diff options
| author | Kenneth Graunke <[email protected]> | 2012-08-13 00:35:41 -0700 |
|---|---|---|
| committer | Kenneth Graunke <[email protected]> | 2012-08-13 19:16:38 -0700 |
| commit | 605f964d5cc7016fc74e0563829fa794da845c20 (patch) | |
| tree | 5fbf7b3e6dce8401d849d1086ed51c0168f217e5 /src | |
| parent | 43e3a7533d5537e48cef23588131dd25d938ee4b (diff) | |
mesa: Use GLdouble for depthMax in final unpack conversions.
The final step of _mesa_unpack_depth_span is to take the temporary
GLfloat depth values and convert them to the desired format. When
converting to GL_UNSIGNED_INTEGER with depthMax > 0xffffff, we use
double-precision math to avoid overflow and precision problems.
Or at least that's the idea. Unfortunately
GLdouble z = depthValues[i] * (GLfloat) depthMax;
actually causes single-precision multiplication, since both operands are
GLfloats. Casting depthMax to GLdouble causes the scaling to be done
with double-precision math.
Fixes a regression in oglconform's depth-stencil basic.read.ds test
since c60ac7b17993d28af65b04f9bbbf3ee74c35358c, where the expected and
actual values differed slightly. For example, 0xcfa7a6 vs. 0xcfa7a4.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49772
Signed-off-by: Kenneth Graunke <[email protected]>
Diffstat (limited to 'src')
| -rw-r--r-- | src/mesa/main/pack.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/mesa/main/pack.c b/src/mesa/main/pack.c index 83192c1574c..672a467aa1c 100644 --- a/src/mesa/main/pack.c +++ b/src/mesa/main/pack.c @@ -4913,7 +4913,7 @@ _mesa_unpack_depth_span( struct gl_context *ctx, GLuint n, else { /* need to use double precision to prevent overflow problems */ for (i = 0; i < n; i++) { - GLdouble z = depthValues[i] * (GLfloat) depthMax; + GLdouble z = depthValues[i] * (GLdouble) depthMax; if (z >= (GLdouble) 0xffffffff) zValues[i] = 0xffffffff; else |