How to debug GLSL Fragment shader (Program Linking error after code change)

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我寻月下人不归 2021-01-26 10:43

(original Title) Please help me debug my glsl lighting shader so that it will compile! This is my first time debugging glsl

Hello I am VERY new to openg

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情歌与酒 (楼主)

2021-01-26 10:59

Errors log of yours are not good

it is some linking log from the tool you are using
not the OpenGL compilation log !!!

I put your fragment shader into OpenGL and this is the real compilation log (nVidia used):

[Fragment]
Compiler error
0(94) : error C1009: "ambient" is not member of struct "DirLight"
0(95) : error C1009: "diffuse" is not member of struct "DirLight"
0(96) : error C1009: "specular" is not member of struct "DirLight"

[Program]
Linker error
Fragment info
-------------
0(94) : error C1009: "ambient" is not member of struct "DirLight"
0(95) : error C1009: "diffuse" is not member of struct "DirLight"
0(96) : error C1009: "specular" is not member of struct "DirLight"

you should use glGetShaderInfoLog for every shader/program object you use in OpenGL
I use something like this

It makes sense:

vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
{
    vec3 lightDir = normalize(-light.direction);
    // Diffuse shading
    float diff = max(dot(normal, lightDir), 0.0);
    // Specular shading
    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    // Combine results
    vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, TexCoords));
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    return (diffuse + specular);
}

After the // Combine results you are accessing struct fields that are not defined in:

struct DirLight {
    vec3 direction;
    vec3 color;
    float strength;
};

[edit1] in C++ I use this class of mine for GLSL:

//------------------------------------------------------------------------------
//--- GLSL program class -------------------------------------------------------
//------------------------------------------------------------------------------
class GLSLprogram       // GLSL program class
    {
public:
    AnsiString log;
    int prog_id,    // whole program
        tesc_id,    // tessellation control
        tese_id,    // tessellation evaluation
        geom_id,    // geometry
        vert_id,    // vertex
        frag_id;    // fragment

    GLSLprogram();
    GLSLprogram(GLSLprogram& a);
    ~GLSLprogram();
    GLSLprogram* operator = (const GLSLprogram *a);
    //GLSLprogram* operator = (const GLSLprogram &a);
    void bind();
    void unbind();

    void set_source_text(AnsiString tesc,AnsiString tese,AnsiString geom,AnsiString vert,AnsiString frag);  // set source texts
    void set_source_file(AnsiString tesc,AnsiString tese,AnsiString geom,AnsiString vert,AnsiString frag);  // load and set source files

    void set1f   (AnsiString name,GLfloat x);
    void set2f   (AnsiString name,GLfloat x, GLfloat y);
    void set3f   (AnsiString name,GLfloat x, GLfloat y, GLfloat z);
    void set4f   (AnsiString name,GLfloat x, GLfloat y, GLfloat z, GLfloat w);
    void set1i   (AnsiString name,GLint x);
    void set2i   (AnsiString name,GLint x, GLint y);
    void set3i   (AnsiString name,GLint x, GLint y, GLint z);
    void set4i   (AnsiString name,GLint x, GLint y, GLint z, GLint w);
    void set1fv  (AnsiString name,GLfloat *p);
    void set2fv  (AnsiString name,GLfloat *p);
    void set3fv  (AnsiString name,GLfloat *p);
    void set4fv  (AnsiString name,GLfloat *p);
    void set1iv  (AnsiString name,GLint *p);
    void set2iv  (AnsiString name,GLint *p);
    void set3iv  (AnsiString name,GLint *p);
    void set4iv  (AnsiString name,GLint *p);
    void set2x2fv(AnsiString name,GLfloat *p);
    void set3x3fv(AnsiString name,GLfloat *p);
    void set4x4fv(AnsiString name,GLfloat *p);

    void get1f   (AnsiString name,GLfloat &x);
    void get2f   (AnsiString name,GLfloat &x, GLfloat &y);
    void get3f   (AnsiString name,GLfloat &x, GLfloat &y, GLfloat &z);
    void get4f   (AnsiString name,GLfloat &x, GLfloat &y, GLfloat &z, GLfloat &w);
    void get1i   (AnsiString name,GLint &x);
    void get2i   (AnsiString name,GLint &x, GLint &y);
    void get3i   (AnsiString name,GLint &x, GLint &y, GLint &z);
    void get4i   (AnsiString name,GLint &x, GLint &y, GLint &z, GLint &w);
    void get1fv  (AnsiString name,GLfloat *p);
    void get2fv  (AnsiString name,GLfloat *p);
    void get3fv  (AnsiString name,GLfloat *p);
    void get4fv  (AnsiString name,GLfloat *p);
    void get1iv  (AnsiString name,GLint *p);
    void get2iv  (AnsiString name,GLint *p);
    void get3iv  (AnsiString name,GLint *p);
    void get4iv  (AnsiString name,GLint *p);
    void get2x2fv(AnsiString name,GLfloat *p);
    void get3x3fv(AnsiString name,GLfloat *p);
    void get4x4fv(AnsiString name,GLfloat *p);
    };
//------------------------------------------------------------------------------
GLSLprogram::GLSLprogram()
    {
    prog_id=0;
    tesc_id=0;
    tese_id=0;
    geom_id=0;
    vert_id=0;
    frag_id=0;
    }
//------------------------------------------------------------------------------
GLSLprogram::~GLSLprogram()
    {
    if (glDetachShader==NULL) return;
    if (glDeleteShader==NULL) return;
    unbind();
    if (tesc_id>0) { glDetachShader(prog_id,tesc_id); glDeleteShader(tesc_id); }
    if (tese_id>0) { glDetachShader(prog_id,tese_id); glDeleteShader(tese_id); }
    if (geom_id>0) { glDetachShader(prog_id,geom_id); glDeleteShader(geom_id); }
    if (vert_id>0) { glDetachShader(prog_id,vert_id); glDeleteShader(vert_id); }
    if (frag_id>0) { glDetachShader(prog_id,frag_id); glDeleteShader(frag_id); }
    if (prog_id>0) {                                  glDeleteShader(prog_id); }
    log="";
    }
//------------------------------------------------------------------------------
void GLSLprogram::bind()
    {
    if (glUseProgram==NULL) return;
    glUseProgram(prog_id);
    }
//------------------------------------------------------------------------------
void GLSLprogram::unbind()
    {
    if (glUseProgram==NULL) return;
    glUseProgram(0);
    }
//------------------------------------------------------------------------------
void GLSLprogram::set_source_text(AnsiString tesc,AnsiString tese,AnsiString geom,AnsiString vert,AnsiString frag)
    {
    if (glCreateProgram==NULL) return;
    if (glShaderSource==NULL) return;
    if (glCompileShader==NULL) return;
    if (glAttachShader==NULL) return;
    if (glGetShaderiv==NULL) return;
    if (glGetShaderInfoLog==NULL) return;
    if (glLinkProgram==NULL) return;

    if (glGetProgramiv==NULL) return;
    if (glGetProgramInfoLog==NULL) return;
    if (glReleaseShaderCompiler==NULL) return;

    const int _size=1024;
    char dat[_size];
    GLint status,siz=0,i;
    const char * TC = tesc.c_str();
    const char * TE = tese.c_str();
    const char * GS = geom.c_str();
    const char * VS = vert.c_str();
    const char * FS = frag.c_str();
    log="";

    if (prog_id<=0) prog_id=glCreateProgram();

    if (tesc_id<=0) tesc_id=glCreateShader(GL_TESS_CONTROL_SHADER);
    else glDetachShader(prog_id,tesc_id);
    if (tesc!="")
        {
        glShaderSource(tesc_id, 1, &TC,NULL);
        glCompileShader(tesc_id);
        glAttachShader(prog_id,tesc_id);
        glGetShaderiv(tesc_id,GL_COMPILE_STATUS,&status);
        log+="[Tessellation control]\n";
        if (status) log+="OK\n"; else log+="Compiler error\n";
        glGetShaderInfoLog(tesc_id,_size,&siz,dat);
        for (i=0;i




AnsiString is just VCL string class (self relocable string class) can use anything else like char[] or char* instead but you need to handle operators of coarse...
AnsiString().c_str() returns char* compatible pointer to stored string


usage:

// [variables]
GLSLprogram   shader;
// [init]
shader.set_source_text("","","","your vertex shader source text","your fragment shader source text");
shader.log; // contains the compile/link log ...
shader.prog_id; // contains the OpenGL id for your shader object


// [render]
shader.bind();
// here render
shader.unbind();


[edit2] And also I forget to add:

AnsiString load(AnsiString file)
    {
    int i,hnd,siz;
    char *dat=NULL;
    hnd=FileOpen(file,fmOpenRead);
    if (hnd<0) return "";
    siz=FileSeek(hnd,0,2);
        FileSeek(hnd,0,0);
    if (siz==0) { FileClose(hnd); return ""; }
    dat=new char[siz+1];
    if (dat==NULL) { FileClose(hnd); return ""; }
    FileRead(hnd,dat,siz);
    FileClose(hnd);
    AnsiString s=""; for (i=0;i