Question

大家好我试图使用着色器学习openGL所以我做了一个三角形，它在移动时改变了颜色但是由于某种原因，三角形没有出现在窗口中，只是一个黑色的背景，它不会崩溃或显示任何一种错误，我相信库设置是好的，因为我之前使用过它们。我在Ubuntu 16.04上使用CLion。这是我的代码，所以希望你可以检查出来并给我一个帮助。谢谢！

#define GLEW_STATIC

#include <stdlib.h>
#include <stdio.h>
#include <GL/glew.h>
#include <GL/freeglut.h>
#include <iostream>


int CurrentWidth = 800,
CurrentHeight = 600,
WindowHandle = 0;

GLuint
    VertexShaderId,
    FragmentShaderId,
    ProgramId;

GLuint s_vertexLoc, s_colorLoc , s_factorLoc;

GLfloat  runner = 0.0;

const GLchar* VertexShader =
    {
            "#version 150\n"
            "attribute vec3 in_vertex;"
            "attribute vec3 in_color;"

            "uniform float factor;"

            "varying vec3 intp_color;"

            "void main(void)"
            "{"
                "intp_color = in_color;"
                "gl_Position = vec4( in_vertex , 1.0 ) ;"
                "gl_Position.y += factor; "
            "}"

    };

//Telling every single pixel is going to be red
const GLchar* FragmentShader =
    {
            "#version 150\n"
            "uniform float factor;"
            "varying vec3 intp_color;"
            "void main(void){"
                "gl_FragColor = vec4( intp_color , 1.0) * factor;"
            "}"
    };


// for. dec.
void ResizeFunction(int, int);
void RenderFunction(void);
void IdleFunction(void);
void CreateShaders(void);



// set up an array for the geometry of the object
GLfloat Vertices[] = {
    -0.5f , -0.2f , 0.0f, // point A - x , y , z
    0.5f , -0.2f , 0.0f, // point B - x , y , z
    0.0f ,  0.8f , 0.0f  // point C - x , y , z
};

GLfloat Colors[] = {
    1.0f , 0.0f , 0.0f, // point A - x , y , z
    0.0f , 1.0f , 0.0f, // point B - x , y , z
    0.0f , 0.0f , 1.0f  // point C - x , y , z
};


int main( int argc , char* argv[] )
{
glutInit( &argc , argv);

//Target version 3.1
glutInitContextVersion(3 , 1 );

glutInitWindowSize(CurrentWidth, CurrentHeight);
glutInitDisplayMode( GLUT_DEPTH | GLUT_DOUBLE |     GLUT_RGBA );

WindowHandle = glutCreateWindow( "OpenGL - Shader example" );

glutReshapeFunc( ResizeFunction );
glutDisplayFunc( RenderFunction );
glutIdleFunc( IdleFunction );

/// init GLEW
GLenum GlewInitResult;
GlewInitResult = glewInit();

if (GLEW_OK != GlewInitResult)
    exit(EXIT_FAILURE);

/// Create our shaders
CreateShaders();

glutMainLoop();

exit(EXIT_SUCCESS);
}


void ResizeFunction(int Width, int Height)
{
CurrentWidth = Width;
CurrentHeight = Height;
glViewport( 0, 0, CurrentWidth, CurrentHeight );
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
}

void RenderFunction(void)
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

//We enable the shader variable
glEnableVertexAttribArray( s_vertexLoc );
glEnableVertexAttribArray( s_colorLoc );

//How to send data to the variable:
//( Where to send the data , how its grouped , data type , dont normalize the data,
// there is no offset, you find it here)

glVertexAttribPointer( s_vertexLoc , 3 , GL_FLOAT , GL_FALSE , 0 , Vertices );
glVertexAttribPointer ( s_colorLoc , 3 , GL_FLOAT , GL_FALSE , 0 , Colors);

glUniform1f( s_factorLoc , runner );
runner += 0.01;
if(runner > 1.0f)
    runner = -1.0f;

glDrawArrays( GL_TRIANGLES , 0 , 3 );

glDisableVertexAttribArray( s_vertexLoc );
glDisableVertexAttribArray( s_colorLoc );

glutSwapBuffers();
  }

void IdleFunction(void)
{
glutPostRedisplay();
}

//Error checking
void printLog(GLuint obj)
{
int infologLength = 0;
int maxLength;

if( glIsShader( obj ) )
    glGetShaderiv( obj , GL_INFO_LOG_LENGTH , &maxLength );
else
    glGetProgramiv( obj, GL_INFO_LOG_LENGTH, &maxLength);

char infoLog[1255];

if ( glIsShader(obj) )
    glGetShaderInfoLog( obj, maxLength, &infologLength, infoLog );
else
    glGetProgramInfoLog( obj, maxLength, &infologLength, infoLog );

if ( infologLength > 0 )
    printf( "\n Error detail: %s\n" , infoLog );
}


void CreateShaders(void)
{
GLenum ErrorCheckValue = glGetError();

if( glCreateShader )
    printf(" ---- shader suppot ok ---");
else
{
    printf(" ---- no shader support ---");
    return ;
}

///The VERTEX shader is created (tell it what it is)
VertexShaderId = glCreateShader( GL_VERTEX_SHADER );
//(shader we want to set the source, how many are they, the source of the shader , )
glShaderSource( VertexShaderId , 1 , &VertexShader , nullptr );
//Compile the shader
glCompileShader( VertexShaderId );

//Error checking
printLog( VertexShaderId );


///The FRAGMENT shader is created (tell it what it is)
FragmentShaderId = glCreateShader( GL_FRAGMENT_SHADER );
//(shader we want to set the source, how many are they, the source of the shader , )
glShaderSource( FragmentShaderId , 1 , &FragmentShader , nullptr );
//Compile the shader
glCompileShader( FragmentShaderId );

//Error checking
printLog( FragmentShaderId );


///Program Object links both shaders
ProgramId = glCreateProgram();
//Attach the compiled shaders to the program
glAttachShader( ProgramId , VertexShaderId );
glAttachShader( ProgramId , FragmentShaderId );
//Links the shaders to the program
glLinkProgram( ProgramId );

//Error checking
printLog( ProgramId );

//Uses the program to render
glUseProgram( ProgramId );

//( check this program , for this variable and return it)
s_vertexLoc = glGetAttribLocation( ProgramId , "in_vertex" );
s_colorLoc = glGetAttribLocation( ProgramId , "in_color" );
s_factorLoc = glGetUniformLocation( ProgramId , "factor" );
}

Answer 1

你有几个问题。

首先，不建议使用OpenGL 3.1（GLSL 1.30）。至少尝试一下 3.2（GLSL 1.50）并在您的初始化过程中询问Core Profile。然后替换＆＃34; 属性＆＃34;使用＆＃34; ＆＃34;在你的顶点着色器和＆＃34; 变化＆＃34;使用＆＃34; ＆＃34;或＆＃34; out ＆＃34;根据如果此var将用作输入或输出。
二。此

//如何将数据发送到变量： //（在哪里发送数据，如何分组，数据类型，不规范化数据， //没有偏移，你在这里找到）

glVertexAttribPointer（s_vertexLoc，3，GL_FLOAT，GL_FALSE，0，Vertices）; glVertexAttribPointer（s_colorLoc，3，GL_FLOAT，GL_FALSE，0，Colors）;

不是真的。最后一个值是字节偏移到缓冲区对象的数据存储，不数据本身。
第三：你的顶点坐标需要一个缓冲区。使用 glGenBuffers()，glBufferData()和glBindBuffer()

如果我在你的情况下，我会按照现代OpenGL＆＃34;进行一些教程。在网上搜索，有很多。

OpenGL三角形没有出现

1 个答案: