opengl - Why can't I render my depth map on a quad?

Question

Some intro:

I'm currently trying to see how I can convert a depth map into a point cloud. In order to do this, I render a scene as usually and produce a depth map. From the depth map I try to recreate the scene as a point cloud from the given camera angle.

In order to do this I created a FBO so I can render my scene's depth map on a texture. The depth map is rendered on the texture successfully. I know it is done because I'm able to generate the point cloud from the depth texture using glGetTexImage and converting the data acquired.

The problem:

For presentation purposes, I want the depth map to be visible on a separate window. So, I just created a simple shader to draw the depth map texture on a quad. However, instead of the depth texture being drawn on the quad, the texture being drawn is the last that was bound using GlBindTexture. For example :

 glUseProgram(simpleTextureViewerProgram);
 glBindVertexArray(quadVAO);
 glActiveTexture(GL_TEXTURE0);
 glBindTexture(GL_TEXTURE_2D,randomTexture);
 glBindTexture(GL_TEXTURE_2D, depthTexture);
 glUniform1i(quadTextureSampler, 0);
 glDrawArrays(GL_TRIANGLES, 0, 6);

The code above renders the "randomTexure" on the quad instead of the "depthTexture". As I said earlier, "depthTexture" is the one I use in glGetTexImage, so it does contain the depth map.

I may be wrong but if I had to make a guess then the last GlBindTexture command fails and the problem is that "depthTexture" is not an RGB texture but a depth component texture. Is this the reason? How can I draw my depth map on the quad then?

question from:https://stackoverflow.com/questions/65870882/why-cant-i-render-my-depth-map-on-a-quad

Answer 1

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