[PATCH 22/27] glamor: Improve the performance of PolyGlyphBlt.

[Eric Anholt]

Using the same idea as the previous PushPixels code, just make points
for each point in the glyph.  This is an advantage over the pushpixels
fallback because we can batch the BO mappings and draw calls across
glyphs.

Improves performance of x11perf -f8text by 773.389% +/- 3.50754% (n=10).

Signed-off-by: Eric Anholt <eric at anholt.net>
---
 glamor/glamor_glyphblt.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)

diff --git a/glamor/glamor_glyphblt.c b/glamor/glamor_glyphblt.c
index 0a99a95..5d785a0 100644
--- a/glamor/glamor_glyphblt.c
+++ b/glamor/glamor_glyphblt.c
@@ -27,6 +27,141 @@
  */
 
 #include "glamor_priv.h"
+#include <dixfontstr.h>
+
+static Bool
+glamor_poly_glyph_blt_pixels(DrawablePtr drawable, GCPtr gc,
+                             int x, int y, unsigned int nglyph,
+                             CharInfoPtr *ppci)
+{
+    ScreenPtr screen = drawable->pScreen;
+    glamor_screen_private *glamor_priv = glamor_get_screen_private(screen);
+    PixmapPtr pixmap = glamor_get_drawable_pixmap(drawable);
+    glamor_pixmap_private *pixmap_priv;
+    int off_x, off_y;
+    GLfloat xscale, yscale;
+    float color[4];
+    unsigned long fg_pixel = gc->fgPixel;
+    char *vbo_offset;
+    RegionPtr clip;
+    int num_points, max_points;
+    float *points = NULL;
+
+    x += drawable->x;
+    y += drawable->y;
+
+    if (gc->fillStyle != FillSolid) {
+        glamor_fallback("gc fillstyle not solid\n");
+        return FALSE;
+    }
+
+    pixmap_priv = glamor_get_pixmap_private(pixmap);
+    if (!GLAMOR_PIXMAP_PRIV_HAS_FBO(pixmap_priv))
+        return FALSE;
+
+    glamor_get_context(glamor_priv);
+    if (!glamor_set_alu(screen, gc->alu)) {
+        if (gc->alu == GXclear)
+            fg_pixel = 0;
+        else {
+            glamor_fallback("unsupported alu %x\n", gc->alu);
+            glamor_put_context(glamor_priv);
+            return FALSE;
+        }
+    }
+
+    if (!glamor_set_planemask(pixmap, gc->planemask)) {
+        glamor_fallback("Failed to set planemask in %s.\n", __FUNCTION__);
+        glamor_put_context(glamor_priv);
+        return FALSE;
+    }
+
+    glamor_get_drawable_deltas(drawable, pixmap, &off_x, &off_y);
+
+    glamor_set_destination_pixmap_priv_nc(pixmap_priv);
+    pixmap_priv_get_dest_scale(pixmap_priv, &xscale, &yscale);
+
+    glUseProgram(glamor_priv->solid_prog);
+
+    glamor_get_rgba_from_pixel(fg_pixel,
+                               &color[0], &color[1], &color[2], &color[3],
+                               format_for_pixmap(pixmap));
+    glUniform4fv(glamor_priv->solid_color_uniform_location, 1, color);
+
+    clip = fbGetCompositeClip(gc);
+
+    glEnableVertexAttribArray(GLAMOR_VERTEX_POS);
+
+    max_points = 500;
+    num_points = 0;
+    while (nglyph--) {
+        CharInfoPtr charinfo = *ppci++;
+        int w = GLYPHWIDTHPIXELS(charinfo);
+        int h = GLYPHHEIGHTPIXELS(charinfo);
+        uint8_t *glyphbits = FONTGLYPHBITS(NULL, charinfo);
+
+        if (w && h) {
+            int glyph_x = x + charinfo->metrics.leftSideBearing;
+            int glyph_y = y - charinfo->metrics.ascent;
+            int glyph_stride = GLYPHWIDTHBYTESPADDED(charinfo);
+            int xx, yy;
+
+            for (yy = 0; yy < h; yy++) {
+                uint8_t *glyph_row = glyphbits + glyph_stride * yy;
+                for (xx = 0; xx < w; xx++) {
+                    int pt_x_i = glyph_x + xx;
+                    int pt_y_i = glyph_y + yy;
+                    float pt_x_f, pt_y_f;
+                    if (!(glyph_row[xx / 8] & (1 << xx % 8)))
+                        continue;
+
+                    if (!RegionContainsPoint(clip, pt_x_i, pt_y_i, NULL))
+                        continue;
+
+                    if (!num_points) {
+                        points = glamor_get_vbo_space(screen,
+                                                      max_points * 2 * sizeof(float),
+                                                      &vbo_offset);
+
+                        glVertexAttribPointer(GLAMOR_VERTEX_POS, 2, GL_FLOAT,
+                                              GL_FALSE, 2 * sizeof(float),
+                                              vbo_offset);
+                    }
+
+                    pt_x_f = v_from_x_coord_x(xscale, pt_x_i + off_x + 0.5);
+                    if (glamor_priv->yInverted)
+                        pt_y_f = v_from_x_coord_y_inverted(yscale, pt_y_i + off_y + 0.5);
+                    else
+                        pt_y_f = v_from_x_coord_y(yscale, pt_y_i + off_y + 0.5);
+
+                    points[num_points * 2 + 0] = pt_x_f;
+                    points[num_points * 2 + 1] = pt_y_f;
+                    num_points++;
+
+                    if (num_points == max_points) {
+                        glamor_put_vbo_space(screen);
+                        glDrawArrays(GL_POINTS, 0, num_points);
+                        num_points = 0;
+                    }
+                }
+            }
+        }
+
+        x += charinfo->metrics.characterWidth;
+    }
+
+    if (num_points) {
+        glamor_put_vbo_space(screen);
+        glDrawArrays(GL_POINTS, 0, num_points);
+    }
+
+    glDisableVertexAttribArray(GLAMOR_VERTEX_POS);
+    glUseProgram(0);
+
+    glamor_put_context(glamor_priv);
+
+    return TRUE;
+}
 
 static Bool
 _glamor_image_glyph_blt(DrawablePtr pDrawable, GCPtr pGC,
@@ -64,6 +199,9 @@ _glamor_poly_glyph_blt(DrawablePtr pDrawable, GCPtr pGC,
                        int x, int y, unsigned int nglyph,
                        CharInfoPtr *ppci, void *pglyphBase, Bool fallback)
 {
+    if (glamor_poly_glyph_blt_pixels(pDrawable, pGC, x, y, nglyph, ppci))
+        return TRUE;
+
     if (!fallback && glamor_ddx_fallback_check_pixmap(pDrawable)
         && glamor_ddx_fallback_check_gc(pGC))
         return FALSE;
-- 
1.9.0