I reformulated my problem because it evolves since the begin of my last thread:
I want to do a simple thing:
I have a simple texturedquad wich i write texcoords st to an RGBA image in RG components using this simple shader and render to texture:
uniform sampler2D unusedTexture;
void main(){
gl_FragColor=vec4(gl_TexCoord[0].st,0,1);
}
it gives me that
after that i modify my prog in order to take this image as input texture and modify the shader:
uniform sampler2D indexTexture; //texcoord texture
void main(){
vec4 pos = texture2D(indexTexture, gl_TexCoord[0].st); take
//first indirection: pos has expected values as i tried to output it
vec4 col= texture2D(indexTexture,pos.xy);
// second indirection: bad lookup output
}
What I want is the same image as inputTexture since i take pos in a texcoordtexture data that must be the same as gl_TexCoord[0].st
but the resulting render is:
can you help with this problem?
Is this a hardware problem or limitation ? ( I'm working with a Quadro1500M... :( )
