

3

I am very sure that they are not black.

As my specular works (albiet a bit odd without the proper light), WITHOUT gl_LightSource[i].specular. So I know that material is good.

And I am setting the specular component of the light to be (1.0, 1.0, 1.0, 1.0), So I am sure it the light is not black.

Could it be my graphics card??

I havn’t had a chance to try it on anouther computer yet. I am using Python, and PyInstaller and Py2EXE don’t work with OpenGL very well.

4

You don’t use material specular color in the shader code (aside from the commented line), so how do you know it’s good?

5

right above the commented Line:

 vec4 vSpecular= (specularColor *pow(specularModifier, shininess));

and right before the start of the loop:


vec4 specularColor=texture2D(specularMap, gl_TexCoord[2].st);
6

That is not material specular… That is your custom specular map.


gl_FrontLightProduct[i].specular = gl_FrontMaterial.specular * gl_LightSource[i].specular

I repeat, check your material specular (gl_FrontMaterial.specular).

7

AH!!!

Figured it out!

Thanks.
That also let me figure out some other stuff as well…

8

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