I am getting an error when trying to use VAO's inside of SFML and not sure if it is SFML or it is my own opengl code
GLenum err = glewInit();
if (err != GLEW_OK)
{
std::cout << "NOT WORKING" << std::endl;
}
std::vector<sf::Vector3f> g_vertext_buffer_data;
g_vertex_buffer_data.push_back({ -1.0f, -1.0f, 0.0f });
g_vertex_buffer_data.push_back({1.0f, -1.0f, 0.0f});
g_vertex_buffer_data.push_back({ 0.0f, 1.0f, 0.0f });
const char* vertexShaderSource =
"#version 330\n\
in vec4 position;\
void main(void){\ gl_Position = position;\
}";
// compile fragment shader source
const GLchar* fragmentShaderSource =
"#version 330\n\
void main(void) {\
out vec4 fragcolor; fragcolor= vec4(1.0,1.0,1.0,1.0);\
}";
/* Creating Shader */
this->programId = glCreateProgram();
this->vId = glCreateShader(GL_VERTEX_SHADER);
this->fId = glCreateShader(GL_FRAGMENT_SHADER);
/* Get Shader Size */
int vertexShaderLength = strlen(vertexShaderSource);
int fragmentShaderLength = strlen(fragmentShaderSource);
/* Loading and binding shader */
glShaderSource(this->vId, 1, &vertexShaderSource, NULL);
glShaderSource(this->fId, 1, &fragmentShaderSource, NULL);
/* Compile Shaders */
glCompileShader(vId);
glCompileShader(fId);
/* Attach Shaders */
glAttachShader(this->programId, this->vId);
glAttachShader(this->programId, this->fId);
/* Linkg program */
glLinkProgram(this->programId);
/* Use and bind attribute */
glUseProgram(this->programId);
this->positionId = glGetAttribLocation(this->programId, "position");
glUseProgram(0);
/* VAO Time */
glGenVertexArrays(1, &this->vaoId);
glBindVertexArray(this->vaoId);
/* VBO Time assigning to VAO */
glGenBuffers(1, &this->vboId);
glBindBuffer(GL_ARRAY_BUFFER, this->vboId);
glBufferData(GL_ARRAY_BUFFER, g_vertex_buffer_data.size() * sizeof(sf::Vector3f), &g_vertex_buffer_data[0], GL_STATIC_DRAW);
glEnableVertexAttribArray(this->positionId);
glVertexAttribPointer(this->positionId, 2, GL_FLOAT, GL_FALSE, sizeof(sf::Vector3f), 0);
/* Close out bindings */
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
while(1)
{
glUseProgram(this->programId);
glBindVertexArray(this->vaoId);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);
glUseProgram(0);
gameWindow.glPushStates();
}
The error code I get is: opengl error in user code (1282)
I have changed the size() issue that was brought up in the blBufferData() but still am getting the issue.
Possible error codes for glGetAttribLocation are:
GL_INVALID_OPERATION
Which don't have a fixed value. Try to get the error string with gluErrorString() or take a look in the header to which of those 1282 maps.
• check your shader got compiled without error?
• check your shader got linked without error?
What type have positionId? All object id's must be GLuint type.
And btw allways enable shader compilation-linking error check, and debug will be more informative.
I do that in this way (OpenGL-ES 2.0):
m_nVertexShader = glCreateShader(GL_VERTEX_SHADER);
m_nPixelShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(m_nVertexShader, 1, &lpszVertexBuffer, NULL);
glShaderSource(m_nPixelShader, 1, &lpszFragmentBuffer, NULL);
glCompileShader(m_nVertexShader);
int iIsOk = 0;
glGetShaderiv(m_nVertexShader, GL_COMPILE_STATUS, &iIsOk);
if(!iIsOk)
{
GLint infoLen = 0;
glGetShaderiv(m_nVertexShader, GL_INFO_LOG_LENGTH, &infoLen);
if(infoLen > 1)
{
char* infoLog = (char*)malloc(sizeof(char) * infoLen);
glGetShaderInfoLog(m_nVertexShader, infoLen, NULL, infoLog);
QMessageBox::warning(this, QString("Error"),
QString(infoLog), QMessageBox::Yes | QMessageBox::Cancel, QMessageBox::Yes);
free(infoLog);
}
glDeleteShader(m_nVertexShader);
return;
}
glCompileShader(m_nPixelShader);
glGetShaderiv(m_nPixelShader, GL_COMPILE_STATUS, &iIsOk);
if(!iIsOk)
{
GLint infoLen = 0;
glGetShaderiv(m_nPixelShader, GL_INFO_LOG_LENGTH, &infoLen);
if(infoLen > 1)
{
char* infoLog = (char*)malloc(sizeof(char) * infoLen);
glGetShaderInfoLog(m_nPixelShader, infoLen, NULL, infoLog);
QMessageBox::warning(this, QString("Error"),
QString(infoLog), QMessageBox::Yes | QMessageBox::Cancel, QMessageBox::Yes);
free(infoLog);
}
glDeleteShader(m_nPixelShader);
return;
}
m_nProgram = glCreateProgram();
glAttachShader(m_nProgram, m_nVertexShader);
glAttachShader(m_nProgram, m_nPixelShader);
glBindAttribLocation(m_nProgram, 0, "rm_Vertex");
glLinkProgram(m_nProgram);
glGetProgramiv(m_nProgram, GL_LINK_STATUS, &iIsOk);
// Fail to pass status validation
if(!iIsOk)
{
GLint infoLen = 0;
glGetProgramiv(m_nProgram, GL_INFO_LOG_LENGTH, &infoLen);
if(infoLen > 1)
{
char* infoLog = (char*)malloc(sizeof(char) * infoLen);
glGetProgramInfoLog(m_nProgram, infoLen, NULL, infoLog);
QMessageBox::warning(this, QString("Error"),
QString(infoLog), QMessageBox::Yes | QMessageBox::Cancel, QMessageBox::Yes);
free(infoLog);
}
glDeleteProgram(m_nProgram);
return;
}
glUseProgram(m_nProgram);
As you use GLSL 3.3, fist you must specify fragment rendertarget output by calling
glBindFragDataLocation(this->programId, 0, "fragcolor");
Secondly your fragment shader must be like
"#version 330
out vec4 fragcolor;
void main(void) {
fragcolor= vec4(1.0,1.0,1.0,1.0);
}
The example of using this kind of shaders is on OpenGL 3.3 + GLSL 1.5 Sample.