hi everybody!
im experimenting with some camera tracking and want to make a water surface, that is triggering waves where motion is detected.
i found an old patch wich makes displacement according to a greyscale image so i build a little machine in a gemframebuffer that casts waves and feed it to the glsl displacement shader wich works good.
now here is my problem:
i want to display a separate image on the geometry distorted by glsl shader.
but i have no idea how to modify the shader so i can feed her 2 textures
can somebody help me?

http://www.pdpatchrepo.info/hurleur/GLSL_displacement.zip

so basically i want to use one texture for the displacement, wich happens in the vertex shader
and another for the color, wich happens in the fragment shader.

i have no idea, if its possible to feed a gemchain 2 textures, so a workaround i could imagine is to have the 2 textures merged side by side on one, and taking them apart again by using texture coordinates.

///vertex shader

uniform float K;
uniform vec4 translate;
uniform sampler2D tex0;

void main()

{

gl_TexCoord[0] = gl_MultiTexCoord0;

vec4 color = texture2D(tex0,gl_TexCoord[0].st);
float x = (color.r+color.g+color.b)/3.;
gl_Position = gl_ModelViewProjectionMatrix * (gl_Vertex + vec4(0.,0.,x,0));

}

///fragment shader // Cyrille Henry 2007

uniform sampler2D tex0; /// here tex1 should be used somehow..?

void main()
{
vec2 C = gl_TexCoord[0].st;
gl_FragColor = texture2D(tex0, C); /// here tex1 should be used somehow..?
}

you can find a solution for GLSL multitexture in this help patch:
GEM -> Examples -> 10.glsl/ > 05.multitexture.pd

hope this helps.
it's not straightforward to me, but should work.

and if you have a spare moment please give me feedback on this
http://puredata.hurleur.com/sujet-5000-collection-glsl-effects

thanks!

thanks a lot guido!
i will come back to you on your topic after that chrismasmadness is over.