The SDL forums have moved to discourse.libsdl.org.
This is just a read-only archive of the previous forums, to keep old links working.


SDL Forum Index
SDL
Simple Directmedia Layer Forums
How to use FBO with SDL ???
Lolilolight


Joined: 07 Jun 2014
Posts: 17
Hi!

I'm trying to use FBO with SDL but it doesn't work, when I try to link my FBO to the texture I get this error :

An internal call failed in renderTextureImplFBO.cpp (117) : GL_INALID_OPERATION, the specified operation is not allowed in the current state.

Impossible to create render texture. (failed to link the target texture to the framebuffer)

Here is the code :

[code]
////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2013 Laurent Gomila
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
// you must not claim that you wrote the original software.
// If you use this software in a product, an acknowledgment
// in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
// and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include "renderTextureImplFBO.h"
#include "../../../include/odfaeg/Graphics/texture.h"
#include "glCheck.h"
#include <SFML/System/Err.hpp>
#include <iostream>
using namespace sf;
namespace odfaeg {

namespace priv
{
////////////////////////////////////////////////////////////
RenderTextureImplFBO::RenderTextureImplFBO() :
m_frameBuffer(0),
m_depthBuffer(0)
{

}


////////////////////////////////////////////////////////////
RenderTextureImplFBO::~RenderTextureImplFBO()
{
ensureGlContext();

// Destroy the depth buffer
if (m_depthBuffer)
{
GLuint depthBuffer = static_cast<GLuint>(m_depthBuffer);
glCheck(glDeleteRenderbuffersEXT(1, &depthBuffer));
}

// Destroy the frame buffer
if (m_frameBuffer)
{
GLuint frameBuffer = static_cast<GLuint>(m_frameBuffer);
glCheck(glDeleteFramebuffersEXT(1, &frameBuffer));
}

// Delete the context
delete m_context;
}


////////////////////////////////////////////////////////////
bool RenderTextureImplFBO::isAvailable()
{
ensureGlContext();

// Make sure that GLEW is initialized
priv::ensureGlewInit();

return GLEW_EXT_framebuffer_object != 0;
}


////////////////////////////////////////////////////////////
bool RenderTextureImplFBO::create(unsigned int width, unsigned int height, unsigned int textureId, bool depthBuffer)
{
// Create the context
m_context = new Context;

// Create the framebuffer object
GLuint frameBuffer = 0;
glCheck(glGenFramebuffersEXT(1, &frameBuffer));
m_frameBuffer = static_cast<unsigned int>(frameBuffer);
if (!m_frameBuffer)
{
err() << "Impossible to create render texture (failed to create the frame buffer object)" << std::endl;
return false;
}
glCheck(glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_frameBuffer));

// Create the depth buffer if requested
if (depthBuffer)
{
GLuint depth = 0;
glCheck(glGenRenderbuffersEXT(1, &depth));
m_depthBuffer = static_cast<unsigned int>(depth);
if (!m_depthBuffer)
{
err() << "Impossible to create render texture (failed to create the attached depth buffer)" << std::endl;
return false;
}
glCheck(glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, m_depthBuffer));
glCheck(glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, width, height));
glCheck(glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, m_depthBuffer));
}

// Link the texture to the frame buffer
glCheck(glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, textureId, 0));

// A final check, just to be sure...
if (glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) != GL_FRAMEBUFFER_COMPLETE_EXT)
{
glCheck(glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0));
err() << "Impossible to create render texture (failed to link the target texture to the frame buffer)" << std::endl;
return false;
}

return true;
}


////////////////////////////////////////////////////////////
bool RenderTextureImplFBO::activate(bool active)
{
return m_context->setActive(active);
}


////////////////////////////////////////////////////////////
void RenderTextureImplFBO::updateTexture(unsigned int)
{
glFlush();
}

} // namespace priv

} // namespace sf
Lolilolight


Joined: 07 Jun 2014
Posts: 17
Here is the screen that I get, and, without FBO everything is well drawn :

http://www.hostingpics.net/viewer.php?id=934708Capturedu20140608202020.png
Lolilolight


Joined: 07 Jun 2014
Posts: 17
I've commented the line with instanciate a new context..., and the error message dissappeared but still have that odd screen, should I use a new opengl context when I create an FBO ???
Lolilolight


Joined: 07 Jun 2014
Posts: 17
Finally, I'm coming back to SFML, SDL support more plateform but it doesn't seems to be very stable yet. (Especially with FBO and newest opengl versions)