gallium/util: implement layered framebuffer clear in u_blitter

All bound layers (from first_layer to last_layer) should be cleared.

This uses a vertex shader which outputs gl_Layer = gl_InstanceID, so each
instance goes to a different layer. By rendering a quad and setting
the instance count to the number of layers, it will trivially clear all
layers.

This requires AMD_vertex_shader_layer (or PIPE_CAP_TGSI_VS_LAYER), which only
radeonsi supports at the moment. r600 could do this too. Standard DX11
hardware will have to use a geometry shader though, which has higher overhead.

4 files changed, 4 insertions, 5 deletions

diff --git a/src/gallium/drivers/ilo/ilo_blitter_pipe.c b/src/gallium/drivers/ilo/ilo_blitter_pipe.c
index b4dd3ad91c5..fa4f1582b7f 100644
--- a/src/gallium/drivers/ilo/ilo_blitter_pipe.c
+++ b/src/gallium/drivers/ilo/ilo_blitter_pipe.c
@@ -220,7 +220,7 @@ ilo_blitter_pipe_clear_fb(struct ilo_blitter *blitter,
    ilo_blitter_pipe_begin(blitter, ILO_BLITTER_PIPE_CLEAR_FB, false);
 
    util_blitter_clear(blitter->pipe_blitter,
-         blitter->ilo->fb.state.width, blitter->ilo->fb.state.height,
+         blitter->ilo->fb.state.width, blitter->ilo->fb.state.height, 1,
          buffers, color, depth, stencil);
 
    ilo_blitter_pipe_end(blitter);
diff --git a/src/gallium/drivers/r300/r300_blit.c b/src/gallium/drivers/r300/r300_blit.c
index 4ec68ae6e1c..42410fe7dae 100644
--- a/src/gallium/drivers/r300/r300_blit.c
+++ b/src/gallium/drivers/r300/r300_blit.c
@@ -365,9 +365,7 @@ static void r300_clear(struct pipe_context* pipe,
     if (buffers) {
         /* Clear using the blitter. */
         r300_blitter_begin(r300, R300_CLEAR);
-        util_blitter_clear(r300->blitter,
-                           width,
-                           height,
+        util_blitter_clear(r300->blitter, width, height, 1,
                            buffers, color, depth, stencil);
         r300_blitter_end(r300);
     } else if (r300->zmask_clear.dirty ||
diff --git a/src/gallium/drivers/r600/r600_blit.c b/src/gallium/drivers/r600/r600_blit.c
index fea33bccaa8..f33bb43b8c6 100644
--- a/src/gallium/drivers/r600/r600_blit.c
+++ b/src/gallium/drivers/r600/r600_blit.c
@@ -558,7 +558,7 @@ static void r600_clear(struct pipe_context *ctx, unsigned buffers,
 	}
 
 	r600_blitter_begin(ctx, R600_CLEAR);
-	util_blitter_clear(rctx->blitter, fb->width, fb->height,
+	util_blitter_clear(rctx->blitter, fb->width, fb->height, 1,
 			   buffers, color, depth, stencil);
 	r600_blitter_end(ctx);
 
diff --git a/src/gallium/drivers/radeonsi/r600_blit.c b/src/gallium/drivers/radeonsi/r600_blit.c
index 851b80c5484..e525f7950b0 100644
--- a/src/gallium/drivers/radeonsi/r600_blit.c
+++ b/src/gallium/drivers/radeonsi/r600_blit.c
@@ -332,6 +332,7 @@ static void r600_clear(struct pipe_context *ctx, unsigned buffers,
 
 	r600_blitter_begin(ctx, R600_CLEAR);
 	util_blitter_clear(rctx->blitter, fb->width, fb->height,
+			   util_framebuffer_get_num_layers(fb),
 			   buffers, color, depth, stencil);
 	r600_blitter_end(ctx);
 }