Mesa (7.10): r300g: fix occlusion queries when depth test is disabled or zbuffer is missing

[Marek Olšák]

Module: Mesa
Branch: 7.10
Commit: bbebbdd3e726b6faaa58b5e1d0044e2b9010969f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=bbebbdd3e726b6faaa58b5e1d0044e2b9010969f

Author: Marek Olšák <maraeo at gmail.com>
Date:   Fri Jun 10 19:00:50 2011 +0200

r300g: fix occlusion queries when depth test is disabled or zbuffer is missing

>From now on, depth test is always enabled in hardware.

If depth test is disabled in Gallium, the hardware Z function is set to ALWAYS.

If there is no zbuffer set, the colorbuffer0 memory is set as a zbuffer
to silence the CS checker.

This fixes piglit:
- occlusion-query-discard
- NV_conditional_render/bitmap
- NV_conditional_render/drawpixels
- NV_conditional_render/vertex_array
(cherry picked from commit f76787b3eae3f0b8af839fabfb24b57715a017f6)

Conflicts:

	src/gallium/drivers/r300/r300_state.c

Squashed with cherry-picked b1246cf13bc4e301b499a95d33e0cab26655fed5.

---

 src/gallium/drivers/r300/r300_emit.c  |   17 +++++++++++++++++
 src/gallium/drivers/r300/r300_state.c |   16 ++++++++++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/r300/r300_emit.c b/src/gallium/drivers/r300/r300_emit.c
index 972f58f..01e63dd 100644
--- a/src/gallium/drivers/r300/r300_emit.c
+++ b/src/gallium/drivers/r300/r300_emit.c
@@ -448,6 +448,23 @@ void r300_emit_fb_state(struct r300_context* r300, unsigned size, void* state)
                 OUT_CS_REG(R300_ZB_ZMASK_PITCH, 0);
             }
         }
+    /* Set up a dummy zbuffer. Otherwise occlusion queries won't work.
+     * Use the first colorbuffer, we will disable writes in the DSA state
+     * so as not to corrupt it. */
+    } else if (fb->nr_cbufs) {
+        surf = r300_surface(fb->cbufs[0]);
+        unsigned tiling =
+            r300->rws->get_value(r300->rws, R300_VID_SQUARE_TILING_SUPPORT) ?
+            R300_DEPTHMICROTILE_TILED_SQUARE :
+            R300_DEPTHMICROTILE_TILED;
+
+        OUT_CS_REG(R300_ZB_FORMAT, R300_DEPTHFORMAT_16BIT_INT_Z);
+
+        OUT_CS_REG_SEQ(R300_ZB_DEPTHOFFSET, 1);
+        OUT_CS_RELOC(surf->cs_buffer, 0, 0, surf->domain);
+
+        OUT_CS_REG_SEQ(R300_ZB_DEPTHPITCH, 1);
+        OUT_CS_RELOC(surf->cs_buffer, 4 | tiling, 0, surf->domain);
     }
 
     END_CS;
diff --git a/src/gallium/drivers/r300/r300_state.c b/src/gallium/drivers/r300/r300_state.c
index f902db5..d3fc940 100644
--- a/src/gallium/drivers/r300/r300_state.c
+++ b/src/gallium/drivers/r300/r300_state.c
@@ -485,6 +485,10 @@ static void*
         dsa->z_stencil_control |=
             (r300_translate_depth_stencil_function(state->depth.func) <<
                 R300_Z_FUNC_SHIFT);
+    } else {
+        /* We must enable depth test, otherwise occlusion queries won't work. */
+        dsa->z_buffer_control |= R300_Z_ENABLE;
+        dsa->z_stencil_control |= R300_ZS_ALWAYS;
     }
 
     /* Stencil buffer setup. */
@@ -554,11 +558,13 @@ static void*
     OUT_CB_REG(R500_ZB_STENCILREFMASK_BF, dsa->stencil_ref_bf);
     END_CB;
 
+    /* We must enable depth test, otherwise occlusion queries won't work.
+     * We setup a dummy zbuffer to silent the CS checker, see emit_fb_state. */
     BEGIN_CB(dsa->cb_no_readwrite, 8);
     OUT_CB_REG(R300_FG_ALPHA_FUNC, dsa->alpha_function);
     OUT_CB_REG_SEQ(R300_ZB_CNTL, 3);
-    OUT_CB(0);
-    OUT_CB(0);
+    OUT_CB(R300_Z_ENABLE);
+    OUT_CB(R300_ZS_ALWAYS);
     OUT_CB(0);
     OUT_CB_REG(R500_ZB_STENCILREFMASK_BF, 0);
     END_CB;
@@ -699,12 +705,14 @@ void r300_mark_fb_state_dirty(struct r300_context *r300,
     /* Now compute the fb_state atom size. */
     r300->fb_state.size = 2 + (8 * state->nr_cbufs);
 
-    if (r300->cbzb_clear)
+    if (r300->cbzb_clear) {
         r300->fb_state.size += 10;
-    else if (state->zsbuf) {
+    } else if (state->zsbuf) {
         r300->fb_state.size += 10;
         if (can_hyperz)
             r300->fb_state.size += r300->screen->caps.hiz_ram ? 8 : 4;
+    } else if (state->nr_cbufs) {
+        r300->fb_state.size += 10;
     }
 
     /* The size of the rest of atoms stays the same. */