1D Texture Coordinates

[PickleWorld]

I am having some problems accessing 1D texture coordinates in a fragment program. I am using a very simple program to test it…

Vertex Program calls…
gl_TexCoord[0] = gl_MultiTexCoord0;
gl_Position = ftransform();

Fragment Programs calls…
vec3 finalColor = vec3(gl_TexCoord[0].s, 0.0, 0.0);
gl_FragColor = vec4(finalColor, 1.0);

If I use gl_TexCoord[0].s I get black, if I use gl_TexCoord[0].t I get red (ie 0 and 1). Am I doing something wrong?

p.s. my texture coordinates work fine in fixed pipeline.

[imported_CRasterImag]

I haven’t used a 1D texture before, but I am pretty sure you need a sampler variable of some kind.

[zeoverlord]

Two questions

1. what UV coordinates did you set
2. did you set any uv coordinates before that.

[imported_Budric]

Did you set the texture coordinates on your primitive correctly via glTexCoord1d(s); ?

[PaladinOfKaos]

I don’t see a sampler - you’re just converting the texture coordinates to a color. You’ll need to add a sampler uniform, and initialize it from your C code:

VERTEX:
void main()
{
   gl_TexCoord[0] = gl_MultiTexCoord0;
   gl_Position = ftransform();
}

FRAGMENT:
uniform sampler1D my_sampler;

void main()
{
   gl_FragColor = vec4(texture1D(my_sampler, gl_TexCoord[0].s).rgb, 1.0f);
}

In your application, you’ll have to pass the texture ID into the sampler uniform:

glUseProgram(program);
GLint sampler_location = glGetUniformLocation(program, "my_sampler");
glUniform1i(sampler_location, texture_id);