[Mesa-dev] [PATCH] anv: fix viewport transformation for z component

[Samuel Iglesias Gonsálvez]

In Vulkan, for 'z' (depth) component, the scale and translate values
for the viewport transformation are:

pz = maxDepth - minDepth
oz = minDepth

zf = pz × zd + oz

Being zd, the third component in vertex's normalized device coordinates.

Fixes: dEQP-VK.draw.inverted_depth_ranges.*

Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
---
 src/intel/vulkan/gen8_cmd_buffer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/intel/vulkan/gen8_cmd_buffer.c b/src/intel/vulkan/gen8_cmd_buffer.c
index 064b8e930e..7bea231ea7 100644
--- a/src/intel/vulkan/gen8_cmd_buffer.c
+++ b/src/intel/vulkan/gen8_cmd_buffer.c
@@ -49,10 +49,10 @@ gen8_cmd_buffer_emit_viewport(struct anv_cmd_buffer *cmd_buffer)
       struct GENX(SF_CLIP_VIEWPORT) sf_clip_viewport = {
          .ViewportMatrixElementm00 = vp->width / 2,
          .ViewportMatrixElementm11 = vp->height / 2,
-         .ViewportMatrixElementm22 = 1.0,
+         .ViewportMatrixElementm22 = vp->maxDepth - vp->minDepth,
          .ViewportMatrixElementm30 = vp->x + vp->width / 2,
          .ViewportMatrixElementm31 = vp->y + vp->height / 2,
-         .ViewportMatrixElementm32 = 0.0,
+         .ViewportMatrixElementm32 = vp->minDepth,
          .XMinClipGuardband = -1.0f,
          .XMaxClipGuardband = 1.0f,
          .YMinClipGuardband = -1.0f,
-- 
2.14.1