draw: fix splitting of line loops (v2)

When the draw module splits long line loops, the sections are emitted
as line strips.  But the primitive type wasn't set correctly so each
section was being drawn as a loop, introducing extra line segments.

To fix this, we pass a new DRAW_LINE_LOOP_AS_STRIP flag to the run()
function.  The linear/elt_run() functions have to check for this flag
and set their primitive type accordingly.

No piglit regressions.  Fixes piglit's lineloop with -count 4097 or
higher.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81174

Reviewed-by: Roland Scheidegger <sroland@vmware.com>

diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index 0ad94bb031f3d094559ae13a7002ae57556d3831..5584c4a222c5e28a04f3299dc12e32b326b611c2 100644 (file)
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -355,8 +355,9 @@ struct draw_vertex_info {
 };
 
 /* these flags are set if the primitive is a segment of a larger one */
-#define DRAW_SPLIT_BEFORE 0x1
-#define DRAW_SPLIT_AFTER  0x2
+#define DRAW_SPLIT_BEFORE        0x1
+#define DRAW_SPLIT_AFTER         0x2
+#define DRAW_LINE_LOOP_AS_STRIP  0x4
 
 struct draw_prim_info {
    boolean linear;

diff --git a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c
index ffec863ae6fcdae2675816f94386edd676cb6b0b..aa20b918f50a321db4397e791f48b9ff2d79a7fd 100644 (file)
--- a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c
+++ b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c
@@ -359,6 +359,16 @@ fetch_pipeline_generic(struct draw_pt_middle_end *middle,
 }
 
 
+static inline unsigned
+prim_type(unsigned prim, unsigned flags)
+{
+   if (flags & DRAW_LINE_LOOP_AS_STRIP)
+      return PIPE_PRIM_LINE_STRIP;
+   else
+      return prim;
+}
+
+
 static void
 fetch_pipeline_run(struct draw_pt_middle_end *middle,
                    const unsigned *fetch_elts,
@@ -380,7 +390,7 @@ fetch_pipeline_run(struct draw_pt_middle_end *middle,
    prim_info.start = 0;
    prim_info.count = draw_count;
    prim_info.elts = draw_elts;
-   prim_info.prim = fpme->input_prim;
+   prim_info.prim = prim_type(fpme->input_prim, prim_flags);
    prim_info.flags = prim_flags;
    prim_info.primitive_count = 1;
    prim_info.primitive_lengths = &draw_count;
@@ -408,7 +418,7 @@ fetch_pipeline_linear_run(struct draw_pt_middle_end *middle,
    prim_info.start = 0;
    prim_info.count = count;
    prim_info.elts = NULL;
-   prim_info.prim = fpme->input_prim;
+   prim_info.prim = prim_type(fpme->input_prim, prim_flags);
    prim_info.flags = prim_flags;
    prim_info.primitive_count = 1;
    prim_info.primitive_lengths = &count;
@@ -439,7 +449,7 @@ fetch_pipeline_linear_run_elts(struct draw_pt_middle_end *middle,
    prim_info.start = 0;
    prim_info.count = draw_count;
    prim_info.elts = draw_elts;
-   prim_info.prim = fpme->input_prim;
+   prim_info.prim = prim_type(fpme->input_prim, prim_flags);
    prim_info.flags = prim_flags;
    prim_info.primitive_count = 1;
    prim_info.primitive_lengths = &draw_count;

diff --git a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
index e42c4af0e70726672d09444905a73d98b5ffb3a2..2d7569b0fdf7c4c8627a80c46213ac0cea1b12d8 100644 (file)
--- a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
@@ -473,6 +473,16 @@ llvm_pipeline_generic(struct draw_pt_middle_end *middle,
 }
 
 
+static inline unsigned
+prim_type(unsigned prim, unsigned flags)
+{
+   if (flags & DRAW_LINE_LOOP_AS_STRIP)
+      return PIPE_PRIM_LINE_STRIP;
+   else
+      return prim;
+}
+
+
 static void
 llvm_middle_end_run(struct draw_pt_middle_end *middle,
                     const unsigned *fetch_elts,
@@ -494,7 +504,7 @@ llvm_middle_end_run(struct draw_pt_middle_end *middle,
    prim_info.start = 0;
    prim_info.count = draw_count;
    prim_info.elts = draw_elts;
-   prim_info.prim = fpme->input_prim;
+   prim_info.prim = prim_type(fpme->input_prim, prim_flags);
    prim_info.flags = prim_flags;
    prim_info.primitive_count = 1;
    prim_info.primitive_lengths = &draw_count;
@@ -522,7 +532,7 @@ llvm_middle_end_linear_run(struct draw_pt_middle_end *middle,
    prim_info.start = 0;
    prim_info.count = count;
    prim_info.elts = NULL;
-   prim_info.prim = fpme->input_prim;
+   prim_info.prim = prim_type(fpme->input_prim, prim_flags);
    prim_info.flags = prim_flags;
    prim_info.primitive_count = 1;
    prim_info.primitive_lengths = &count;
@@ -552,7 +562,7 @@ llvm_middle_end_linear_run_elts(struct draw_pt_middle_end *middle,
    prim_info.start = 0;
    prim_info.count = draw_count;
    prim_info.elts = draw_elts;
-   prim_info.prim = fpme->input_prim;
+   prim_info.prim = prim_type(fpme->input_prim, prim_flags);
    prim_info.flags = prim_flags;
    prim_info.primitive_count = 1;
    prim_info.primitive_lengths = &draw_count;

diff --git a/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h b/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h
index 0afabb013984c944f0c92533ef7f769f087d7faa..6da79b9490b9dfccf4c7719bc0bd37e729688e60 100644 (file)
--- a/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h
+++ b/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h
@@ -249,6 +249,9 @@ vsplit_segment_loop_linear(struct vsplit_frontend *vsplit, unsigned flags,
 
    assert(icount + !!close_loop <= vsplit->segment_size);
 
+   /* need to draw the sections of the line loop as line strips */
+   flags |= DRAW_LINE_LOOP_AS_STRIP;
+
    if (close_loop) {
       for (nr = 0; nr < icount; nr++)
          vsplit->fetch_elts[nr] = istart + nr;