us-east-1

shater vert and frag example

BlitzMax Forums/OpenGL Module/shater vert and frag example

Chris C(Posted 2005) [#1]
tom speed made a nice file to help with shaders so I had a twiddle with it, had to change a few bits because of how bmax has progressed recently

heres the results of my experiments, I hope you find it useful.

test.frag

test.vert

shadertest.bmx

tom speeds modifield glsl.bmx



Tom(Posted 2005) [#2]
Shaders are the future! :)


Chris C(Posted 2005) [#3]
lol that is *so* you!

getting the effect you want with glsl can be quite the challenge sometimes tho!


Tom(Posted 2005) [#4]
Yup, the language takes some getting used to, but is definately worth learning. It'll be interesting to see how much the max 3D module uses them, Mark's said it'll likely be 'shader centric'.


deps(Posted 2005) [#5]
This crashes for me in OSX 10.3.9. Is the integrated gaphics card (radeon 9200) too old for this?


Edit:
This is what I find in the "Output" tab:

I also get an OSX crash window.


Chris C(Posted 2005) [#6]
hmm, not sure about radeons, try out test.frag and test.vert with some kind of mac shader editor could you?


deps(Posted 2005) [#7]
OSX xtools comes with a simple shader editor but it looks like it doesn't support glsl. And I cannot find any other shader editor for osx. :/


Chris C(Posted 2005) [#8]
will this work http://www.macinit.com/mifx/index.html

I'd like to get together a simple set of shaders that will work on craptastic (and common) cards like my fx5200 and for that matter your radeon 9200

I've added some animation to both the frag and vert shader, but theres not too much point if I cant get it to work

can you increase the size of the compilers log
Global clog:Byte[1024]
to say 4096 bytes and change
all the
glGetInfoLogARB(Program,1023,Varptr slen, Varptr clog[0])
commands to
glGetInfoLogARB(Program,4095,Varptr slen, Varptr clog[0])

just to see if we have all the output from your cards shader compiler...


deps(Posted 2005) [#9]
cannot compile mifx, it needs xtools 2 and I can only use 1.5 since I'm using osx 10.3.9.

I did the changes to glsl.bmx but nothing new was printed in the output tab. And it still crashes.


Hotcakes(Posted 2005) [#10]
I thought xtools 2.2 was 10.4 only, but 2.1 was fine?


Chris C(Posted 2005) [#11]
well unless someone with a radeon 9200 and a *working* shader editor can give me a little more feedback, I have no clue as to whats wrong, I can send you a simpler shader if your interested...


DH(Posted 2005) [#12]
anyone got a screen shot of the above code in action?


Tom(Posted 2005) [#13]
You all have OpenGL v1.5+ drivers? Pretty sure that's what's needed for GLSL


joncom2000(Posted 2005) [#14]
Wasn't the Radeon 9200 a shader version 1 card, I suspect as Tom says it could be a driver problem or perhaps the shader up there using Version 2 functions ?


JoshK(Posted 2007) [#15]
Testing with a Radeon 9550. glCreateProgramObjectARB() fails.

My guess is something in glew.mod is screwed up.


JoshK(Posted 2007) [#16]
I determined this happens because ATI cards actually return a long-ass negative number (an unsigned integer).

Now I have to figure out how to convert this into something OpenGL can recognize as a UINT.


JoshK(Posted 2007) [#17]
I fixed it so it will work with ATI cards.

-vPosition is declared as a vec2 then as a vec3. Change them both to vec3.

-In glsl.bmx, change this:
		'Create a new GL ProgramObject
		p.Program = glCreateProgramObjectARB()
		If p.Program<1

to this:
		'Create a new GL ProgramObject
		p.Program = glCreateProgramObjectARB()
		If p.Program=0



cr(Posted 2010) [#18]
.


SLotman(Posted 2010) [#19]
Just tried here on ATI x1300, which is shader model 3.0 - nothing happens when I click the left mouse, and on output window I get the following:

Compiled: test.vert successfuly in 6ms

Compiled: test.frag successfuly in 5ms

VertexShader test.vert attached & linked ok!


Failed to link FragShader 'test.frag'

Fragment shader(s) failed to link,  vertex shader(s) failed to link. 

Error getting Uniform Var Location 'color' in Method setUF4

Process terminated


Edit: apparently this is the line that causes trouble in the frag. shader:

vec2 fp=fract(4.0 * vPosition.xy);


I don't know why, never did anything shader-related :P

Having the frag shader as this, it works (I get an orange flashing mesh, deformed):
uniform vec4 color;

varying vec2 vPosition;
varying vec3 vNormal;


void main(void)
{

   float diffuse = 0.3 + 0.5 * dot(vNormal.xy, vNormal.xy);
   gl_FragColor = color * diffuse;
}


Last edited 2010


col(Posted 2010) [#20]
varying vec2 vPosition;

should be

varying vec3 vPosition;

the vertex program and fragment program varyings should be the same. ie Its declared as vec3 in the frag shader, so it should match in the vertex shader.
This fix is actually in a previous post above :)