[Mesa-dev] [PATCH] mesa: Add unpack_uint_z_row support for floating-point depth buffers

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

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.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
 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 cd16a9e..b45dde2 100644
--- a/src/mesa/main/format_unpack.c
+++ b/src/mesa/main/format_unpack.c
@@ -2916,6 +2916,32 @@ 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.
@@ -2943,6 +2969,12 @@ _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));
-- 
1.7.6.4