opengl - GLSL - Weird syntax error "<" -

i'm trying use shader keeps telling me error on both fragment , vertex shader:

error(#132) syntax error: "<" parse error 

vertex shader

varying vec4 diffuse; varying vec4 ambient; varying vec3 normal; varying vec3 halfvector;   void main() {     normal = normalize(gl_normalmatrix * gl_normal);       halfvector = gl_lightsource[0].halfvector.xyz;       diffuse = gl_frontmaterial.diffuse * gl_lightsource[0].diffuse;     ambient = gl_frontmaterial.ambient * gl_lightsource[0].ambient;     ambient += gl_lightmodel.ambient * gl_frontmaterial.ambient;      gl_position = ftransform();   } 

fragment shader

varying vec4 diffuse,ambient; varying vec3 normal,halfvector;   void main() {     vec3 n,halfv,lightdir;     float ndotl,ndothv;       lightdir = vec3(gl_lightsource[0].position);       vec4 color = ambient;       n = normalize(normal);       ndotl = max(dot(n,lightdir),0.0);     if (ndotl > 0.0) {         color += diffuse * ndotl;         halfv = normalize(halfvector);         ndothv = max(dot(n,halfv),0.0);         color += gl_frontmaterial.specular *                 gl_lightsource[0].specular *                 pow(ndothv, gl_frontmaterial.shininess);     }       gl_fragcolor = color;   }  

code read shaders:

bool shader::load(string vertex , string fragment) {     // these hold shader's text file data     string vshader, fshader;      // make sure user passed in vertex , fragment shader file     if(!vertex.length() || !fragment.length()) return false;      // if of our shader pointers set, let's free them first.     if(vertexshader || fragmentshader || programobject) release();      // here pointer our vertex , fragment shaders     vertexshader = glcreateshader(gl_vertex_shader);     fragmentshader = glcreateshader(gl_fragment_shader);      // load shaders respective files , store in string.     vshader = loadtextfile(vertex.c_str());     fshader = loadtextfile(fragment.c_str());      if(vshader == "" || fshader == "") return false;      // quick switch can double pointer below     const char *vvshader = vshader.c_str();     const char *ffshader = fshader.c_str();      // assigns shader text file each shader pointer     glshadersource(vertexshader, 1, &vvshader, null);     glshadersource(fragmentshader, 1, &ffshader, null);      // compile shader's code     glcompileshader(vertexshader);     glcompileshader(fragmentshader);      printinfolog(vertexshader);     printinfolog(fragmentshader);      // next create program object represent our shaders     programobject = glcreateprogram();      // attach each shader loaded our program object     glattachshader(programobject, vertexshader);     glattachshader(programobject, fragmentshader);      // our last init function link our program object opengl     gllinkprogram(programobject);      printinfolog(programobject);      // now, let's turn off our current shader.     gluseprogram(0);      return true;  }   string shader::loadtextfile(string file) {     // open file passed in     ifstream fin(file.c_str());      // make sure opened file correctly     if(!fin) return "";      string line = "";     string text = "";      // go through , store each line in text file within "string" object     while(getline(fin, line))     {         text = text + "\n" + line;     }      // close our file     fin.close();      // return text file's data     return text; } 

however, if try shader works fine! don't know why.

your error , lack of < token in shader sources suggests glshadersource reading trailing garbage @ end of strings.

this sounds subtle problem known seasoned developers can stump newbies. glshadersource either expects 0 terminated strings , null pointer length array or you're passing array lengths strings don't need 0 terminated. technically std::string::c_str should give access 0 terminated string, seems in case doesn't.

anyway simple solution provide length array, glshadersource doesn't read trailing garbage:

// quick switch can double pointer below const char *vvshader = vshader.c_str(); const char *ffshader = fshader.c_str(); const glint lenvshader = vshader.length(); const glint lenfshader = fshader.length();  // assigns shader text file each shader pointer glshadersource(vertexshader, 1, &vvshader, &lenvshader); glshadersource(fragmentshader, 1, &ffshader, &lenfshader);