Mesa (7.11): i915: Disable the depth test whenever we don' t have a depth buffer.

[Eric Anholt]

Module: Mesa
Branch: 7.11
Commit: ea241750f7d92eeeea494049121acdf200c68189
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ea241750f7d92eeeea494049121acdf200c68189

Author: Eric Anholt <eric at anholt.net>
Date:   Tue Jul 12 10:48:40 2011 -0700

i915: Disable the depth test whenever we don't have a depth buffer.

We were disabling it once at the moment we changed draw buffers, but
later enabling of depth test could turn it back on.  Fixes
fbo-nodepth-test.

Note that ctx->DrawBuffer has to be checked because during context
create we get called while it's still unset.  However, we know we'll
get an intel_draw_buffer() after that, so it's safe to make a silly
choice at this point.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=30080
(cherry picked from commit fc4fba52cf7e9616c70dd76b4d6bdba6582e157b)

---

 src/mesa/drivers/dri/i915/i915_state.c |    7 +++++++
 src/mesa/drivers/dri/i915/i915_vtbl.c  |    3 +--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i915/i915_state.c b/src/mesa/drivers/dri/i915/i915_state.c
index 99212ad..73dda65 100644
--- a/src/mesa/drivers/dri/i915/i915_state.c
+++ b/src/mesa/drivers/dri/i915/i915_state.c
@@ -375,6 +375,9 @@ i915DepthMask(struct gl_context * ctx, GLboolean flag)
 
    DBG("%s flag (%d)\n", __FUNCTION__, flag);
 
+   if (!ctx->DrawBuffer || !ctx->DrawBuffer->Visual.depthBits)
+      flag = false;
+
    dw = i915->state.Ctx[I915_CTXREG_LIS6];
    if (flag && ctx->Depth.Test)
       dw |= S6_DEPTH_WRITE_ENABLE;
@@ -797,6 +800,10 @@ i915Enable(struct gl_context * ctx, GLenum cap, GLboolean state)
 
    case GL_DEPTH_TEST:
       dw = i915->state.Ctx[I915_CTXREG_LIS6];
+
+      if (!ctx->DrawBuffer || !ctx->DrawBuffer->Visual.depthBits)
+	 state = false;
+
       if (state)
          dw |= S6_DEPTH_TEST_ENABLE;
       else
diff --git a/src/mesa/drivers/dri/i915/i915_vtbl.c b/src/mesa/drivers/dri/i915/i915_vtbl.c
index ea33304..b3b55b2 100644
--- a/src/mesa/drivers/dri/i915/i915_vtbl.c
+++ b/src/mesa/drivers/dri/i915/i915_vtbl.c
@@ -800,8 +800,7 @@ i915_update_draw_buffer(struct intel_context *intel)
    /*
     * Update depth and stencil test state
     */
-   ctx->Driver.Enable(ctx, GL_DEPTH_TEST,
-		      (ctx->Depth.Test && fb->Visual.depthBits > 0));
+   ctx->Driver.Enable(ctx, GL_DEPTH_TEST, ctx->Depth.Test);
    ctx->Driver.Enable(ctx, GL_STENCIL_TEST,
 		      (ctx->Stencil.Enabled && fb->Visual.stencilBits > 0));