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

[Marek Olšák]

Module: Mesa
Branch: master
Commit: f76787b3eae3f0b8af839fabfb24b57715a017f6
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f76787b3eae3f0b8af839fabfb24b57715a017f6

Author: Marek Olšák <maraeo at gmail.com>
Date:   Sun May 29 04:36:36 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

---

 src/gallium/drivers/r300/r300_emit.c  |   13 +++++++++++++
 src/gallium/drivers/r300/r300_state.c |   20 ++++++++++++++------
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/gallium/drivers/r300/r300_emit.c b/src/gallium/drivers/r300/r300_emit.c
index 874037e..5d6188e 100644
--- a/src/gallium/drivers/r300/r300_emit.c
+++ b/src/gallium/drivers/r300/r300_emit.c
@@ -439,6 +439,19 @@ void r300_emit_fb_state(struct r300_context* r300, unsigned size, void* state)
             OUT_CS_REG(R300_ZB_ZMASK_OFFSET, 0);
             OUT_CS_REG(R300_ZB_ZMASK_PITCH, surf->pitch_zmask);
         }
+    /* 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]);
+
+        OUT_CS_REG(R300_ZB_FORMAT, R300_DEPTHFORMAT_16BIT_INT_Z);
+
+        OUT_CS_REG(R300_ZB_DEPTHOFFSET, 0);
+        OUT_CS_RELOC(surf);
+
+        OUT_CS_REG(R300_ZB_DEPTHPITCH, 4 | R300_DEPTHMICROTILE_TILED);
+        OUT_CS_RELOC(surf);
     }
 
     END_CS;
diff --git a/src/gallium/drivers/r300/r300_state.c b/src/gallium/drivers/r300/r300_state.c
index bc6c67d..84d9da3 100644
--- a/src/gallium/drivers/r300/r300_state.c
+++ b/src/gallium/drivers/r300/r300_state.c
@@ -549,6 +549,10 @@ 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. */
@@ -632,11 +636,13 @@ static void*
     OUT_CB_REG(R500_FG_ALPHA_VALUE, dsa->alpha_value);
     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_zb_no_readwrite, 10);
     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);
     OUT_CB_REG(R500_FG_ALPHA_VALUE, dsa->alpha_value);
@@ -645,8 +651,8 @@ static void*
     BEGIN_CB(dsa->cb_fp16_zb_no_readwrite, 10);
     OUT_CB_REG(R300_FG_ALPHA_FUNC, dsa->alpha_function_fp16);
     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);
     OUT_CB_REG(R500_FG_ALPHA_VALUE, dsa->alpha_value);
@@ -792,12 +798,14 @@ 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 (r300->hyperz_enabled)
             r300->fb_state.size += 8;
+    } else if (state->nr_cbufs) {
+        r300->fb_state.size += 10;
     }
 
     /* The size of the rest of atoms stays the same. */