<div dir="ltr">On 19 July 2013 17:32, Jordan Justen <span dir="ltr"><<a href="mailto:jordan.l.justen@intel.com" target="_blank">jordan.l.justen@intel.com</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">For gen >= 7, we will use the lod/minimum-array-element fields to<br>
support layered rendering. This means that we must restrict<br>
the depth & stencil attachments to match in various more retrictive<br>
ways. (Now the width, height, depth, LOD and layer must match)<br>
<br>
Signed-off-by: Jordan Justen <<a href="mailto:jordan.l.justen@intel.com">jordan.l.justen@intel.com</a>><br>
Cc: Paul Berry <<a href="mailto:stereotype441@gmail.com">stereotype441@gmail.com</a>><br></blockquote><div><br></div><div>Since this is the commit we're going to bisect back to if a client program ever runs into trouble for violating these restrictions, it would be nice to have a little bit more exposition here in the commit message. In particular it's not obvious why the width, height, and depth must match. It also would be nice to say something about what our fallback plan is if this the new restrictions prove too onerous. How about adding some text like this to the commit message?<br>
<br></div><div>The reason width, height, and depth must match is that the hardware has a single set of width, height, and depth settings (in 3DSTATE_DEPTH_BUFFER) that affect both the depth and stencil buffers. Since these controls determine the miptree layout, they need to be set correctly in order for lod and minimum-array-element to work properly. So the only way rendering can work is if the width, height, and depth match.<br>
<br></div><div>In the future, if this restriction proves to be a problem (say because some crucial client application relies on rendering to different levels/layers of stencil and depth buffers), then we can always work around the restriction by copying depth and/or stencil data to a temporary buffer prior to rendering (much in the same way that brw_workaround_depthstencil_alignment() does today for gen < 7), but hopefully that won't be necessary.<br>
<br><br></div><div>With the addition of the above text (or something like it), this patch is:<br><br></div><div>Reviewed-by: Paul Berry <<a href="mailto:stereotype441@gmail.com">stereotype441@gmail.com</a>><br></div>
<div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
---<br>
src/mesa/drivers/dri/i965/intel_fbo.c | 16 ++++++++++++++++<br>
1 file changed, 16 insertions(+)<br>
<br>
diff --git a/src/mesa/drivers/dri/i965/intel_fbo.c b/src/mesa/drivers/dri/i965/intel_fbo.c<br>
index e746cb4..1826a29 100644<br>
--- a/src/mesa/drivers/dri/i965/intel_fbo.c<br>
+++ b/src/mesa/drivers/dri/i965/intel_fbo.c<br>
@@ -569,6 +569,22 @@ intel_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)<br>
}<br>
<br>
if (depth_mt && stencil_mt) {<br>
+ if (brw->gen >= 7) {<br>
+ /* For gen >= 7, we are using the lod/minimum-array-element fields<br>
+ * and supportting layered rendering. This means that we must restrict<br>
+ * the depth & stencil attachments to match in various more retrictive<br>
+ * ways. (width, height, depth, LOD and layer)<br>
+ */ <br></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
+ if (depth_mt->physical_width0 != stencil_mt->physical_width0 ||<br>
+ depth_mt->physical_height0 != stencil_mt->physical_height0 ||<br>
+ depth_mt->physical_depth0 != stencil_mt->physical_depth0 ||<br>
+ depthRb->mt_level != stencilRb->mt_level ||<br>
+ depthRb->mt_layer != stencilRb->mt_layer) {<br>
+ fbo_incomplete(fb,<br>
+ "FBO incomplete: depth and stencil must match in"<br>
+ "width, height, depth, LOD and layer\n");<br>
+ }<br>
+ }<br>
if (depth_mt == stencil_mt) {<br>
/* For true packed depth/stencil (not faked on prefers-separate-stencil<br>
* hardware) we need to be sure they're the same level/layer, since<br>
<span class=""><font color="#888888">--<br>
1.7.10.4<br>
<br>
</font></span></blockquote></div><br></div></div>