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(GLEXT_glGenFramebuffers(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(GLEXT_glBindFramebuffer(GLEXT_GL_FRAMEBUFFER, m_frameBuffer));
// Create the depth buffer if requested
if (depthBuffer)
{
GLuint depth = 0;
glCheck(GLEXT_glGenRenderbuffers(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(GLEXT_glBindRenderbuffer(GLEXT_GL_RENDERBUFFER, m_depthBuffer));
glCheck(GLEXT_glRenderbufferStorage(GLEXT_GL_RENDERBUFFER, GLEXT_GL_DEPTH_COMPONENT, width, height));
glCheck(GLEXT_glFramebufferRenderbuffer(GLEXT_GL_FRAMEBUFFER, GLEXT_GL_DEPTH_ATTACHMENT, GLEXT_GL_RENDERBUFFER, m_depthBuffer));
}
// Link the texture to the frame buffer
glCheck(GLEXT_glFramebufferTexture2D(GLEXT_GL_FRAMEBUFFER, GLEXT_GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureId, 0));
// A final check, just to be sure...
GLenum status;
glCheck(status = GLEXT_glCheckFramebufferStatus(GLEXT_GL_FRAMEBUFFER));
if (status != GLEXT_GL_FRAMEBUFFER_COMPLETE)
{
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_FRAMEBUFFER, 0));
err() << "Impossible to create render texture (failed to link the target texture to the frame buffer)" << std::endl;
return false;
}
return true;
}
Image Texture::copyToImage() const
{
// Easy case: empty texture
if (!m_texture)
return Image();
ensureGlContext();
// Make sure that the current texture binding will be preserved
priv::TextureSaver save;
// Create an array of pixels
std::vector<Uint8> pixels(m_size.x * m_size.y * 4);
#ifdef SFML_OPENGL_ES
// OpenGL ES doesn't have the glGetTexImage function, the only way to read
// from a texture is to bind it to a FBO and use glReadPixels
GLuint frameBuffer = 0;
glCheck(GLEXT_glGenFramebuffers(1, &frameBuffer));
if (frameBuffer)
{
GLint previousFrameBuffer;
glCheck(glGetIntegerv(GLEXT_GL_FRAMEBUFFER_BINDING, &previousFrameBuffer));
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_FRAMEBUFFER, frameBuffer));
glCheck(GLEXT_glFramebufferTexture2D(GLEXT_GL_FRAMEBUFFER, GLEXT_GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_texture, 0));
glCheck(glReadPixels(0, 0, m_size.x, m_size.y, GL_RGBA, GL_UNSIGNED_BYTE, &pixels[0]));
glCheck(GLEXT_glDeleteFramebuffers(1, &frameBuffer));
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_FRAMEBUFFER, previousFrameBuffer));
}
#else
if ((m_size == m_actualSize) && !m_pixelsFlipped)
{
// Texture is not padded nor flipped, we can use a direct copy
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(glGetTexImage(GL_TEXTURE_2D, 0, GL_RGBA, GL_UNSIGNED_BYTE, &pixels[0]));
}
else
{
// Texture is either padded or flipped, we have to use a slower algorithm
// All the pixels will first be copied to a temporary array
std::vector<Uint8> allPixels(m_actualSize.x * m_actualSize.y * 4);
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(glGetTexImage(GL_TEXTURE_2D, 0, GL_RGBA, GL_UNSIGNED_BYTE, &allPixels[0]));
// Then we copy the useful pixels from the temporary array to the final one
const Uint8* src = &allPixels[0];
Uint8* dst = &pixels[0];
int srcPitch = m_actualSize.x * 4;
int dstPitch = m_size.x * 4;
// Handle the case where source pixels are flipped vertically
if (m_pixelsFlipped)
{
src += srcPitch * (m_size.y - 1);
srcPitch = -srcPitch;
}
for (unsigned int i = 0; i < m_size.y; ++i)
{
std::memcpy(dst, src, dstPitch);
src += srcPitch;
dst += dstPitch;
}
}
#endif // SFML_OPENGL_ES
// Create the image
Image image;
image.create(m_size.x, m_size.y, &pixels[0]);
return image;
}
void Texture::update(const Texture& texture, unsigned int x, unsigned int y)
{
assert(x + texture.m_size.x <= m_size.x);
assert(y + texture.m_size.x <= m_size.y);
if (!m_texture || !texture.m_texture)
return;
#ifndef SFML_OPENGL_ES
{
TransientContextLock lock;
// Make sure that extensions are initialized
priv::ensureExtensionsInit();
}
if (GLEXT_framebuffer_object && GLEXT_framebuffer_blit)
{
TransientContextLock lock;
// Save the current bindings so we can restore them after we are done
GLint readFramebuffer = 0;
GLint drawFramebuffer = 0;
glCheck(glGetIntegerv(GLEXT_GL_READ_FRAMEBUFFER_BINDING, &readFramebuffer));
glCheck(glGetIntegerv(GLEXT_GL_DRAW_FRAMEBUFFER_BINDING, &drawFramebuffer));
// Create the framebuffers
GLuint sourceFrameBuffer = 0;
GLuint destFrameBuffer = 0;
glCheck(GLEXT_glGenFramebuffers(1, &sourceFrameBuffer));
glCheck(GLEXT_glGenFramebuffers(1, &destFrameBuffer));
if (!sourceFrameBuffer || !destFrameBuffer)
{
err() << "Cannot copy texture, failed to create a frame buffer object" << std::endl;
return;
}
// Link the source texture to the source frame buffer
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_READ_FRAMEBUFFER, sourceFrameBuffer));
glCheck(GLEXT_glFramebufferTexture2D(GLEXT_GL_READ_FRAMEBUFFER, GLEXT_GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture.m_texture, 0));
// Link the destination texture to the destination frame buffer
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_DRAW_FRAMEBUFFER, destFrameBuffer));
glCheck(GLEXT_glFramebufferTexture2D(GLEXT_GL_DRAW_FRAMEBUFFER, GLEXT_GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_texture, 0));
// A final check, just to be sure...
GLenum sourceStatus;
glCheck(sourceStatus = GLEXT_glCheckFramebufferStatus(GLEXT_GL_READ_FRAMEBUFFER));
GLenum destStatus;
glCheck(destStatus = GLEXT_glCheckFramebufferStatus(GLEXT_GL_DRAW_FRAMEBUFFER));
if ((sourceStatus == GLEXT_GL_FRAMEBUFFER_COMPLETE) && (destStatus == GLEXT_GL_FRAMEBUFFER_COMPLETE))
{
// Blit the texture contents from the source to the destination texture
glCheck(GLEXT_glBlitFramebuffer(0, 0, texture.m_size.x, texture.m_size.y, x, y, x + texture.m_size.x, y + texture.m_size.y, GL_COLOR_BUFFER_BIT, GL_NEAREST));
}
else
{
err() << "Cannot copy texture, failed to link texture to frame buffer" << std::endl;
}
// Restore previously bound framebuffers
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_READ_FRAMEBUFFER, readFramebuffer));
glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_DRAW_FRAMEBUFFER, drawFramebuffer));
// Delete the framebuffers
glCheck(GLEXT_glDeleteFramebuffers(1, &sourceFrameBuffer));
glCheck(GLEXT_glDeleteFramebuffers(1, &destFrameBuffer));
return;
}
#endif // SFML_OPENGL_ES
update(texture.copyToImage(), x, y);
}
