[Mesa-dev] [PATCH] svga: allow non-contiguous VS input declarations

[Charmaine Lee]

>From: Brian Paul <brianp at vmware.com>
>Sent: Thursday, February 18, 2016 7:51 AM
>To: mesa-dev at lists.freedesktop.org
>Cc: Charmaine Lee
>Subject: [PATCH] svga: allow non-contiguous VS input declarations
>
>This fixes a glDrawPixels regression since b63fe0552b5f.  The new
>quad-drawing utility code uses 3 vertex attributes (xyz, rgba, st).
>For glDrawPixels path we don't use the rgba attribute so there's a
>gap in the TGSI VS input declarations (INPUT[0] = pos, INPUT[2] =
>texcoord).  The TGSI->VGPU10 translations code did not handle this
>correctly.  I missed this because my VM was configured for HWv11
>while testing.
>
>Another way to fix this would be to change the tgsi_scan.c code so
>that the tgsi_shader_info::num_inputs (and num_outputs) included
>the unused inputs/outputs.  These counts would then actually be
>"max input register index + 1" rather than "number of used inputs".
>But that change could impact all drivers so put it off for now.
>
>No regressions found with piglit or typical GL apps.
>---
> src/gallium/drivers/svga/svga_tgsi_vgpu10.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/src/gallium/drivers/svga/svga_tgsi_vgpu10.c b/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
>index 1223e44..384fb9e 100644
>--- a/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
>+++ b/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
>@@ -2446,7 +2446,7 @@ emit_input_declarations(struct svga_shader_emitter_v10 *emit)
>    else {
>       assert(emit->unit == PIPE_SHADER_VERTEX);
>>
>-      for (i = 0; i < emit->info.num_inputs; i++) {
>+      for (i = 0; i < emit->info.file_max[TGSI_FILE_INPUT] + 1; i++) {
>          unsigned usage_mask = emit->info.input_usage_mask[i];
>          unsigned index = i;

num_inputs are referenced in other functions as well such as svga_get_generic_inputs_mask,
don't we need to fix those as well?

-Charmaine