Uniform problem in Shader Designer


I couldn’t find any Typhoonlabs Shader Designer specific discussion forum, so I’m going to post this here for now.

My problem is: one of the uniforms, named SpecExp, does not work in my Blinn shader. I have added it to Uniform Variables panel (Id: 1, Type: float, Name: SpecExp, Values: 32.0) and it’s checked. When I run the shader, the model ends up being white as if SpecExp was zero, although it is NOT. Here’s my shader code:

uniform sampler2D TextureUnit0;
uniform float     SpecExp;

varying vec4 Cs;

varying vec4 V_eye;
varying vec4 L_eye;
varying vec4 N_eye;

void main(void)
  	vec3 V = normalize(vec3(V_eye));
  	vec3 L = normalize(vec3(L_eye));
  	vec3 N = normalize(vec3(N_eye));
  	vec4 Cd = texture2D(TextureUnit0, gl_TexCoord[0].xy);

  	float diffuse = clamp(dot(L, N), 0.0, 1.0);

  	vec3 H = normalize(L + V);
  	float specular = clamp(pow(dot(N, H), SpecExp), 0.0, 1.0);

  	gl_FragColor = Cd*0.5 + (Cd*diffuse)*0.5 + (Cs*specular);

If I change the SpecExp within pow() statement to a float value such as 32.0, it works without problems. I have Windows XP SP2, ATI Radeon 9700 with drivers installed.


Hello Arkion,
I’m the Shader Designer’s writter (next time mail directly to me instead of use this forums :slight_smile: ).
Your problem happens with all ATI Radeon cards when using the Shader Designer. I think that is caused by I bug in the ATI driver. Yesterday I’ve started a thread in this form related with this issue. I finally was able to reproduce the problem with a “minimal” application and I’ve posted it ( http://www.opengl.org/discussion_boards/cgi_directory/ultimatebb.cgi?ubb=get_topic;f=11;t=000736 )
in order to see if somebody could check that code and see if I’m making something wrong (I really doubth it). I already sent a bugreport to ATI with this sample application, so I’m waiting for the reply.

When I get confirmed that is a driver bug (or a bug in my code) I’ll build a new version that fixes it (if is my fault) and introduces some little improvements.

This topic was automatically closed 183 days after the last reply. New replies are no longer allowed.