5th texture displays fine in window, on FBO not

[Ftored]

Hello,

I am relatively new to openGl and GPGPU. I am trying to implement an algorithm which needs input for 5 or more texture images to calculate the result.

I have this small problem. I use 5 textures for my input in a GPGPU computation. If i render the each texture using the shader like gl_gl_FragColor=(texture5,1) it shows just fine.

But if i use fbo i get a -1#INF. I though that the problem using more than 4 textures on a FBO was if you used attachmentpoints not binding the with uniform variables like this:

glActiveTexture(GL_TEXTURE4);
glBindTexture( GL_TEXTURE_2D, texture5 );
texLoc = glGetUniformLocation(ShaderProgram, "tex5");
glUniform1i(texLoc, 4);

Anyone can shed some light? It would be really appreciated.
Thanks in advance

[-NiCo-]

"gl_gl_FragColor=(texture5,1)"

That doesn't look like valid GLSL syntax to me...
Did you validate your FBO before rendering to it?

[Ftored]

Yes. I check if it works ok every step, and it says it is complete. Sorry i was not good at copy paste with that part.. I have : gl_FragColor = vec4 (texture5,1); where avg is the float value i need back.

The weird is that on screen its ok, but on fbo it gives me that value back. SO it should work. I ll recheck the whole process of creating and binding the fbo.

[-NiCo-]

What kind of graphics card are you using? Maybe the card only has 4 texture units and this problem doesn't show up if you draw them one by one. Can you post the fragment shader, FBO setup and rendering call?

[Ftored]

I use 7600GT. But if i draw it on screen it works ok..why it wouldnt work if it was drawn on fbo? The code is:

Fragment shader (i deleted most of the stuff and just left it to return the texture5, i checked and the problem again is there)

uniform sampler2D tex;
uniform sampler2D tex2;
uniform sampler2D tex3;
uniform sampler2D tex4;
uniform sampler2D tex5;
 
uniform float Threshold;
uniform float WashInStart;
uniform float WashInPoints;
 
varying vec2  TexCoord; 
 
void main(void)
{
    float dectimeStart=0.0180;
	float dectime=0.0120;
  	vec3 A = (0.1,0.0,0.0);
    float enchant=0.0;
    float mVal=0.0;
	float LocalWashInStart=0.0;
	float Delay=0.0;
	float EarlyStart=0.0;
	float EarlyFinish=0.0;
	float EarlyEnchancementAvg=0.0;
 
 
    vec3 textureColor1  =texture2D(tex, TexCoord).rgb;
    vec3 textureColor2 = texture2D(tex2,TexCoord).rgb;
    vec3 textureColor3 = texture2D(tex3,TexCoord).rgb;
    vec3 textureColor4 = texture2D(tex4,TexCoord).rgb;
    vec3 textureColor5 = texture2D(tex5,TexCoord).rgb;
 
	float tmp=textureColor5.r;
	gl_FragColor = vec4 (tmp,0.0,0.0,1.0);
 
}

The code for FBO is:
(This works for every texture except 5 )

// Set up the viewport for 1:1 pixel to texel mapping
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0, size , 0.0, size);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glViewport(0, 0, size, size); 
 
 
	//FBO creation
	GLuint fbo;
	glGenFramebuffersEXT(1, &fbo);
	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
	glReadBuffer(GL_COLOR_ATTACHMENT0_EXT); 
	checkGLErrors("FBO creation or Binding");
	checkFramebufferStatus();
 
 
 
	//Setup output texture
	GLuint img;
	glGenTextures(1, &img);
	glBindTexture(GL_TEXTURE_2D, img);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB16F_ARB,  size, size, 0, GL_RED, GL_UNSIGNED_BYTE, NULL);
	glTexSubImage2D(GL_TEXTURE_2D,0,0,0,size,size,GL_RED,GL_FLOAT,data);
 
	glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, img, 0);
	checkFramebufferStatus();	
	checkGLErrors("Output Texture Creation");
 
 
 
	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
  	checkGLErrors("Frame Buffer binding");
	checkFramebufferStatus();
 
	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT); 
	glPolygonMode(GL_FRONT, GL_FILL); 
	glBegin( GL_QUADS );
	    glTexCoord2f(0.0, 1.0); 
		glVertex2f(0.0, 0.0);
		glTexCoord2f(1.0, 1.0); 
		glVertex2f(size, 0.0);
		glTexCoord2f(1.0, 0.0);
		glVertex2f(size, size);
		glTexCoord2f(0.0, 0.0); 
		glVertex2f(0.0, size);
	glEnd();
 
	checkFramebufferStatus();
	checkGLErrors("Render to FBO");
 
	//Reading values from frameBuffer to array with flaots
	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
	glReadPixels(0, 0, size, size,GL_RED,GL_FLOAT,pixels);
 
 
 
	writeFile("Output1.dat",data,size);
	printVector(data,1024*1024);
 
	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
	checkGLErrors("Frame Buffer unbinding");
 
	glDeleteTextures(1,&img);
 
	glActiveTexture(GL_TEXTURE0);	
	glBindTexture( GL_TEXTURE_2D, texture1 );
 
	glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0,size,0.0,size);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glViewport(0,0,size,size);
 
	glTranslatef(0.0,0.0,-24); // We move the object 24 points forward to fill the window
	glBegin( GL_QUADS );
	{
	  glTexCoord2f(0.0, 0.0); 
		glVertex2f(0.0, 0.0);
		glTexCoord2f(1.0, 0.0); 
		glVertex2f(size, 0.0);
		glTexCoord2f(1.0, 1.0);
		glVertex2f(size, size);
		glTexCoord2f(0.0, 1.0); 
		glVertex2f(0.0, size);
	}
	glEnd();
 
 
 
	glDeleteFramebuffersEXT(1, &fbo);
	free(data);
	glUseProgram(0);
        checkGLErrors("Render on Screen");
	exit(1);

You see something that may lead to this? I now that the code may have a lot of problems but i am new to this.:$

[-NiCo-]

At first sight I don't see anythingw rong with the code except for the fact that you probably meant to write

//Reading values from frameBuffer to array with flaots
glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
glReadPixels(0, 0, size, size,GL_RED,GL_FLOAT,pixels);

instead of

//Reading values from frameBuffer to array with flaots
glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
glReadPixels(0, 0, size, size,GL_RED,GL_FLOAT,pixels);

Are you sure you set up texture5 the same way you did the others?

[Ftored]

I call the same function to create and setup each texture. I never undestood though why i have to use glActiveTexture(GL_TEXTURE0);
And i mean TEXTURE0 means is the 1st it was setup? And TEXTURE1 the second? And just go on?


This is the code where i bind the uniform variables-textures to shader

        glActiveTexture(GL_TEXTURE0);	
	glBindTexture( GL_TEXTURE_2D, texture1 );
	texLoc = glGetUniformLocation(ShaderProgram, "tex1");
	glUniform1i(texLoc, 0);
 
	glActiveTexture(GL_TEXTURE1);	
	glBindTexture( GL_TEXTURE_2D, texture2 );
	texLoc = glGetUniformLocation(ShaderProgram, "tex2");
	glUniform1i(texLoc, 1);
 
 
	glActiveTexture(GL_TEXTURE2);	
	glBindTexture( GL_TEXTURE_2D, texture3 );
	texLoc = glGetUniformLocation(ShaderProgram, "tex3");
	glUniform1i(texLoc, 2);
 
	glActiveTexture(GL_TEXTURE3);	
	glBindTexture( GL_TEXTURE_2D, texture4 );
	texLoc = glGetUniformLocation(ShaderProgram, "tex4");
	glUniform1i(texLoc, 3);
 
	glActiveTexture(GL_TEXTURE4);	
	glBindTexture( GL_TEXTURE_2D, texture5 );
	texLoc = glGetUniformLocation(ShaderProgram, "tex5");
	glUniform1i(texLoc, 4);

[-NiCo-]

That code looks fine,but I see that you call

texLoc = glGetUniformLocation(ShaderProgram, "tex1");

while there's no "tex1" in your fragment shader...

[Ftored]

This is weird. It was wrong but it worked just fine:$. I fixed that but my problem still remains

[-NiCo-]

Well, from the code you posted I can't see what's wrong. If you can write a small glut-based app illustrating the problem than I'd be happy to take a look at it.