On 07/24/2017 11:05 AM, Charmaine Lee wrote:
From: Brian Paul <bri...@vmware.com>
Sent: Saturday, July 22, 2017 12:24 PM
To: mesa-dev@lists.freedesktop.org
Cc: Charmaine Lee; Neha Bhende
Subject: [PATCH 2/2] svga: implement MSAA alpha_to_one feature
The device doesn't directly support this feature so we implement it with
additional shader code which sets the color output(s) w component to
1.0 (or max_int or max_uint).
Fixes 16 Piglit ext_framebuffer_multisample/*alpha-to-one* tests.
---
src/gallium/drivers/svga/svga_context.h | 1 +
src/gallium/drivers/svga/svga_pipe_blend.c | 1 +
src/gallium/drivers/svga/svga_shader.h | 3 ++
src/gallium/drivers/svga/svga_state_fs.c | 18 +++++++++
src/gallium/drivers/svga/svga_tgsi_vgpu10.c | 61 ++++++++++++++++++++++++++++-
5 files changed, 83 insertions(+), 1 deletion(-)
...
diff --git a/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
b/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
index 9f5cd4b..8984ce5 100644
--- a/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
+++ b/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
...
@@ -6378,6 +6393,47 @@ emit_pre_helpers(struct svga_shader_emitter_v10
*emit)
/**
+ * The device has no direct support for the pipe_blend_state::alpha_to_one
+ * option so we implement it here with shader code.
+ */
+static void
+emit_alpha_to_one_instructions(struct svga_shader_emitter_v10 *emit,
+ unsigned fs_color_tmp_index)
+{
+ unsigned i;
+
+ for (i = 0; i < emit->fs.num_color_outputs; i++) {
+ struct tgsi_full_dst_register color_dst;
+
+ if (fs_color_tmp_index != INVALID_INDEX && i == 0) {
+ /* write to the temp color register */
+ color_dst = make_dst_temp_reg(fs_color_tmp_index);
+ }
+ else {
+ /* write directly to the color[i] output */
+ color_dst = make_dst_output_reg(emit->fs.color_out_index[i]);
+ }
+
+ color_dst = writemask_dst(&color_dst, TGSI_WRITEMASK_W);
+
+ /* Depending on type of the render target, we either set alpha/w to
+ * 1.0f, or max(int) or max(uint).
+ */
+ struct tgsi_full_src_register one;
+ if (emit->key.fs.int_render_target_mask & (1 << i)) {
+ one = make_immediate_reg_int(emit, 0x8fffffff);
+ } else if (emit->key.fs.uint_render_target_mask & (1 << i)) {
+ one = make_immediate_reg_int(emit, 0xffffffff);
+ } else {
+ one = make_immediate_reg_float(emit, 1.0f);
+ }
How about moving the various "make one immediate" outside of the loop?
No need to repeatedly looking for the same immediate.
Roland reminded me that alpha-to-one is not applicable to int buffers so
I can just remove that.
-Brian
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