glamor: Add glamor_program based 0-width dashed lines

This makes sure the pixelization for dashed lines matches non-dashed
lines, while also speeding them up.

v2: Switch to glamor_make_current

v3: Create dash pattern pixmap without GLAMOR_CREATE_FBO_NO_FBO

v4: Adopt suggestions from Eric's review:

  - Drops power-of-two alignment of our line vertex data, simplifying
    the code.

  - Stops reading from the VBO.  While on keithp's and my machines the
    VBO is mapped cached, on many implementations it will be mapped WC,
    making those reads extremely expensive.

  - Style fixes (line wrapping, spaces around operators).

v5: Adopt suggestions from Markus' review:

  - Use max when computing zero-width dashed line length.

    Don't open code max here.

  - Embed CoordModePrevious into VBO writing for dashed lines

    Instead of pre-computing the coord mode previous results, just
    embed this in the loop which fills the vertex buffer. Saves
    re-writing the request buffer, and shortens the code a bit

v6: Export glamor_destroy_gc for UXA

    UXA needs to call glamor_destroy_gc from its GCFuncs, so export
    it.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

1 files changed, 28 insertions, 1 deletions

diff --git a/glamor/glamor_priv.h b/glamor/glamor_priv.h
index 07e1b890f..6480eb607 100644
--- a/glamor/glamor_priv.h
+++ b/glamor/glamor_priv.h
@@ -247,6 +247,10 @@ typedef struct glamor_screen_private {
     /* glamor segment shaders */
     glamor_program_fill poly_segment_program;
 
+    /*  glamor dash line shader */
+    glamor_program_fill on_off_dash_line_progs;
+    glamor_program      double_dash_line_prog;
+
     /* vertext/elment_index buffer object for render */
     GLuint vbo, ebo;
     /** Next offset within the VBO that glamor_get_vbo_space() will use. */
@@ -559,6 +563,13 @@ typedef enum glamor_pixmap_status {
     GLAMOR_UPLOAD_FAILED
 } glamor_pixmap_status_t;
 
+/* GC private structure. Currently holds only any computed dash pixmap */
+
+typedef struct {
+    PixmapPtr   dash;
+} glamor_gc_private;
+
+extern DevPrivateKeyRec glamor_gc_private_key;
 extern DevPrivateKeyRec glamor_screen_private_key;
 extern DevPrivateKeyRec glamor_pixmap_private_key;
 
@@ -591,6 +602,12 @@ glamor_get_pixmap_private(PixmapPtr pixmap)
 
 void glamor_set_pixmap_private(PixmapPtr pixmap, glamor_pixmap_private *priv);
 
+static inline glamor_gc_private *
+glamor_get_gc_private(GCPtr gc)
+{
+    return dixLookupPrivate(&gc->devPrivates, &glamor_gc_private_key);
+}
+
 /**
  * Returns TRUE if the given planemask covers all the significant bits in the
  * pixel values for pDrawable.
@@ -969,7 +986,17 @@ glamor_put_image(DrawablePtr drawable, GCPtr gc, int depth, int x, int y,
 void
 glamor_get_image(DrawablePtr pDrawable, int x, int y, int w, int h,
                  unsigned int format, unsigned long planeMask, char *d);
-/*  glamor_lines.c */
+
+/* glamor_dash.c */
+Bool
+glamor_poly_lines_dash_gl(DrawablePtr drawable, GCPtr gc,
+                          int mode, int n, DDXPointPtr points);
+
+Bool
+glamor_poly_segment_dash_gl(DrawablePtr drawable, GCPtr gc,
+                            int nseg, xSegment *segs);
+
+/* glamor_lines.c */
 void
 glamor_poly_lines(DrawablePtr drawable, GCPtr gc,
                   int mode, int n, DDXPointPtr points);