我试图用我的 VBO/OpenGL 练习解决一个错误，但几个小时(几天)后，我找不到问题所在。
问题是窗口保持黑色，未(正确)绘制立方体。
-
OpenGL 上下文似乎是为 OpenGL 3.2 正确创建的
顶点着色器:
#version 150 core
uniform mat4 RotationMatrix;
uniform mat4 ProjectionMatrix;
in vec3 in_Position;
void main(void)
{
gl_Position = ProjectionMatrix * RotationMatrix * vec4(in_Position, 1.0);
}
VBO初始化:
// <-- Create OpenGL 3.2 context
// <-- Load Shaders
// <-- Set ClearColor, clearDepth, DepthFUnc, enable Depth
// <-- Set Viewport, init projection and modelview matrix.
float positionData[] =
{
-0.5f, 0.5f, -0.5f,
0.5f, 0.5f, -0.5f,
0.5f, -0.5f, -0.5f,
-0.5f, -0.5f, -0.5f,
-0.5f, 0.5f, 0.5f,
0.5f, 0.5f, 0.5f,
0.5f, -0.5f, 0.5f,
-0.5f, -0.5f, 0.5f,
};
GLuint indexes[] =
{
0, 1, 2, 0, 2, 3,
4, 5, 6, 4, 6, 7,
0, 3, 7, 0, 7, 4,
1, 5, 6, 1, 6, 2,
0, 4, 5, 0, 5, 1,
2, 3, 7, 2, 7, 6
};
glGenBuffers(2, vboHandles);
glBindBuffer( GL_ARRAY_BUFFER, vboHandles[0]);
glBufferData(GL_ARRAY_BUFFER, 24*sizeof(float), positionData, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboHandles[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, 36*sizeof(GLuint),
indexes, GL_STATIC_DRAW);
在OpenGL绘制函数中:
//<--Clear buffer, set Uniform variables for projection and modelview
glBindBuffer(GL_ARRAY_BUFFER, vboHandles[0]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboHandles[1]);
glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_INT, NULL);
//<-- Flush Opengl and swap buffers
正确/不正确
已编辑:片段着色器:
#version 150 core
out vec4 out_Color;
void main(void){
out_Color = vec4(1.0, 0.0, 0.0, 1.0f);
}
编辑 2:添加上下文创建
SDL_Window* window;
SDL_GLContext context;
if (SDL_Init(SDL_INIT_VIDEO) < 0) {
return 0;
}
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
if ((window = SDL_CreateWindow( "Practica 4 and lot of stuff for the final prictice",
SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
800, 600, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN)) == NULL)
{
SDL_Quit();
return 0;
}
if (NULL== (context = SDL_GL_CreateContext(window)))
{
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
glewExperimental = GL_TRUE;
GLuint glewStatus = glewInit();
if (glewStatus != GLEW_OK)
{
cout << "Error" << endl;
}
最佳答案
在这里工作得很好:
#include <GL/glew.h>
#include <GL/freeglut.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
using namespace glm;
#include <iostream>
using namespace std;
struct Program
{
static GLuint Load( const char* vert, const char* geom, const char* frag )
{
GLuint prog = glCreateProgram();
if( vert ) AttachShader( prog, GL_VERTEX_SHADER, vert );
if( geom ) AttachShader( prog, GL_GEOMETRY_SHADER, geom );
if( frag ) AttachShader( prog, GL_FRAGMENT_SHADER, frag );
glLinkProgram( prog );
CheckStatus( prog );
return prog;
}
private:
static void CheckStatus( GLuint obj )
{
GLint status = GL_FALSE;
if( glIsShader(obj) ) glGetShaderiv( obj, GL_COMPILE_STATUS, &status );
if( glIsProgram(obj) ) glGetProgramiv( obj, GL_LINK_STATUS, &status );
if( status == GL_TRUE ) return;
GLchar log[ 1 << 15 ] = { 0 };
if( glIsShader(obj) ) glGetShaderInfoLog( obj, sizeof(log), NULL, log );
if( glIsProgram(obj) ) glGetProgramInfoLog( obj, sizeof(log), NULL, log );
std::cerr << log << std::endl;
exit( -1 );
}
static void AttachShader( GLuint program, GLenum type, const char* src )
{
GLuint shader = glCreateShader( type );
glShaderSource( shader, 1, &src, NULL );
glCompileShader( shader );
CheckStatus( shader );
glAttachShader( program, shader );
glDeleteShader( shader );
}
};
#define GLSL(version, shader) "#version " #version "\n" #shader
const char* vert = GLSL
(
150 core,
uniform mat4 RotationMatrix;
uniform mat4 ProjectionMatrix;
in vec3 in_Position;
void main(void)
{
gl_Position = ProjectionMatrix * RotationMatrix * vec4(in_Position, 1.0);
}
);
const char* frag = GLSL
(
150 core,
out vec4 out_Color;
void main(void){
out_Color = vec4(1.0, 0.0, 0.0, 1.0f);
}
);
GLuint vbo = 0;
GLuint ibo = 0;
void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
double w = glutGet( GLUT_WINDOW_WIDTH );
double h = glutGet( GLUT_WINDOW_HEIGHT );
double ar = w / h;
mat4 projection = glm::ortho< float >( -1 * ar, 1 * ar, -1.0, 1.0, -1.0, 1.0 );
mat4 modelview = mat4( 1.0 );
// prepare to render
static GLuint prog = Program::Load( vert, NULL, frag );
glUseProgram( prog );
GLint proj = glGetUniformLocation( prog, "ProjectionMatrix" );
glUniformMatrix4fv( proj, 1, GL_FALSE, glm::value_ptr( projection ) );
GLint model = glGetUniformLocation( prog, "RotationMatrix" );
glUniformMatrix4fv( model, 1, GL_FALSE, glm::value_ptr( modelview ) );
float positionData[] =
{
-0.5f, 0.5f, -0.5f,
0.5f, 0.5f, -0.5f,
0.5f, -0.5f, -0.5f,
-0.5f, -0.5f, -0.5f,
-0.5f, 0.5f, 0.5f,
0.5f, 0.5f, 0.5f,
0.5f, -0.5f, 0.5f,
-0.5f, -0.5f, 0.5f,
};
glBindBuffer( GL_ARRAY_BUFFER, vbo );
glBufferData( GL_ARRAY_BUFFER, sizeof( positionData ), positionData, GL_STREAM_DRAW );
GLuint indexes[] =
{
0, 1, 2, 0, 2, 3,
4, 5, 6, 4, 6, 7,
0, 3, 7, 0, 7, 4,
1, 5, 6, 1, 6, 2,
0, 4, 5, 0, 5, 1,
2, 3, 7, 2, 7, 6
};
glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, ibo );
glBufferData( GL_ELEMENT_ARRAY_BUFFER, sizeof( indexes ), indexes, GL_STREAM_DRAW );
GLint pos = glGetAttribLocation( prog, "in_Position" );
glVertexAttribPointer( pos, 3, GL_FLOAT, GL_FALSE, 0, 0 );
glEnableVertexAttribArray( pos );
glDrawElements( GL_TRIANGLES, sizeof( indexes ) / sizeof( GLuint ), GL_UNSIGNED_INT, 0 );
glutSwapBuffers();
}
int main(int argc, char **argv)
{
glutInit( &argc, argv );
glutInitContextVersion( 3, 2 );
glutInitContextProfile( GLUT_CORE_PROFILE );
glutInitDisplayMode( GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE );
glutInitWindowSize( 600, 600 );
glutCreateWindow( "GLUT" );
glewExperimental = GL_TRUE;
glewInit();
GLuint vao = 0;
glGenVertexArrays( 1, &vao );
glBindVertexArray( vao );
glGenBuffers( 1, &vbo );
glGenBuffers( 1, &ibo );
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
关于c++ - 在OpenGL中实现VBO，窗口保持黑色，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23204054/