arb vertex program not working

OpenGL OpenGL: Advanced Coding
1

Hello,

I have just begun experimenting with the arb vertex program in order to see how they work.

I am simply trying to pass a float in to the program and use it to shrink/grow a quad…the float varies from 0.5 to 2.0. over time in 0.05 increments.

const char EXPANDTEST[]= “!!ARBvp1.0
ATTRIB iPos = vertex.position;
ATTRIB iNormal = vertex.normal;
ATTRIB iColor = vertex.color;
ATTRIB iTex = vertex.texcoord;
ATTRIB iTex1 = vertex.texcoord[1];
PARAM mfactor = program.env[0];
PARAM mvp[4] = { state.matrix.mvp };
PARAM mvpinv[4]={ state.matrix.modelview.invtrans};
PARAM lightdir = state.light[0].position;
PARAM halfdir = state.light[0].half;
PARAM specexp = state.material.shininess;
PARAM ambientcol = state.lightprod[0].ambient;
PARAM diffusecol = state.lightprod[0].diffuse;
PARAM speccol = state.lightprod[0].specular;
OUTPUT oPos = result.position;
OUTPUT oColor = result.color;
OUTPUT oTex = result.texcoord;
OUTPUT oTex1 = result.texcoord[1];
TEMP xfnorm;
TEMP temp;
TEMP dots;
TEMP res;
TEMP tpos;

MUL tpos,mfactor,iPos;\ BLING BLING!
DP4 oPos.x, mvp[0], tpos;
DP4 oPos.y, mvp[1], tpos;
DP4 oPos.z, mvp[2], tpos;
DP4 oPos.w, mvp[3], tpos;

DP3 xfnorm.x, mvpinv[0],iNormal;
DP3 xfnorm.y, mvpinv[1],iNormal;
DP3 xfnorm.z, mvpinv[2],iNormal;
DP3 res.w, xfnorm,xfnorm;
RSQ res.w,res.w;
MUL res.xyz,res.w,xfnorm;
MOV xfnorm,res;
DP3 dots.x, xfnorm, lightdir;
DP3 dots.y, xfnorm, halfdir;
MOV dots.w, specexp.x;
LIT dots,dots;
MAD temp,dots.y,diffusecol,ambientcol;
MAD oColor.xyz,dots.z,speccol,temp;

MOV oColor.w,diffusecol.w;
MOV oTex, iTex;
MOV oTex1, iTex1;
END”;

I see no effect on the quad. I also tried simply multiplying the position by a constant directly:
ie changed:
MUL tpos,mfactor,iPos;
to
MUL tpos,2.0,iPos;
and it didnt work
although if i changed the 2.0 to 0.0 i see nothing…which makes sense.

There are no errors reported either by glGetString(GL_PROGRAM_ERROR_STRING_ARB)
or
glGetError()

Any idea why it wouldnt work?

Thanks,

Jeremy

2

You might want to end your lines with
\ not just . I’m not sure why you aren’t getting an error, but as I read what you wrote, OpenGL is seeing a big one-line string with no newlines in it.

3

nope, no workie!

Just to clarify, i see the textured quad, but dont see it changing like i want.

4

Originally posted by bumby:
I see no effect on the quad. I also tried simply multiplying the position by a constant directly:
ie changed:
MUL tpos,mfactor,iPos;
to
MUL tpos,2.0,iPos;
and it didnt work
Shouldn’t work :wink:
You multiply all four components of the source vector by two. Later, perspective divides divides x, y and z by w. cx/(cw)=x/w for all c!=0, if you catch my drift.

although if i changed the 2.0 to 0.0 i see nothing…which makes sense.
Absolutely :slight_smile:

Try your first shader and this:

float bling[4]={2.0f,2.0f,2.0f,1.0f};
glProgramEnvParameter4fvARB(GL_VERTEX_PROGRAM_ARB,0,bling);
5

Criminy!

That was it!

Thanks a billion!