Mesa (main): lima: Fix drawing wide lines

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Module: Mesa
Branch: main
Commit: ee41e1bbd2a57f58b616d560451759a4fcd940db
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ee41e1bbd2a57f58b616d560451759a4fcd940db

Author: Andreas Baierl <ichgeh at imkreisrum.de>
Date:   Tue Sep 21 18:21:06 2021 +0200

lima: Fix drawing wide lines

GLES2.0 spec allows parts of wide lines and points to be drawn even if
their center is outside the viewport.
Therefore 0x2000 in PLBU_CMD_PRIMITIVE_SETUP has to be set for points.
This is already our default setting as it seems to have no negative
effect when this bit is always set. Points work as expected but lines
don't. It's hard to RE it, because the affected deqp tests also fail
with the blob.

To respect this behaviour for lines and solve another 2 tests, we need
to do a workaround and temporarily extend the viewport by half of the
line width. The scissor rectangle is still equal with the initial
viewport.

Reviewed-by: Vasily Khoruzhick <anarsoul at gmail.com>
Signed-off-by: Andreas Baierl <ichgeh at imkreisrum.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12971>

---

 src/gallium/drivers/lima/ci/lima-fails.txt |  2 --
 src/gallium/drivers/lima/lima_context.h    |  2 ++
 src/gallium/drivers/lima/lima_draw.c       | 38 ++++++++++++++++++++++++++----
 src/gallium/drivers/lima/lima_state.c      | 12 ++++++----
 4 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/src/gallium/drivers/lima/ci/lima-fails.txt b/src/gallium/drivers/lima/ci/lima-fails.txt
index 4232bffe760..ec9b634fc1e 100644
--- a/src/gallium/drivers/lima/ci/lima-fails.txt
+++ b/src/gallium/drivers/lima/ci/lima-fails.txt
@@ -1,5 +1,3 @@
-dEQP-GLES2.functional.clipping.line.wide_line_clip_viewport_center,Fail
-dEQP-GLES2.functional.clipping.line.wide_line_clip_viewport_corner,Fail
 dEQP-GLES2.functional.clipping.triangle_vertex.clip_two.clip_neg_x_neg_y_pos_z_and_pos_x_pos_y_neg_z,Fail
 dEQP-GLES2.functional.clipping.triangle_vertex.clip_two.clip_neg_x_pos_y_pos_z_and_pos_x_neg_y_neg_z,Fail
 dEQP-GLES2.functional.clipping.triangle_vertex.clip_two.clip_pos_x_neg_y_pos_z_and_neg_x_pos_y_neg_z,Fail
diff --git a/src/gallium/drivers/lima/lima_context.h b/src/gallium/drivers/lima/lima_context.h
index 86a668cb4dc..e871d0b952d 100644
--- a/src/gallium/drivers/lima/lima_context.h
+++ b/src/gallium/drivers/lima/lima_context.h
@@ -209,6 +209,8 @@ struct lima_context {
 
    struct lima_context_framebuffer framebuffer;
    struct lima_context_viewport_state viewport;
+   /* input for PLBU_CMD_VIEWPORT_* */
+   struct lima_context_viewport_state ext_viewport;
    struct pipe_scissor_state scissor;
    struct pipe_scissor_state clipped_scissor;
    struct lima_vs_compiled_shader *vs;
diff --git a/src/gallium/drivers/lima/lima_draw.c b/src/gallium/drivers/lima/lima_draw.c
index c60956629bd..5c9f03b1d1c 100644
--- a/src/gallium/drivers/lima/lima_draw.c
+++ b/src/gallium/drivers/lima/lima_draw.c
@@ -85,6 +85,32 @@ lima_clip_scissor_to_viewport(struct lima_context *ctx)
       cscissor->miny = cscissor->maxy;
 }
 
+static void
+lima_extend_viewport(struct lima_context *ctx, const struct pipe_draw_info *info)
+{
+   /* restore the original values */
+   ctx->ext_viewport.left = ctx->viewport.left;
+   ctx->ext_viewport.right = ctx->viewport.right;
+   ctx->ext_viewport.bottom = ctx->viewport.bottom;
+   ctx->ext_viewport.top = ctx->viewport.top;
+
+   if (info->mode != PIPE_PRIM_LINES)
+      return;
+
+   if (!ctx->rasterizer)
+      return;
+
+   float line_width = ctx->rasterizer->base.line_width;
+
+   if (line_width == 1.0f)
+      return;
+
+   ctx->ext_viewport.left = ctx->viewport.left - line_width / 2;
+   ctx->ext_viewport.right = ctx->viewport.right + line_width / 2;
+   ctx->ext_viewport.bottom = ctx->viewport.bottom - line_width / 2;
+   ctx->ext_viewport.top = ctx->viewport.top + line_width / 2;
+}
+
 static bool
 lima_is_scissor_zero(struct lima_context *ctx)
 {
@@ -327,10 +353,10 @@ lima_pack_plbu_cmd(struct lima_context *ctx, const struct pipe_draw_info *info,
    struct lima_job *job = lima_job_get(ctx);
    PLBU_CMD_BEGIN(&job->plbu_cmd_array, 32);
 
-   PLBU_CMD_VIEWPORT_LEFT(fui(ctx->viewport.left));
-   PLBU_CMD_VIEWPORT_RIGHT(fui(ctx->viewport.right));
-   PLBU_CMD_VIEWPORT_BOTTOM(fui(ctx->viewport.bottom));
-   PLBU_CMD_VIEWPORT_TOP(fui(ctx->viewport.top));
+   PLBU_CMD_VIEWPORT_LEFT(fui(ctx->ext_viewport.left));
+   PLBU_CMD_VIEWPORT_RIGHT(fui(ctx->ext_viewport.right));
+   PLBU_CMD_VIEWPORT_BOTTOM(fui(ctx->ext_viewport.bottom));
+   PLBU_CMD_VIEWPORT_TOP(fui(ctx->ext_viewport.top));
 
    if (!info->index_size)
       PLBU_CMD_ARRAYS_SEMAPHORE_BEGIN();
@@ -1171,6 +1197,10 @@ lima_draw_vbo(struct pipe_context *pctx,
    if (lima_is_scissor_zero(ctx))
       return;
 
+   /* extend the viewport in case of line draws with a line_width > 1.0f,
+    * otherwise use the original values */
+   lima_extend_viewport(ctx, info);
+
    if (!lima_update_fs_state(ctx) || !lima_update_vs_state(ctx))
       return;
 
diff --git a/src/gallium/drivers/lima/lima_state.c b/src/gallium/drivers/lima/lima_state.c
index 778c793fece..515e8f185c8 100644
--- a/src/gallium/drivers/lima/lima_state.c
+++ b/src/gallium/drivers/lima/lima_state.c
@@ -212,10 +212,14 @@ lima_set_viewport_states(struct pipe_context *pctx,
    struct lima_context *ctx = lima_context(pctx);
 
    /* reverse calculate the parameter of glViewport */
-   ctx->viewport.left = viewport->translate[0] - fabsf(viewport->scale[0]);
-   ctx->viewport.right = viewport->translate[0] + fabsf(viewport->scale[0]);
-   ctx->viewport.bottom = viewport->translate[1] - fabsf(viewport->scale[1]);
-   ctx->viewport.top = viewport->translate[1] + fabsf(viewport->scale[1]);
+   ctx->viewport.left = ctx->ext_viewport.left =
+      viewport->translate[0] - fabsf(viewport->scale[0]);
+   ctx->viewport.right = ctx->ext_viewport.right =
+      viewport->translate[0] + fabsf(viewport->scale[0]);
+   ctx->viewport.bottom = ctx->ext_viewport.bottom =
+      viewport->translate[1] - fabsf(viewport->scale[1]);
+   ctx->viewport.top = ctx->ext_viewport.top =
+      viewport->translate[1] + fabsf(viewport->scale[1]);
 
    /* reverse calculate the parameter of glDepthRange */
    float near, far;