OpenGL shader examples

[pestery]

Hi all. I've made a couple of OpenGL shader examples. One is a simple triangle on the screen example. The other is 3D and uses a maths library I've been building (also included). I've put comments and labels everywhere to try and explain everything. I don't think I've used any depreciated OpenGL functions (I tried not too).

One thing I should mention is that the examples required OpenGL 2.0 or above. I know some on the forum are running older hardware so its worth mentioning.

Anyway, here's the download link, http://www.mediafire.com/file/wlrwrro93 ... Shader.zip

Also, this is a webpage that I found very useful. It has a really good explanation of everything shaders, and its also up to date. When I was searching for shader info and examples most of what I could find was useful, but out of data (used depreciated function, etc). http://duriansoftware.com/joe/An-intro- ... tents.html

[Aave]

Great to see some newer OpenGL examples. Extra points for using VBOs and going beyond the old OpenGL 2.0 and using GLSL from OpenGL 3.1 (note for people with 2.0 only: see the readme).

EDIT: Examples run fine on Linux, but I needed to add a definition of NULL to shader.bi:

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#Ifndef NULL
#Define NULL 0
#EndIf

[podvornyak]

Damn good Pestery!

EDIT: Examples run fine on Linux, but I needed to add a definition of NULL to shader.bi:

or incode constant

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const NULL = 0

[pestery]

Glad you like it :-)

I've updated the original link. I've added the #define NULL as suggested by Aave. I've also slightly updated the maths.bas file, and added a my standard image loader thingy.

And, test3 now exists! Uses textures and blending. Enjoy.

[joseywales72]

Thanks for the examples. They are very useful.
There is something wrong with test3 though. It gives this when I try to compile.

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/usr/include/freebasic/crt/sys/linux/types.bi(96) error 4: Duplicated definition in 'type int64_t as integer'

I'm on Archlinux. The other examples compile and run fine.
Thanks again.
Anil

[podvornyak]

At ubuntu 10.04 64 with 0.22 work fine.

[pestery]

Hi Anil. I've fixed the bug so it should work now. The bug was actually in my OpenGL headers, which I guess your using :-)

I've updated the download link in the other post. Thanks for letting me know.
http://www.freebasic.net/forum/viewtopi ... highlight=

[joseywales72]

I downloaded and set up your updated headers and everything is ok now. Thank you for the fix and most importantly for the headers themselves.

[pestery]

Hi all. Back again with another update of the examples.

I noticed a bug in my maths library that I'd bundled with the shader examples. I've tested this new version a lot and I'm pretty sure its bug free. Its also a lot longer because I've added a heap on new datatypes, functions and operators.

If anyone is using the bundled API files for FbEdit then I've updated those too. I added some stuff for framebuffer object functions. Also made a couple of small changes to the existing examples to make them automatically select the shader files.

Lastly, I've added a forth example which has a nice glow effect. The example also uses framebuffer objects as well, though because they are only available in GL 3.0 there are also fallback commands in the example. I've tested it and it runs fine on both GL 2.1 and GL 4.2.

Enjoy :-)

[Aave]

I get compile error form all tests:

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OpenGL_Shader/inc/shader.bi(282) error 41: Variable not declared, GL_MAX_COLOR_ATTACHMENTS in 'glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS, @opengl_info.fbo_attach)'

If I hard code that into an arbitrary value, I can build and run tests 1-3. However test 4 gives:

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test4.bas(496) error 41: Variable not declared, GL_RENDERBUFFER in 'glBindRenderbuffer(GL_RENDERBUFFER, .fbo_depth)'
test4.bas(502) error 41: Variable not declared, GL_FRAMEBUFFER in 'glBindFramebuffer(GL_FRAMEBUFFER, .fbo)'
test4.bas(506) error 41: Variable not declared, GL_COLOR_ATTACHMENT0 in 'glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, .texture[i], 0)'
test4.bas(510) error 41: Variable not declared, GL_DEPTH_ATTACHMENT in 'glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, .fbo_depth)'
test4.bas(514) error 41: Variable not declared, GL_FRAMEBUFFER_COMPLETE in 'If check <> GL_FRAMEBUFFER_COMPLETE Then'
test4.bas(598) error 41: Variable not declared, GL_COLOR_ATTACHMENT1 in 'Dim As GLenum drawbuf(0 To 1) = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1}'
test4.bas(696) error 41: Variable not declared, GL_COLOR_ATTACHMENT2 in 'glDrawBuffer GL_COLOR_ATTACHMENT2'

One other thing, it would be nice if you could name the bas and dir differently, e.g. test1.bas and test1-data. This is because on linux, exes don't generally have any suffix (.exe), so if I command: fbc test1.bas, it won't work as it tries to create and exe named 'test1' but there's already a directory by that name. Of course I can work around this with fbc test1.bas -x test1exe, but it's slightly annoying.

[pestery]

Thanks for letting me know Aave. I've fixed up the folder names to make it easier on Linux. I've also added a bit to make sure those constants get defined if they are not present. I think I got them all :-)

Regarding the constants not being defined, you might want to get the updated version of glext.bi that I did a while ago. Using it should stop any other problems with things not being defined. http://www.freebasic.net/forum/viewtopi ... highlight=

[Aave]

I've also added a bit to make sure those constants get defined if they are not present. I think I got them all :-)

Not quite :P

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test4.bas(510) error 41: Variable not declared, GL_DEPTH_ATTACHMENT in 'glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, .fbo_depth)'
test4.bas(514) error 41: Variable not declared, GL_FRAMEBUFFER_COMPLETE in 'If check <> GL_FRAMEBUFFER_COMPLETE Then'

However, I did as you suggested and downloaded updated gl headers and was able to compile it.