Mesa (8.0): mesa: Add unpack_uint_z_row support for floating-point depth buffers

[Ian Romanick]

Module: Mesa
Branch: 8.0
Commit: 9da7b58b39658f9d42777a4cb387bb668b28d491
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9da7b58b39658f9d42777a4cb387bb668b28d491

Author: Ian Romanick <ian.d.romanick at intel.com>
Date:   Wed Jan 18 11:56:12 2012 -0800

mesa: Add unpack_uint_z_row support for floating-point depth buffers

This is a hack, and it will result in incorrect rendering.  However,
it does eliminate spurious warnings in several piglit CopyPixels tests
that involve floating-point depth buffers.

The real solution is to add a zf field to SWspan to store float Z
values.  When a float depth buffer is involved, swrast should also
populate the zf field.  I'll consider this post-8.0 work.

NOTE: This is a candidate for the 8.0 branch.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
(cherry picked from commit af1477b088448aeca762f515410c80054cb225b9)

---

 src/mesa/main/format_unpack.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/src/mesa/main/format_unpack.c b/src/mesa/main/format_unpack.c
index ff98c69..be39873 100644
--- a/src/mesa/main/format_unpack.c
+++ b/src/mesa/main/format_unpack.c
@@ -2537,6 +2537,32 @@ unpack_uint_z_Z32(const void *src, GLuint *dst, GLuint n)
    memcpy(dst, src, n * sizeof(GLuint));
 }
 
+static void
+unpack_uint_z_Z32_FLOAT(const void *src, GLuint *dst, GLuint n)
+{
+   const float *s = (const float *)src;
+   GLuint i;
+   for (i = 0; i < n; i++) {
+      dst[i] = FLOAT_TO_UINT(IROUND(CLAMP((s[i]), 0.0F, 1.0F)));
+   }
+}
+
+static void
+unpack_uint_z_Z32_FLOAT_X24S8(const void *src, GLuint *dst, GLuint n)
+{
+   struct z32f_x24s8 {
+      float z;
+      uint32_t x24s8;
+   };
+
+   const struct z32f_x24s8 *s = (const struct z32f_x24s8 *) src;
+   GLuint i;
+
+   for (i = 0; i < n; i++) {
+      dst[i] = FLOAT_TO_UINT(IROUND(CLAMP((s[i].z), 0.0F, 1.0F)));
+   }
+}
+
 
 /**
  * Unpack Z values.
@@ -2564,6 +2590,12 @@ _mesa_unpack_uint_z_row(gl_format format, GLuint n,
    case MESA_FORMAT_Z32:
       unpack = unpack_uint_z_Z32;
       break;
+   case MESA_FORMAT_Z32_FLOAT:
+      unpack = unpack_uint_z_Z32_FLOAT;
+      break;
+   case MESA_FORMAT_Z32_FLOAT_X24S8:
+      unpack = unpack_uint_z_Z32_FLOAT_X24S8;
+      break;
    default:
       _mesa_problem(NULL, "bad format %s in _mesa_unpack_uint_z_row",
                     _mesa_get_format_name(format));