Toon shader, improvements?

[serengeor]

Ok so I found a shader that got integrated without too much of an effort.
And I would like to know what could be improved

Heres .frag:

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varying vec3 normal;
varying vec3 ec_pos;

void main()
{
	vec4 color = vec4(0.3, 0.7, 1.0, 1.0);
	
	vec3 light = vec3( gl_LightSource[0].position );
	vec3 lightdir = light - ec_pos;
	vec3 reflectVec = normalize(reflect( -lightdir, normal ));
	vec3 viewVec = normalize( -ec_pos );
	//Diffuse intensity
	float diff = max( dot(normalize(lightdir), normalize(normal)), 0.0);
	//Specular intensity
	float spec = 0.0;
	
	//Specular intensity
	if (diff > 0.0)
	{
		spec = max(dot(reflectVec, viewVec), 0.0);
		//The specular highlight only gets smaller when
		//raised to some power.
		//Leaving it out gives a nice big highlight.
		spec = pow(spec,16);
	}
	
	diff =  diff * 0.8 + spec * 0.4;
	
	//Diffuse intensity
	if (diff > 0.90)
		diff = 1.5;
	else if (diff > 0.7)
		diff = 1.2;
	else if (diff > 0.5)
		diff = 0.9;
	else 
		diff = 0.5;
	
	gl_FragColor = color * diff;
}

Heres .vert:

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//Interpolates the vertex normal across the texture fragment
varying vec3 normal;
//Interpolate the texel position in eye space.
varying vec3 ec_pos;

void main()
{
	normal = gl_NormalMatrix * gl_Normal;
	ec_pos = gl_ModelViewMatrix * gl_Vertex;
	
	//Perform fixed transformation for the vertex
	gl_Position = ftransform();		
}

Heres how it looks when integrated into shaders sample:


PS. I'm currently just toying around with shaders.

[Radikalizm]

Do you maybe have some more complex models to apply the shader to?
A sphere doesn't give a good impression of what the shader can do, nor what can be optimized/changed about it

[serengeor]

Do you maybe have some more complex models to apply the shader to?
A sphere doesn't give a good impression of what the shader can do, nor what can be optimized/changed about it

Okay, will post it in a minute or two.
EDIT: Heres a teapot using the shader:




Do you need more detailed mesh, or is this enough?

[Mel]

You can do it light dependant, and you can add also code to create the borders, though that can be very tricky.

To add borders you can duplicate the mesh, shift the vertices a bit in the normal's direction and then flip the triangle's normals in order to have a shell over the original mesh that will draw the outlines. This approach, for instance, is used here:

[ent1ty]

Wouldn't be edge-detection shader better? Sure, it would require another render pass, but your option basically does too.

[Radikalizm]

I'd go for an edge-detection solution too instead of redrawing the geometry, although I don't know how much of a performance gain this would give over redrawing in a forward renderer (would be perfect for a deferred renderer though)

[Mel]

There would be very little impact on the performance, compared to an edge detection shader.

Duplicating the amount of polygons represents very little overhead with that kind of rendering (i am not speaking of skinned meshes, though, only static). Besides, drawing the outlines after the first render would cull almost completely the second mesh. The gain is little, though, but the borders are perfect, can't be easily matched by a edge detection shader. And would enjoy MSAA, for instance.

[Radikalizm]

There would be very little impact on the performance, compared to an edge detection shader.

Duplicating the amount of polygons represents very little overhead with that kind of rendering (i am not speaking of skinned meshes, though, only static). Besides, drawing the outlines after the first render would cull almost completely the second mesh. The gain is little, though, but the borders are perfect, can't be easily matched by a edge detection shader. And would enjoy MSAA, for instance.

You're probably right, I'm always thinking in a deferred context these days, and deferred it's just a matter of a rather simple post-processing effect to achieve perfect edge detection

[devsh]

you could anti-alias your boundaries

instead of

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if (col>0.6)
   col = 1.0;
else if (col>0.3)
   col = 0.6;
else
   col = 0.0;

use

min((x+0.7)^128,0.6)+min((x+0.4)^128,0.4)

which should be waaaay faster because of branching (ewww control statements in shaders)

[Radikalizm]

(ewww control statements in shaders)

I can agree with you that these weren't needed in this case, but no need to generalize, most of the time you can't really do without them

[serengeor]

Thank you all.
I'd love to have borders but, wouldn't it cost too much if I'd make my all level with borders?(tough it wouldn't be too much of poly's as my levels would be made from simple geometries).
And I'm not really good at shaders, only started yesterday, so you know

How would I actually use that:

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min((x+0.7)^128,0.6)+min((x+0.4)^128,0.4) 

I'll look up glsl cheat sheet, and look if I can figure it out.

[Mel]

The levels can be designed with textures with borders, or you could always draw the level textures using toon style, but no toon shader at all. The good thing of the levels in toon style is that they don't need accurate lighting. That is done in many of the Dragon Ball fighting games for PS2, perhaps.

(images > 1000 words )

[serengeor]

New pic with mel's suggestion:

[Mel]

Looks quite nice. although the model should have a uniform outline though it is a really interesting toon shader.

[ent1ty]

I actually like this more than the uniform outline style