Derelict-GL3 Error

[Kevin via Digitalmars-d]

On Tuesday, 10 January 2017 at 04:34:24 UTC, Mike Parker wrote:
> On Tuesday, 10 January 2017 at 01:43:50 UTC, Kevin wrote:
>> Using Archlinux, Derelict-gl3 1.0.18
>> check format (GLuint, Glenum, Glint*)
>>
>> // this does not work
>> glGetShaderiv(program, GL_LINK_STATUS, &success);
>> writeln("GL_ERROR: ", glGetError());
>>
>> Give me error 1282
>>
>> // this one works fine.
>> glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
>
> This has nothing to do with Derelict. It's an error in your use 
> of OpenGL, so you need to look up the OpenGL error code 1282 
> and figure out what it means.
>
> Since I'm here, I'll save you some time. 1282 is 
> GL_INVALID_OPERATION. However, just because you called it 
> immediately after glGetShaderiv *does not mean* that function 
> caused the error. The error code may have been set any time 
> before that, by any of the functions you called. Then, when you 
> call glGetError, the error code is reset to 0, so your next 
> call to glGetError shows no error.
>
> Here's some psuedocode to illustrate:
>
> // OpenGL's internal error code
> errCode = 0;
>
> // In your code:
> glSomething(); // no error
> glSomethingElse(); // no error
> glAnotherThing();  // Oops! An error - errCode now is set to 
> 1282
> glThisThing();  // No error, but the state is now messed up
> glThatThing();  // No error
> err = glGetError();  // This returns 1282, as set by 
> glAnotherThing above
>
>
> What you need to do is debug your OpenGL code. The simplest way 
> to do that is to insert glGetError at different points, 
> recompile, and run it again. This will help you narrow things 
> down to the function that actually caused the error.
>
> And for future reference, please go to opengl.org or the OpenGL 
> forums at gamedev.net for help with OpenGL.

Thanks for info. I already did glGetError() above and below.
and it only from that code. At first I thought i put the wrong 
type. I set success to 1 and let code go through and shader work 
fine. The glGetShaderiv(program, GL_LINK_STATUS, &success) check 
does not work. If you still think it opengl problem I will take 
it there or maybe i made a simple mistake I can't see.

full code
import std.string : toStringz;
import std.stdio;
import std.file;

import derelict.opengl3.gl;

struct Shader {
   private GLuint program;

   @disable this(this);

   ~this() {
     glDeleteProgram(program);
   }

   void use() {
     glUseProgram(program);
   }

   bool create(string vertexName, string fragmentName, string 
geometryName=null) {
     char[512] infoLog;
     program = 0;
     GLuint vertexShader = shaderFile(vertexName, 
GL_VERTEX_SHADER);
     GLuint fragmentShader = shaderFile(fragmentName, 
GL_FRAGMENT_SHADER);
     GLuint geometryShader = 0;
     GLint success = 1;

     if(geometryName !is null)
       geometryShader = shaderFile(geometryName, 
GL_GEOMETRY_SHADER);

     if(vertexShader == 0) {
       writeln("Vertex is null");
       return false;
     }

     if(fragmentShader == 0) {
       writeln("Fragment is null");
       glDeleteShader(vertexShader);
       return false;
     }

     if(geometryName !is null) {
       if(geometryShader == 0) {
         writeln("Geometry is null");
         glDeleteShader(vertexShader);
         glDeleteShader(fragmentShader);
         return false;
       }
     }

     // create program
     program = glCreateProgram();
     glAttachShader(program, vertexShader);
     glAttachShader(program, fragmentShader);
     if(geometryName !is null)
       glAttachShader(program, geometryShader);

     glLinkProgram(program);
     writeln("Before GL_ERROR: ", glGetError());

     // this does not work
     glGetShaderiv(program, GL_LINK_STATUS, &success);
     writeln("After GL_ERROR: ", glGetError());
     if(!success) {
       writeln("GL_ERROR: ", glGetError());
       glGetShaderInfoLog(program, 512, null, infoLog.ptr);
       writeln("ERROR::Shader program linking failed");
       writeln(infoLog);
     }

     glDeleteShader(vertexShader);
     glDeleteShader(fragmentShader);
     if(geometryName !is null)
       glDeleteShader(geometryShader);

     return cast(bool) success;
   }

   private GLuint shaderFile(string sourceName, GLenum flag) {
     string fileData;
     GLchar* source;
     GLint success;
     GLchar[512] infoLog;
     GLuint shader = 0;

     if(exists(sourceName) != 0)
       fileData = cast(string) read(sourceName);
     else {
       writeln("ERROR: File doesn't exist");
       return 0;
     }

     source = cast(GLchar*) (toStringz(fileData));
     shader = glCreateShader(flag);
		glShaderSource(shader, 1, &source, null);
		glCompileShader(shader);

     // this one work fine
     glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
     writeln("sh .. GL_ERROR: ", glGetError());
		if(!success)
		{
			glGetShaderInfoLog(shader, 512, null, infoLog.ptr);
       if(flag == GL_VERTEX_SHADER)
         writeln("ERROR::Shader vertex compiltion failed ");
       else if(flag == GL_FRAGMENT_SHADER)
         writeln("ERROR::Shader fragment compiltion failed");
       else if(flag == GL_GEOMETRY_SHADER)
         writeln("ERROR::Shader geometry compiltion failed");

       writeln(infoLog);
		}

     return shader;
   }
}