OpenGL GLSL shaders on Mac does not compile

Question

When I try to compile GLSL shaders for my application on Mac, it fails with a version conflict error of the shader:

Error compiling vertex shader:
ERROR: 0:1: '' :  version '130' is not supported

Error compiling shader:
ERROR: 0:1: '' :  version '130' is not supported

The shaders are as such:

Vertex shader:

#version 130

in vec2 in_vPos;
in vec2 in_vTexCoord;

out vec2 s_vTexCoord;

void main()
{
    gl_Position = vec4(in_vPos, 0, 1);
    s_vTexCoord = (in_vTexCoord + vec2(1, 1)) / 2;
}

Fragment shader:

#version 130

in vec2 s_vTexCoord;

out vec4 s_colOut;

uniform sampler2DRect s_texSampler;
uniform vec4 s_colBlend;

void main()
{
    vec4 pixel = texture(s_texSampler, s_vTexCoord * textureSize(s_texSampler));
    s_colOut = s_colBlend * pixel;
}

This is how I initialize my SDL renderer and Glew:

  ren_pRenderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);

  SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
  SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
  glEnable(GL_MULTISAMPLE);

  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE | SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG);

  SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "1");

  static bool _bInitializedGlew = false;
  if(!_bInitializedGlew) {
    glewExperimental = GL_TRUE;
    GLenum err = glewInit();
    if(err != GLEW_OK) {
      printf("Glew initialization error: %d\n", err);
    }
    _bInitializedGlew = true;
  }

And this is how I compile the shaders:

unsigned int CShader::CompileShader(const char* str, int type, bool &bSuccess)
{
    // create a new shader
    GLuint iShader = glCreateShader(type);
    const GLchar* aSourceVertex[] = { str };
    glShaderSource(iShader, 1, aSourceVertex, NULL);
    glCompileShader(iShader);

    // check if compiling went okay
    GLint bShaderCompiled = GL_FALSE;
    glGetShaderiv(iShader, GL_COMPILE_STATUS, &bShaderCompiled);
    if(bShaderCompiled != GL_TRUE) {
        // it did not.
        printf("Error compiling %sshader:\n", (type == GL_VERTEX_SHADER ? "vertex " : ""));
        int iLogLength = 0;
        int iMaxLength = 0;
        glGetShaderiv(iShader, GL_INFO_LOG_LENGTH, &iMaxLength);
        char* buffer = new char[iMaxLength];
        glGetShaderInfoLog(iShader, iMaxLength, &iLogLength, buffer);
        if(iLogLength > 0) {
            printf("%s\n", buffer);
        }
        delete[] buffer;

        // report it back
        bSuccess = false;
        // and delete the shader
        glDeleteShader(iShader);
    } else {
        // it worked!
        bSuccess = true;
    }

    // return shader
    return iShader;
}

I looked around for answers before and couldn't find a conclusive Stackoverflow answer that could help me, though it did point me in the right direction with SDL_GL_SetAttribute for setting the GL version and core profile. So in above code, I set it to 3.1 Core, which, according to Wikipedia, is #version 140, but even if I use that, I get the same error:

Error compiling vertex shader:
ERROR: 0:1: '' :  version '140' is not supported

Error compiling shader:
ERROR: 0:1: '' :  version '140' is not supported

Edit: I changed the version in attributes to 3.2 Core + Forward Compat, and now using #version 150 I get the same issue, saying 150 is not supported.

When I print the result of glGetString(GL_SHADING_LANGUAGE_VERSION) I get 1.20.

Even if I explicitly create the context after creating the SDL window, it still reports 1.20:

win_pWindow = SDL_CreateWindow(strTitle, iX, iY, width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN | ulFlags);
win_pContext = SDL_GL_CreateContext(win_pWindow);
printf("GLSL version: %s\n", glGetString(GL_SHADING_LANGUAGE_VERSION));

Brawley

Answer 1

Hmm, how about that error message:

Error compiling vertex shader:
ERROR: 0:1: '' :  version '130' is not supported

That's exactly what your problem is. GLSL version 1.30 relates to OpenGL-3.0; since there were not core/compatibility profiles in that version, yet, MacOS X doesn't support it.

When it comes to modern OpenGL MacOS X only supports core profile. So you need a core profile context and have to write your shaders with a core profile version. OpenGL-3 core profiles have been introduced only with OpenGL-3.2, the corresponding GLSL version is 1.50. So you have to write #version 150 there.

Declinature

As a minor side note: all core profile versions to date are required to support GLSL back to 1.40 for some reason, so bumping it to #version 140 would be enough. – Allomorphism

Answer 2

You are not creating the context version you think you are creating:

SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE | SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG)

is just invalid, the SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG does not belong into the SDL_GL_CONTEXT_PROFILE_MASK flags, but into the SDL_GL_CONTEXT_FLAGS.

Actually, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG has the same value as SDL_GL_CONTEXT_PROFILE_COMPATIBILITY, so you did request both a core and compatibility profile at the same time. I suspect that you got a legacy context with that, which is limited to GL <=2.1 on OSX.

Allomorphism

Answer 3

• I have heard that using SDL_Renderer bumps down the OpenGL version to a compatibility profile/a version of OpenGL that doesn't use core profile (so, a OpenGL version less than 3.2)

• Make sure you make both the window and context after setting the version etc with SDL_GLSetAttribute. So your code should look like:

  SDL_GLSetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  SDL_GLSetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
  SDL_GLSetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
  
  //create window
  
  //create context
  

This is how I managed to get a 3.3 context on my mac. From your code, I can't see if you created both the context and window after the attributes.

Gawen

Really though OP shouldn't be trying to inter-op SDL_Renderer and OpenGL. There's no provision in the API to save/restore the SDL_Renderer state, if it's even using the OpenGL backend at all. – Adrienneadrift

Answer 4

I am still new to OpenGL and GLFW, and I'm not exactly sure what the issue is, but having this same problem on macOS but putting the following code block at this position fixed the problems.

glfwInit();

glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
 glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

GLFWwindow *window = glfwCreateWindow( ... );

Pierpont