Comments on: 3. GLSL Coloring

By: CLundquist

CLundquist — Fri, 27 May 2011 04:55:54 +0000

Thanks for this! I was wondering why gl_Color was always 0,0,0,0 in my fragment shader. I didn’t realize it was interpolated from the vertex shader based on gl_FrontColor.

By: Swiftless

Swiftless — Fri, 20 May 2011 02:26:10 +0000

Hi Paras,

My guess would be that your shader isn’t loading correctly. Other than that, if the code is the same as the tutorial, it should work.

Thanks,
Swiftless

By: Swiftless

Swiftless — Fri, 20 May 2011 02:14:32 +0000

Hi Mr. What,

In the OpenGL 4 tutorials, I have named attributes which are sent to the shaders, however these don’t link to glVertex and glColor calls which have since been removed. They instead link to a VBO which stores the data.

In OpenGL 2.x and prior, glVertex and glColor calls were automatically mapped by OpenGL to GLSL variables gl_Color and gl_Vertex.

Cheers,
Swiftless

By: Paras

Paras — Thu, 19 May 2011 09:27:36 +0000

Hi Swiftless,

Every thing works great, but why am I seeing a White cube instead of a Red cube as set by glColor4f();

By: Mr.What

Mr.What — Wed, 04 May 2011 14:24:39 +0000

Finally, a tutorial which uses some old-school direct render calls, glVertex*, glColor*, with GL3 shaders!
This really solved my problem!

I agree with Steve, I’d like to see how to write and use a shader that works with direct glVertex*, glColor*, but does not use compatibility profile attribute variables.
I’d like to see how I could attach glVertex* and glColor* to some named attribute in a GLSL shader.

By: Swiftless

Swiftless — Sun, 31 Oct 2010 21:17:38 +0000

Hey Steve,

I think you might want to check out the OpenGL 4 tutorials mate

Cheers,
Swiftless

By: Steve

Steve — Sun, 31 Oct 2010 19:12:43 +0000

hm – all tutorials i read so far are using compatibility profile.
Build ins like gl_Color, gl_ModelViewProjectionMatrix, gl_Vertex … are all deprecated and removed in core profiles. I would appreciate it to read tutorials for core-profiles, not for compatibility profile using deprecated variables and functions.