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Original post by Inigo Quilez

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Original post by Zelcious Right now I render the scene to a RGBA32F buffer and store the depth in the alpha channel, unfortunatly that means I read 16 bytes each time I sample the depth buffer in the last fullscreen pass. I would like to use RGBA8 and LUMINANCE32F buffer at same time to render scene color and depth. But opengl fbo doesn't allow that.

/// Packing a [0-1] float value into a 4D vector where each component will be a 8-bits integer
vec4 packFloatToVec4i(const float value)
{
	const vec4 bitSh = vec4(256.0 * 256.0 * 256.0, 256.0 * 256.0, 256.0, 1.0);
	const vec4 bitMsk = vec4(0.0, 1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0);
	vec4 res = fract(value * bitSh);
	res -= res.xxyz * bitMsk;
	return res;
}

/// Unpacking a [0-1] float value from a 4D vector where each component was a 8-bits integer
float unpackFloatFromVec4i(const vec4 value)
{
	const vec4 bitSh = vec4(1.0 / (256.0 * 256.0 * 256.0), 1.0 / (256.0 * 256.0), 1.0 / 256.0, 1.0);
	return(dot(value, bitSh));
}

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Original post by Zelcious I would like to use RGBA8 and LUMINANCE32F buffer at same time to render scene color and depth.

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I sent Inigo an email about this, but maybe somebody else has an idea. I'm unsure exactly how this algorithm works when we're basing everything on z difference and not taking into account the surface normals. Example: if I am looking at a flat surface (and no nearby occluders) straight on, the z difference at each sample on the inside of the surface will be 0, or close to 0. When I'm at an angle to the surface the z difference at each sample will change (we could get anything from -2 to 2, say). So we have two problems: flat surfaces self-occlude, which is not what we want, and surfaces will change color as we change our viewing angle because of the change in z difference at each sample (the more straight on we are to a surface, the darker it will get due to smaller z differences). Inigo's screenshots look like he doesn't have the problem of the color changing as the viewing angle changes, at least (though I do see some noise on the flat faces). What am I missing here? Sam McGrath

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To the post above, try using a higher precision depth buffer. My banding artifacts went away when I stored depth as 32F instead of 16F.