My openGL shaders will not link outside of eclipse? - windows

Question

So I am trying to build a simple spirograph generator for school and everything went fine while in eclipse CDT for windows 7. My program assigns a default shader to each spirograph generated (5 max). There are also 3 other shader programs the user can assign by choice to any spirograph. Inside eclipse it works exactly as it should, but when being ran outside eclipse the shaders fail to link. The program uses GLUT and GLEW and I have included the necessary .dll's in the executable's directory. I've been trying to fix this for a good 4 hours and have no idea what would cause a failure to link outside of eclipse that wouldn't fail all the time.
Im not going to include all of the shaders but here are the first 2 that fail to link and cause the application to terminate
#version 330
layout (location = 0) in vec4 vPosition;
uniform mat4 model;
uniform mat4 view;
uniform mat4 proj;
out vec4 color;
void main()
{
gl_Position = proj * view * model * vPosition;
color = vec4(
(4 - vPosition.z) * (4 - vPosition.z) / 16.0,
(2.0 - abs( 2.0 - vPosition.z )) / 2.0,
vPosition.z * vPosition.z / 16.0,
1.0
);
}
and fragment shader
#version 330
in vec4 color;
void main()
{
gl_FragColor = color;
}
and printlog
Vertex shader was successfully compiled to run on hardware.
Fragment shader was successfully compiled to run on hardware.
Fragment shader(s) failed to link, vertex shader(s) failed to link.
ERROR: error(#280) Not all shaders have valid object code
ERROR: error(#280) Not all shaders have valid object code
The InitShader() function that I use to compile and link the shaders has worked for the applications I have done in the past. The only thing I am doing different is I am using it to produce a few different shader programs and assign them to programs[] rather than just compile 1 and run it for the whole application.
program[0] = InitShader("shaders/vshader.glsl", "shaders/fshader.glsl");
program[1] = InitShader("shaders/vshader2.glsl", "shaders/fshader.glsl");
program[2] = InitShader("shaders/vshader3.glsl", "shaders/fshader.glsl");
program[3] = InitShader("shaders/vshaderw.glsl", "shaders/fshader.glsl");
But either way, here is the code for InitShader().
GLuint InitShader(const char* source, GLenum type)
{
GLuint shader = glCreateShader(type);
glShaderSource(shader, 1, (const GLchar**) &source, NULL );
glCompileShader(shader);
printLog( shader );
return shader;
}
GLuint InitShader(const char* vfile, const char *ffile) {
GLuint program = glCreateProgram();
GLuint shader;
// stringify and attach vshader
std::ifstream vertstream(vfile);
std::string vert((std::istreambuf_iterator<char>(vertstream)), std::istreambuf_iterator<char>());
shader = InitShader(vert.c_str(), GL_VERTEX_SHADER);
glAttachShader( program, shader );
// stringify and attach fshader
std::ifstream fragstream(ffile);
std::string frag((std::istreambuf_iterator<char>(fragstream)), std::istreambuf_iterator<char>());
shader = InitShader(frag.c_str(), GL_FRAGMENT_SHADER);
glAttachShader( program, shader );
// link program
glLinkProgram(program);
printLog(program);
// link and error check
GLint linked;
glGetProgramiv( program, GL_LINK_STATUS, &linked );
if ( !linked ) {
fprintf(stderr, "Shaders failed to link!\n");
exit( EXIT_FAILURE );
}
// use program object
glUseProgram(program);
return program;
}
Its 4am here so my grey cells are about spent haha. And fyi its not really homework help, the executable is not required to run outside of eclipse for the class, I just want to know how to create stand alone programs for myself.

Answer 1

The cause of your problem lies here:
program[0] = InitShader("shaders/vshader.glsl", "shaders/fshader.glsl");
The paths to the shader source files are relative. Chances are, that Eclipse runs your program from a different working directory (probably your project root) than what's the working directory when executing the program directly.
Solution: Either
make sure the working directory on program startup matches the relative paths used internally (very unreliable)
use absolute paths within the program (very unflexible)
or, what I suggest
determine the location of the shader files at runtime (command line option, location of the executable binary, etc) and adjust the paths accordingly at runtime.