Cool demo with ZGE-conversion

[y offs et]

Well, I tried a few things with no change. I'm pretty green at shaders. A better approach for me would be to try to construct the simplest shader from scratch.

The stock shader example works fine.

Any examples?

[Kjell]

Hi,

Could you please try the attached source containing 4 stages of a Lava-ish shader? Just change the Material to use the different shaders and let me know at what stage it fails ( if at all ).

K

[y offs et]

I re-saved as Lava1 with shader none selected.

When loading any zgeproj, virtually every one has some log message after the loading line. However, none appears here, which makes me suspect it never finishes loading. However, after 10 minutes...

Loaded with shader none selected in material - click App - start preview - no problem

select shader1 - on click app - this

#Error in Vertex shader compilation
#Fragment shader compiled OK
#Error when linking shader program
#Error when linking shader program

select none - click - start to move log readout some

select shader2 - on click app - this

#Error in Vertex shader compilation
+GL ERROR: 1282
#Fragment shader compiled OK
#Error when linking shader program
#Error when linking shader program
#Shader variable error:time

select none - click - start to move log readout some

select shader3 - on click app - this

#Error in Vertex shader compilation
+GL ERROR: 1282
#Fragment shader compiled OK
#Error when linking shader program
#Error when linking shader program
#Shader variable error:time

select none - click - start to move log readout some

select shader4 - on click app - this

#Error in Vertex shader compilation
+GL ERROR: 1282
#Fragment shader compiled OK
#Error when linking shader program
#Error when linking shader program
#Shader variable error:time


There's something going on behind because on click start,

there is about 7-15 seconds (lower to higher number shader) from when

+Gamepads detected:0

until

*Models:0

starts streaming at it's usual 1 sec interval.

...and, of course, there is no display of any kind except for a white square.

Not much help I'm afraid.

[Kjell]

On the contrary, these results are quite unexpected and might be allot more useful then when everything would work. Here are 4 more basic shaders that result in a green rectangle ( in various sizes ) when they work correctly.

Hopefully this will narrow the scope down a bit

K

[y offs et]

When loading any zgeproj, virtually every one has some log message after the loading line. However, none appears here, which makes me suspect it never finishes loading. However, after 1 minutes...

Loaded with shader none selected in material - click App - start preview - no problem

select shader1 - on click app - this

start
works!

select shader2 - on click app - this

start
works!

select shader3 - on click app - this

#Error in Vertex shader compilation
#Fragment shader compiled OK

start
dunno - got a green box like shader1
no more error messages

note - here I decided to go back to the beginning and click/start with <none> as my way of clearing after each trial. Worked thru list again.

Results the same except shader3 gave no error messages and ran with a white box - strange


select none - click - start to move log readout some

select shader4 - on click app - this

start
works!
full green screen



There's something still going on behind because on click start,

there is a longer wait (lower to higher number shader) from when

+Gamepads detected:0

until

*Models:0

starts streaming at it's usual 1 sec interval.

The more trials I did the longer (30 sec-last) as if some calculations are accumulating. I couldn't see a memory leak watching my meter.

[Kjell]

Ok,

That actually makes sense, gl_Vertex is a read-only attribute .. so ATI respects the specification more strict then NVIDIA does. Could you try the Lava shaders one more time with the following line removed from all the vertex shaders, to see if it makes any difference?

Code: Select all

gl_Vertex.xy *= 2;

My guess is that at least the first Lava shader will work then.

Thanks ~
K

[y offs et]

Lava1 - code commented.

When loading any zgeproj, virtually every one has some log message after the loading line. However, none appears here, which makes me suspect it never finishes loading. However, after 1 minutes...

Loaded with shader none selected in material - click App - start preview - no problem

select shader1 - on click app - this

start
works!
nice gradient

select none - click - start to move log readout some

select shader2 - on click app - this

start
works!
oohh! pretty moving gradient!

select none - click - start to move log readout some

select shader3 - on click app - this

start
works!
ooohhh! getting rolled over by a rainbw ball!

select none - click - start to move log readout some

select shader4 - on click app - this

start
works!
oohh! the oily blob with the rainbow skin



There's something still going on behind because on click start,

there is a longer wait (lower to higher number shader) from when

+Gamepads detected:0

until

*Models:0

starts streaming at it's usual 1 sec interval.

There's still some data accumulation going on. Something isn't nil'ing.

[VilleK]

New article on the same blog: http://sizecoding.blogspot.com/2009/11/ ... k-for.html

He has made a new version of the shader that is supposed to work better on ATI.

Set FragmentShaderSource to this:

Code: Select all

uniform float w;

float o(vec3 p){return min(
cos(p.x)+cos(p.y)+cos(p.z)+cos(p.y*20)*.02,
length(max(abs(p-vec3(cos(p.z)*.2,cos(p.z)*.2-.5,0))-vec3(.2,.02,w+3),vec3(0)))
);}

vec3 n(vec3 p){return normalize(vec3(o(p+vec3(.02,0,0)),o(p+vec3(0,.02,0)),o(p+vec3(0,0,.02))));}

void main(){
vec3 s=vec3(cos(w),-cos(w*.5)*.5+.5,w);
vec3 e=normalize(vec3(gl_FragCoord.xy*.002-1,1));
vec3 p=s;
for(int i=0;i<55;i++)p+=e*o(p);
vec3 pp=p+=e=reflect(e,n(p));
for(int i=0;i<55;i++)p+=e*o(p);
gl_FragColor=abs(dot(n(p),vec3(.1)))+vec4(.2,cos(w*.5)*.5+.5,sin(w*.5)*.5+.5,1)*length(p-s)*.01
+length(p-s)*.01+(1-min(pp.y+2,1.))*vec4(1,.8,.7,1);
}

[y offs et]

tried it.
same result

[Kjell]

Guess it was the read-only thing that caused the problem for all Lava shaders. Well, at least we now know the problem doesn't lie within the features used in the tests so far. I'll get back with another test-case using more techniques from the tunnel & ribbon shader.

I do actually wonder whether something like vec3(1) is officially supported ... opposed to vec3(1,1,1).

K

[VilleK]

Perhaps it's possible to write a entire game with a shader . Just process the input from the main program and set it to uniform variables. The demo-shader should be pretty simple to modify so that you can move around using mouse or cursor keys.

[Kjell]

Sure it would be possible, but it wouldn't make any sense writing your own complete GLSL-based render-engine ... unless you want to use something that's completely different from polygons / voxels / nurbs ( through a extension ). But in that case it's probably a better idea to side-step OpenGL altogether ( plus there's no cheap way to manage objects within a shader )

K