OpenGL GLSL Gouraud Shading

This is a demo of the fixed-pipeline Gouraud shading. Check out Blinn-Phong and Phong shading models to compare!

Category:

Science & Technology

Tags:

• OpenGL
• GLSL
• Gouraud
• Shading

[PJS305]

good video.

how long did this take to create and how did you make it?

[OrigonWaltz]

Making this is pretty straigthforward using OpenGL since the shade model GL_SMOOTH is actually a Gouraud shading.

However, Phong and Blinn-Phong shading models in my other videos require per-fragment calculations which can only be done with a shader.

[SuperFeimer]

@OrigonWaltz not true, OpenGL does not have native support for gourade shading.

[OrigonWaltz]

@SuperFeimer Yes it does. When you use GL_SMOOTH, you basically ask OpenGL to do a Gouraud shading. I'm pretty sure I'm not wrong here. Give us a reference if you still think you are right please, I'll be pleased to correct myself!

[polvoazul]

@cplusplusish Its beatiful to see a peacefull discussion in youtube for a change! heheheh

[jnbolito]

@OrigonWaltz Technically speaking, OpenGL does not support Gouraud shading directly with the snap of your fingers. It simply uses a more general method called smooth (or interpolative) shading in which it interpolates colours between vertex normals. It does not calculate normals for you! That's up to you and that's why it can't be called Gouraud shading. If you compute a vertex normal as the normalised sum of all the vertex normals shared by a particular vertex, you get Gouraud shading.

[cplusplusish]

@OrigonWaltz I am also SuperFeimer. You're completely correct, I'm sorry. Back then I misunderstood what gouraud shading was, for some strange reason I was under the impression that gouraud shading was something different to what you said.

I feel so stupid, of course OpenGL supports gourard shading!