draw/translate: fix instancing

We were incorrectly computing the buffer offset when using the
instances. The buffer offset is always equal to:
start_instance * stride + (instance_num / instance_divisor) *
stride
We were completely ignoring the start instance quite
often producing instances that completely wrong, e.g. if
start instance = 5, instance divisor = 2, then on the first
iteration it should be:
5 * stride, not (5/2) * stride as we'd have currently, and if
start instance = 1, instance divisor = 3, then on the first
iteration it should be:
1 * stride, not 0 as we'd have.
This fixes it and adjusts all the code to the changes.

Signed-off-by: Zack Rusin <[email protected]>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/draw/draw_vs_variant.c b/src/gallium/auxiliary/draw/draw_vs_variant.c
index 152c1303183..37500c7db8d 100644
--- a/src/gallium/auxiliary/draw/draw_vs_variant.c
+++ b/src/gallium/auxiliary/draw/draw_vs_variant.c
@@ -168,6 +168,7 @@ static void PIPE_CDECL vsvg_run_elts( struct draw_vs_variant *variant,
    vsvg->fetch->run_elts( vsvg->fetch, 
                           elts,
                           count,
+                          vsvg->draw->start_instance,
                           vsvg->draw->instance_id,
                           temp_buffer );
 
@@ -211,6 +212,7 @@ static void PIPE_CDECL vsvg_run_elts( struct draw_vs_variant *variant,
 
    vsvg->emit->run( vsvg->emit,
                     0, count,
+                    vsvg->draw->start_instance,
                     vsvg->draw->instance_id,
                     output_buffer );
 
@@ -234,6 +236,7 @@ static void PIPE_CDECL vsvg_run_linear( struct draw_vs_variant *variant,
    vsvg->fetch->run( vsvg->fetch, 
                      start,
                      count,
+                     vsvg->draw->start_instance,
                      vsvg->draw->instance_id,
                      temp_buffer );
 
@@ -274,6 +277,7 @@ static void PIPE_CDECL vsvg_run_linear( struct draw_vs_variant *variant,
    
    vsvg->emit->run( vsvg->emit,
                     0, count,
+                    vsvg->draw->start_instance,
                     vsvg->draw->instance_id,
                     output_buffer );