[Request] Add framebuffer back to the BGL wrapper

[HG1-Public]

Dalai Felinto has added framebuffer to the BGL wrapper. But after the has fished his offscreen patch he has removed it from the BGL wrapper.
I need it back, because I need more control over the frame buffer (eg. glReadPixels).
Basically I need to bind the buffer with glBindFramebuffer.
commit d3a1b465ba61f0577dec2615e332a686ec3032fb
revert commit 18d5ac5b55cba40835a9b513347b87f658d9bad5

It would be also useful, if there would be attribute which would return the actual framebuffer ID.
Actually I use GL_READ_FRAMEBUFFER_BINDING to get the actual framebuffer ID. Which is not 100% save if you use multiple framebuffer.
readFboId = Buffer(GL_INT, 1)
glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, readFboId) # for backwards compatibility, GL_FRAMEBUFFER_BINDING is equivalent to GL_DRAW_FRAMEBUFFER_BINDING

[solhrdulik69]

Yeah, and speed up for glReadPixels

[panzergame]

@HG1-Public, hrm, i could not find the commit hash in the latest blender/master...

[HG1-Public]

Somebody has deleted the branch so the patch is not available any more. But I found a backup on Google http://bf-blender-cvs.blender.narkive.com/45UvaV0h/d3a1b46-framebuffer-bgl-gl-3-0-methods-framebuffer-related.

I updated the path for the UPBGE.
BGL GL 3.0 methods (Framebuffer related)2.diff.zip

@solhrdulik69 you can't speed up glReadPixels it self. The only way is to use a PBO to speed up the reading.

[panzergame]

Could you test again in master ?

[HG1-Public]

I can't test every function call. I modified my sound shader example (glBindFramebuffer) and works fine.
https://blenderartists.org/forum/showthread.php?434833-Music-from-sound-shader

I also tested it with my FBO example https://blenderartists.org/forum/showthread.php?396018-FBO-hack-using-OpenGL-Wrapper-with-deferred-rendering-shader.
Actually I only get an black image. I think it is because I can't generate an empty texture glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width+viewport[0], height+viewport[1], 0, GL_RGBA, GL_UNSIGNED_BYTE, None) # I can't pass an empty pointer here.
But I don't get an error. So I think the other function calls are also working.

Tested:
glCheckFramebufferStatus
glGenFramebuffers
glBindFramebuffer
glFramebufferTexture2D
glGenRenderbuffers
glBindRenderbuffer
glRenderbufferStorage
glFramebufferRenderbuffer
glDrawBuffers
glDeleteFramebuffers
glDeleteFramebuffers

[panzergame]

Could you debug with apitrace or at least send a trace please ?

[HG1-Public]

The Api trace is not very use full here. The shortest call trace that I was to produce is 22 MB big https://www.dropbox.com/s/sl701v4h9xeu0b3/Framebuffer1.2.blend?dl=0.
And the error log only prints out only the default Blender OpenGL errors after start. If I run the script no new errors will be logged.

I am pretty sure that the black screen is no BGL related issue.

1. I don't changed Dalai's modifications.
2. I also get a black screen if I use the original version with in the UPBGE. So It must be some other issue. Looks like that it is caused by the shader (version 120, in/out problem).

[panzergame]

I got this result:

Is it what is wanted ?

[HG1-Public]

Ups. Wrong link. This was my test file (G-Buffer test).
Here is the link to the trace file https://www.dropbox.com/s/v77l9knlc28osmz/blender.6.trace?dl=0

Is it what is wanted ?

No. The final image should look like as the screenshot in https://blenderartists.org/forum/showthread.php?396018-FBO-hack-using-OpenGL-Wrapper-with-deferred-rendering-shader.

[HG1-Public]

The framebuffer calls are working. The issues are caused by the changes in the UPBGE (render timing and viewport).

1. Some changes in the shaders are needed because of the different openGL version.
2. The framebuffer now need to enabled in the pre_draw to get the images rendered.
3. If I enable the framebuffer the viewport will be drawn over the render plane (I moved it outside to see the rendering result).

[panzergame]

@HG1-Public : As i understand you want to bind a framebuffer to get the scene rendered to it ? If this is the case it should never works because we bind a FBO internally for rendering.

[HG1-Public]

As i understand you want to bind a framebuffer to get the scene rendered to it ?

Yes that is what this example will do.

Could you test again in master ? #post 7

I don't need to get this example working in UPBGE. I only used this example to test that the new API is working correct.

[panzergame]

Can i close this issue if all back to normal ?

[HG1-Public]

Yes. Can be closed.