GLSL语法问题:意外的new_identifier

Question

我刚刚开始学习OpenGL，并且正在关注本教程。我很难编译教程使用的GLSL文件。

最初，当我尝试编译它们时，编译器说MESA不支持GLSL版本330，因此我将#version 330 core更改为#version 130。现在，当我运行它时，它给了我以下错误：

3.0 Mesa 10.0.20Compiling shader : SimpleVertexShader.vertexshader
0:3(1): error: syntax error, unexpected NEW_IDENTIFIER
Compiling shader : SimpleFragmentShader.fragmentshader
Linking program
error: linking with uncompiled shader

我已经在Google上搜索过，找不到任何有这个问题的人。无论如何，这是所有有问题的文件：

simplevertexshader.vertexshader：

#version 130
layout(location = 0) in vec3 vertexPosition_modelspace;
void main(){
    gl_Position.xyz = vertexPosition_modelspace;
    gl_Position.w = 1.0;
}

SimpleFragmentShader.FragmentShader：

#version 130
out vec3 color;
void main() {
    color = vec3(1,0,0);
}

loadShader.cpp：

#include <stdio.h>
#include <string>
#include <vector>
#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
#include <stdlib.h>
#include <string.h>
#include <GL/glew.h>
GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path){
    // Create the shaders
    GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
    GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);
    // Read the Vertex Shader code from the file
    std::string VertexShaderCode;
    std::ifstream VertexShaderStream(vertex_file_path, std::ios::in);
    if(VertexShaderStream.is_open())
    {
        std::string Line = "";
        while(getline(VertexShaderStream, Line))
            VertexShaderCode += "n" + Line;
        VertexShaderStream.close();
    }
    // Read the Fragment Shader code from the file
    std::string FragmentShaderCode;
    std::ifstream FragmentShaderStream(fragment_file_path, std::ios::in);
    if(FragmentShaderStream.is_open()){
        std::string Line = "";
        while(getline(FragmentShaderStream, Line))
            FragmentShaderCode += "n" + Line;
        FragmentShaderStream.close();
    }
    GLint Result = GL_FALSE;
    int InfoLogLength;
    // Compile Vertex Shader
    printf("Compiling shader : %sn", vertex_file_path);
    char const * VertexSourcePointer = VertexShaderCode.c_str();
    glShaderSource(VertexShaderID, 1, &VertexSourcePointer , NULL);
    glCompileShader(VertexShaderID);
    // Check Vertex Shader
    glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
    glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
    std::vector<char> VertexShaderErrorMessage(InfoLogLength);
    glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
    fprintf(stdout, "%sn", &VertexShaderErrorMessage[0]);
    // Compile Fragment Shader
    printf("Compiling shader : %sn", fragment_file_path);
    char const * FragmentSourcePointer = FragmentShaderCode.c_str();
    glShaderSource(FragmentShaderID, 1, &FragmentSourcePointer , NULL);
    glCompileShader(FragmentShaderID);
    // Check Fragment Shader
    glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
    glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
    std::vector<char> FragmentShaderErrorMessage(InfoLogLength);
    glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
    fprintf(stdout, "%sn", &FragmentShaderErrorMessage[0]);
    // Link the program
    fprintf(stdout, "Linking programn");
    GLuint ProgramID = glCreateProgram();
    glAttachShader(ProgramID, VertexShaderID);
    glAttachShader(ProgramID, FragmentShaderID);
    glLinkProgram(ProgramID);
    // Check the program
    glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result);
    glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
    std::vector<char> ProgramErrorMessage( max(InfoLogLength, int(1)) );
    glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]);
    fprintf(stdout, "%sn", &ProgramErrorMessage[0]);
    glDeleteShader(VertexShaderID);
    glDeleteShader(FragmentShaderID);
    return ProgramID;
}

main.cpp：

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <GL/glew.h>
//#define GLFW_DLL // maybe some glu problems - look up
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path);
int main()
{
    GLFWwindow * window;
    if (!glfwInit()) {
        std::cout << "Failed to initiate GLFWn";
        return -1;
    }
    glfwWindowHint(GLFW_SAMPLES, 4); //4x antialiasing
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); //version 3
    //open a window and create context
    window=glfwCreateWindow(1024,768,"Lerning", glfwGetPrimaryMonitor(), NULL);
    if (!window) {
        std::cout << "Failed to open windown";
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    std::cout << glGetString(GL_VERSION);
    // initialize GLEW
    glewExperimental=GL_TRUE; //needed
    GLenum err = glewInit();
    std::cout << err;
    if (err != GLEW_OK) {
        std::cout << "Failed to initializen" << glewGetErrorString(err);
        return -1;
    }
    GLuint VertexArrayID;
    glGenVertexArrays(1, &VertexArrayID);
    glBindVertexArray(VertexArrayID);
    static const GLfloat g_vertex_buffer_data[] = {
        -1.0f, -1.0f, 0.0f,
        1.0f, 1.0f, 0.0f,
        0.0f, 1.0f, 0.0f,
    };
    GLuint vertexbuffer;
    glGenBuffers(1, &vertexbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data),
            g_vertex_buffer_data, GL_STATIC_DRAW);
    GLuint programID = LoadShaders("SimpleVertexShader.vertexshader",
            "SimpleFragmentShader.fragmentshader");
    while (!glfwWindowShouldClose(window)) {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glUseProgram(programID);
        glEnableVertexAttribArray(0);
        glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
        glVertexAttribPointer(
                0,
                3,
                GL_FLOAT,
                GL_FALSE,
                0,
                (void*)0
        );
        glDrawArrays(GL_TRIANGLES, 0, 3);
        glDisableVertexAttribArray(0);
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
    glfwTerminate();
    return 0;
}

Answer 1

layout(location = 0)在GLSL 1.30中无效。布局预选赛在GLSL 1.40中引入。在链接着着色器之前，您需要在C 代码中手动绑定该顶点属性位置。

// Check Fragment Shader
glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
std::vector<char> FragmentShaderErrorMessage(InfoLogLength);
glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
fprintf(stdout, "%sn", &FragmentShaderErrorMessage[0]);
// Create the program
fprintf(stdout, "Linking programn");
GLuint ProgramID = glCreateProgram();
glAttachShader(ProgramID, VertexShaderID);
glAttachShader(ProgramID, FragmentShaderID);
// Setup Vertex Attributes  [NEW]
glBindAttribLocation (ProgramID, 0, "vertexPosition_modelspace");
// Link the program
glLinkProgram(ProgramID);

机会是，此属性将被GLSL实现自动分配 0 ，一旦您删除了layout (location = 0)，但是您应该继续绑定并以正确的方式绑定位置。