[Mesa-dev] [PATCH] nv50, nvc0: only clear out the buffers that we were asked to clear

[Ilia Mirkin]

On Thu, Jan 23, 2014 at 3:11 PM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 17/01/14 02:23, Ilia Mirkin wrote:
>> Fixes fbo-drawbuffers-none glClearBuffer piglit test.
>>
>> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
>> ---
>>
>> Only tested on nv50, but implementations seem similar enough.
>>
>>  src/gallium/drivers/nouveau/nv50/nv50_surface.c | 17 +++++++++--------
>>  src/gallium/drivers/nouveau/nvc0/nvc0_surface.c | 17 +++++++++--------
>>  2 files changed, 18 insertions(+), 16 deletions(-)
>>
>> diff --git a/src/gallium/drivers/nouveau/nv50/nv50_surface.c b/src/gallium/drivers/nouveau/nv50/nv50_surface.c
>> index 358f57a..eb27429 100644
>> --- a/src/gallium/drivers/nouveau/nv50/nv50_surface.c
>> +++ b/src/gallium/drivers/nouveau/nv50/nv50_surface.c
>> @@ -408,9 +408,6 @@ nv50_clear(struct pipe_context *pipe, unsigned buffers,
>>        PUSH_DATAf(push, color->f[1]);
>>        PUSH_DATAf(push, color->f[2]);
>>        PUSH_DATAf(push, color->f[3]);
>> -      mode =
>> -         NV50_3D_CLEAR_BUFFERS_R | NV50_3D_CLEAR_BUFFERS_G |
>> -         NV50_3D_CLEAR_BUFFERS_B | NV50_3D_CLEAR_BUFFERS_A;
>>     }
>>
> I'm not sure why you've dropped the mode from above. I'm guessing that
> the initial assumption was that if there is a color buffer it must be at
> cbuf[0].

Because I cleared the cbufs separately in a for loop below (the 0x3c
== the RGBA mask). The first RT may not have been there, and that
seemed simpler than the thing that I have now (as evidenced by the
code I have now which has more complex logic).

>
> The corrected version in your github branch looks alot better, it
> handles the above case and does not overwrite the clear buffer on rt0.

Christoph was really keen on doing the common-case color/depth clear
all in one clear buffers command, so yeah -- I redid it that way.
Enjoy the layered version of that in a later commit.

>
> That one is Reviewed-by: Emil Velikov <emil.l.velikov at gmail.com>
>>     if (buffers & PIPE_CLEAR_DEPTH) {
>> @@ -425,12 +422,16 @@ nv50_clear(struct pipe_context *pipe, unsigned buffers,
>>        mode |= NV50_3D_CLEAR_BUFFERS_S;
>>     }
>>
>> -   BEGIN_NV04(push, NV50_3D(CLEAR_BUFFERS), 1);
>> -   PUSH_DATA (push, mode);
>> -
>> -   for (i = 1; i < fb->nr_cbufs; i++) {
>> +   if (mode) {
>>        BEGIN_NV04(push, NV50_3D(CLEAR_BUFFERS), 1);
>> -      PUSH_DATA (push, (i << 6) | 0x3c);
>> +      PUSH_DATA (push, mode);
>> +   }
>> +
>> +   for (i = 0; i < fb->nr_cbufs; i++) {
>> +      if (buffers & (PIPE_CLEAR_COLOR0 << i)) {
>> +         BEGIN_NV04(push, NV50_3D(CLEAR_BUFFERS), 1);
>> +         PUSH_DATA (push, (i << 6) | 0x3c);
>> +      }
>>     }
>>  }
>>
>> diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
>> index 5375bd4..0c12bce 100644
>> --- a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
>> +++ b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
>> @@ -427,9 +427,6 @@ nvc0_clear(struct pipe_context *pipe, unsigned buffers,
>>        PUSH_DATAf(push, color->f[1]);
>>        PUSH_DATAf(push, color->f[2]);
>>        PUSH_DATAf(push, color->f[3]);
>> -      mode =
>> -         NVC0_3D_CLEAR_BUFFERS_R | NVC0_3D_CLEAR_BUFFERS_G |
>> -         NVC0_3D_CLEAR_BUFFERS_B | NVC0_3D_CLEAR_BUFFERS_A;
>>     }
>>
>>     if (buffers & PIPE_CLEAR_DEPTH) {
>> @@ -444,12 +441,16 @@ nvc0_clear(struct pipe_context *pipe, unsigned buffers,
>>        mode |= NVC0_3D_CLEAR_BUFFERS_S;
>>     }
>>
>> -   BEGIN_NVC0(push, NVC0_3D(CLEAR_BUFFERS), 1);
>> -   PUSH_DATA (push, mode);
>> -
>> -   for (i = 1; i < fb->nr_cbufs; i++) {
>> +   if (mode) {
>>        BEGIN_NVC0(push, NVC0_3D(CLEAR_BUFFERS), 1);
>> -      PUSH_DATA (push, (i << 6) | 0x3c);
>> +      PUSH_DATA (push, mode);
>> +   }
>> +
>> +   for (i = 0; i < fb->nr_cbufs; i++) {
>> +      if (buffers & (PIPE_CLEAR_COLOR0 << i)) {
>> +         BEGIN_NVC0(push, NVC0_3D(CLEAR_BUFFERS), 1);
>> +         PUSH_DATA (push, (i << 6) | 0x3c);
>> +      }
>>     }
>>  }
>>
>>
>