问题
The shaders in my OpenGL project don't compile. I have Ubuntu 16.04 LTS, using CLion. Didn't find any solution, that's why asking here.
Here is my errorlist:
ATTENTION: default value of option force_s3tc_enable overridden by environment.
ERROR::SHADER::VERTEX::COMPILATION_FAILED
0:1(1): error: syntax error, unexpected $end
ERROR::SHADER::FRAGMENT::COMPILATION_FAILED
0:1(1): error: syntax error, unexpected $end
ERROR::SHADER::PROGRAM::LINKING_FAILED
error: linking with uncompiled shadererror: linking with uncompiled shader
Here's my main.cpp code:
#include <iostream>
// GLEW
#define GLEW_STATIC
#include <GL/glew.h>
// GLFW
#include <GLFW/glfw3.h>
// Other includes
#include "Shader.h"
// Window dimensions
const GLuint WIDTH = 800, HEIGHT = 600;
// The MAIN function, from here we start the application and run the game loop
int main( )
{
// Init GLFW
glfwInit( );
// Set all the required options for GLFW
glfwWindowHint( GLFW_CONTEXT_VERSION_MAJOR, 3 );
glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 3 );
glfwWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE );
glfwWindowHint( GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE );
glfwWindowHint( GLFW_RESIZABLE, GL_FALSE );
// Create a GLFWwindow object that we can use for GLFW's functions
GLFWwindow *window = glfwCreateWindow( WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr );
int screenWidth, screenHeight;
glfwGetFramebufferSize( window, &screenWidth, &screenHeight );
if ( nullptr == window )
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate( );
return EXIT_FAILURE;
}
glfwMakeContextCurrent( window );
// Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
glewExperimental = GL_TRUE;
// Initialize GLEW to setup the OpenGL Function pointers
if ( GLEW_OK != glewInit( ) )
{
std::cout << "Failed to initialize GLEW" << std::endl;
return EXIT_FAILURE;
}
// Define the viewport dimensions
glViewport( 0, 0, screenWidth, screenHeight );
// Build and compile our shader program
Shader ourShader( "core.vs", "core.frag" );
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] =
{
// Positions // Colors
0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, // Bottom Right
-0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, // Bottom Left
0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f // Top
};
GLuint VBO, VAO;
glGenVertexArrays( 1, &VAO );
glGenBuffers( 1, &VBO );
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray( VAO );
glBindBuffer( GL_ARRAY_BUFFER, VBO );
glBufferData( GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW );
// Position attribute
glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof( GLfloat ), ( GLvoid * ) 0 );
glEnableVertexAttribArray( 0 );
// Color attribute
glVertexAttribPointer( 1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof( GLfloat ), ( GLvoid * )( 3 * sizeof( GLfloat ) ) );
glEnableVertexAttribArray( 1 );
glBindVertexArray( 0 ); // Unbind VAO
// Game loop
while ( !glfwWindowShouldClose( window ) )
{
// Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
glfwPollEvents( );
// Render
// Clear the colorbuffer
glClearColor( 0.2f, 0.3f, 0.3f, 1.0f );
glClear( GL_COLOR_BUFFER_BIT );
// Draw the triangle
ourShader.Use( );
glBindVertexArray( VAO );
glDrawArrays( GL_TRIANGLES, 0, 3 );
glBindVertexArray(0);
// Swap the screen buffers
glfwSwapBuffers( window );
}
// Properly de-allocate all resources once they've outlived their purpose
glDeleteVertexArrays( 1, &VAO );
glDeleteBuffers( 1, &VBO );
// Terminate GLFW, clearing any resources allocated by GLFW.
glfwTerminate( );
return EXIT_SUCCESS;
}
Shader.h code:
#ifndef SHADER_H
#define SHADER_H
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <GL/glew.h>
#include <cstring>
class Shader
{
public:
GLuint Program;
// Constructor generates the shader on the fly
Shader( const GLchar *vertexPath, const GLchar *fragmentPath )
{
// 1. Retrieve the vertex/fragment source code from filePath
std::string vertexCode;
std::string fragmentCode;
std::ifstream vShaderFile;
std::ifstream fShaderFile;
// ensures ifstream objects can throw exceptions:
vShaderFile.exceptions ( std::ifstream::badbit );
fShaderFile.exceptions ( std::ifstream::badbit );
try
{
// Open files
vShaderFile.open( vertexPath );
fShaderFile.open( fragmentPath );
std::stringstream vShaderStream, fShaderStream;
// Read file's buffer contents into streams
vShaderStream << vShaderFile.rdbuf( );
fShaderStream << fShaderFile.rdbuf( );
// close file handlers
vShaderFile.close( );
fShaderFile.close( );
// Convert stream into string
vertexCode = vShaderStream.str( );
fragmentCode = fShaderStream.str( );
}
catch ( std::ifstream::failure e )
{
std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
}
const GLchar *vShaderCode = vertexCode.c_str( );
const GLchar *fShaderCode = fragmentCode.c_str( );
// 2. Compile shaders
GLuint vertex, fragment;
GLint success;
GLchar infoLog[512];
// Vertex Shader
vertex = glCreateShader( GL_VERTEX_SHADER );
glShaderSource( vertex, 1, &vShaderCode, NULL);
glCompileShader( vertex );
// Print compile errors if any
glGetShaderiv( vertex, GL_COMPILE_STATUS, &success );
if ( !success )
{
glGetShaderInfoLog( vertex, 512, NULL, infoLog );
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Fragment Shader
fragment = glCreateShader( GL_FRAGMENT_SHADER );
glShaderSource( fragment, 1, &fShaderCode, NULL);
glCompileShader( fragment );
// Print compile errors if any
glGetShaderiv( fragment, GL_COMPILE_STATUS, &success );
if ( !success )
{
glGetShaderInfoLog( fragment, 512, NULL, infoLog );
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Shader Program
this->Program = glCreateProgram( );
glAttachShader( this->Program, vertex );
glAttachShader( this->Program, fragment );
glLinkProgram( this->Program );
// Print linking errors if any
glGetProgramiv( this->Program, GL_LINK_STATUS, &success );
if (!success)
{
glGetProgramInfoLog( this->Program, 512, NULL, infoLog );
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
// Delete the shaders as they're linked into our program now and no longer necessery
glDeleteShader( vertex );
glDeleteShader( fragment );
}
// Uses the current shader
void Use( )
{
glUseProgram( this->Program );
}
};
#endif
Here's my core.vs:
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 color;
layout (location = 2) in vec2 texCoord;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(position, 1.0f);
ourColor = color;
// We swap the y-axis by substracing our coordinates from 1. This is done because most images have the top y-axis inversed with OpenGL's top y-axis.
// TexCoord = texCoord;
TexCoord = vec2(texCoord.x, 1.0 - texCoord.y);
}
...and core.frag:
#version 330 core
in vec3 ourColor;
in vec2 TexCoord;
out vec4 color;
// Texture samplers
uniform sampler2D ourTexture1;
void main()
{
// Linearly interpolate between both textures (second texture is only slightly combined)
color = texture(ourTexture1, TexCoord);
}
I've also attached my CMakeLists.txt. Hope it helps:
cmake_minimum_required(VERSION 3.9)
project(STUDY_GL)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -pthread -fpermissive")
find_package (OpenGL REQUIRED)
find_package (GLUT REQUIRED)
find_package (glfw3 REQUIRED)
find_library (glew REQUIRED)
find_library (glad REQUIRED)
include_directories(${/usr/include/GLFW/})
include_directories(${/usr/include/GL/})
file(GLOB SOURCE_FILES
*.cpp
*.h
)
add_executable(main.cpp ${SOURCE_FILES} Shader.h)
target_link_libraries (main.cpp ${OPENGL_LIBRARIES} ${GLUT_LIBRARIES} ${GLFW3_LIBRARIES} -lGL -lglfw -lglut -lGLEW)
I have an SOIL2 directory inside a project. Here's its link.
回答1:
In general you code is fine, but you have to pass std::ifstream::failbit to std::ios::exceptions, because if std::ifstream::open fails, the failbit state flag is set.
vShaderFile.exceptions ( std::ifstream::failbit | std::ifstream::badbit );
fShaderFile.exceptions ( std::ifstream::failbit | std::ifstream::badbit );
try
{
vShaderFile.open( vertexPath );
fShaderFile.open( fragmentPath );
.....
}
catch ( std::ifstream::failure e )
{
std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
}
I bet that your working directory is not proper set. Use an absolute file path to the shader files for debug reasons.
If the shader source files cannot be accessed, and your code does not throw any exception, then you try to compile empty strings. This causes the error messages.
By the way, since you do not use any texture in the code snippet posted in your question, you should do the following changes to your fragment shader:
// color = texture(ourTexture1, TexCoord); <--- skip
color = vec4(ourColor,1.0); <--- add
回答2:
The error you see normally happens, when shader source without a null terminator at the end is passed to glShaderSource without specifying the source string length. Since typical files usually don't contain a null terminator, OpenGL will read past the end of the source string.
The solution is to pass in the exact length of the shader source string.
来源：https://stackoverflow.com/questions/47853523/opengl-shaders-dont-compile