[SOLVED] Depth Texture Lookup Problem

Hey guys, I'm having a bit of an issue getting the correct texture coordinate while rendering.

Basically, I've got a 2 pass engine right now, the first pass renders to a framebuffer object that captures all the color, normal, and depth information into 3 textures. Then in the second pass I draw the scene normally, but with my shaders attached. In the fragment shader I want to lookup depth values from my texture, and use that for SSAO, but firstly just to visualize the depth map.

My problem is that when rendering to the screen regularly and using my fragment shader, how can I find out what coordinates to look up in the depth texture?

Any help would be greatly appreciated!

Code below:

C++

   /////////////////////////////////////////////////////////////////////////////   //// PASS 1 (write to textures)   /////////////////////////////////////////////////////////////////////////////   //Setup   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, frameBuffer);   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);   glEnable(GL_DEPTH_TEST);      ////// RENDERING ///////   updateView(); // set the viewing transform   updateLight(); // set the light sources   updateGeom(); // Draw objects   /////////////////////////////////////////////////////////////////////////////   //// PASS 2 (write to screen)   /////////////////////////////////////////////////////////////////////////////   //Setup   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);   glEnable(GL_DEPTH_TEST);   //attach shader and set it up   shader->attach();   GLint loc = glGetUniformLocation(shader->shaderProg, "depthTex");   glUniform1i(loc,0);   glActiveTexture(GL_TEXTURE0);   glBindTexture(GL_TEXTURE_2D, textures[color]);   ////// RENDERING ///////   updateView(); // set the viewing transform   updateLight(); // set the light sources   updateGeom(); // Draw objects   // Tear down   shader->detach();   glutSwapBuffers(); // Swap the double buffer.   glutPostRedisplay();

vertex shader:

    varying vec3 normal;    varying vec4 pos;    void main()    {        //Grab the texture coord for depth map lookup        gl_TexCoord[0].xy = gl_MultiTexCoord0.xy;           //Same old, same old        normal = gl_NormalMatrix * gl_Normal;        pos = gl_ModelViewMatrix * gl_Vertex;	gl_Position = ftransform();     } 

fragment shader:

    varying vec3 normal;    varying vec4 pos;    uniform sampler2D depthTex;    float DepthToLinearZ(float dVal)    {        float near = 1.0;        float far = 100.0;        return (-2.0*far*near) / ((dVal*(far-near))-(far+near)); //Inverse of perspective z transform    }    void main()    {        // DEPTH STUFF        vec2 coord = gl_TexCoord[0].xy;        float depth = DepthToLinearZ( texture2D(depthTex, coord).r );        depth = depth / 100.0; //depth over far plane so I get [0,1]        gl_FragColor = vec4(depth, depth, depth, 1.0);    }

[Edited by - Aptos on June 9, 2010 7:59:56 PM]