glamor: * 1/size is faster than / size in VS

Pass the inverse of the texture size to glamor vertex shaders so that
we multiply by that instead of dividing by the size as multiplication
is generally faster than division.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>

4 files changed, 17 insertions, 17 deletions

diff --git a/glamor/glamor_copy.c b/glamor/glamor_copy.c
index e2d52041f..75fe8a700 100644
--- a/glamor/glamor_copy.c
+++ b/glamor/glamor_copy.c
@@ -42,7 +42,7 @@ use_copyarea(PixmapPtr dst, GCPtr gc, glamor_program *prog, void *arg)
     glBindTexture(GL_TEXTURE_2D, src->tex);
 
     glUniform2f(prog->fill_offset_uniform, args->dx, args->dy);
-    glUniform2f(prog->fill_size_uniform, src->width, src->height);
+    glUniform2f(prog->fill_size_inv_uniform, 1.0f/src->width, 1.0f/src->height);
 
     return TRUE;
 }
@@ -51,7 +51,7 @@ static const glamor_facet glamor_facet_copyarea = {
     "copy_area",
     .vs_vars = "attribute vec2 primitive;\n",
     .vs_exec = (GLAMOR_POS(gl_Position, primitive.xy)
-                "       fill_pos = (fill_offset + primitive.xy) / fill_size;\n"),
+                "       fill_pos = (fill_offset + primitive.xy) * fill_size_inv;\n"),
     .fs_exec = "       gl_FragColor = texture2D(sampler, fill_pos);\n",
     .locations = glamor_program_location_fill,
     .use = use_copyarea,
@@ -71,7 +71,7 @@ use_copyplane(PixmapPtr dst, GCPtr gc, glamor_program *prog, void *arg)
     glBindTexture(GL_TEXTURE_2D, src->tex);
 
     glUniform2f(prog->fill_offset_uniform, args->dx, args->dy);
-    glUniform2f(prog->fill_size_uniform, src->width, src->height);
+    glUniform2f(prog->fill_size_inv_uniform, 1.0f/src->width, 1.0f/src->height);
 
     glamor_set_color(dst, gc->fgPixel, prog->fg_uniform);
     glamor_set_color(dst, gc->bgPixel, prog->bg_uniform);
@@ -134,7 +134,7 @@ static const glamor_facet glamor_facet_copyplane = {
     .version = 130,
     .vs_vars = "attribute vec2 primitive;\n",
     .vs_exec = (GLAMOR_POS(gl_Position, (primitive.xy))
-                "       fill_pos = (fill_offset + primitive.xy) / fill_size;\n"),
+                "       fill_pos = (fill_offset + primitive.xy) * fill_size_inv;\n"),
     .fs_exec = ("       uvec4 bits = uvec4(round(texture2D(sampler, fill_pos) * bitmul));\n"
                 "       if ((bits & bitplane) != uvec4(0,0,0,0))\n"
                 "               gl_FragColor = fg;\n"
diff --git a/glamor/glamor_program.c b/glamor/glamor_program.c
index 3207aaf15..8aab53f4f 100644
--- a/glamor/glamor_program.c
+++ b/glamor/glamor_program.c
@@ -40,12 +40,12 @@ const glamor_facet glamor_fill_solid = {
 static Bool
 use_tile(PixmapPtr pixmap, GCPtr gc, glamor_program *prog, void *arg)
 {
-    return glamor_set_tiled(pixmap, gc, prog->fill_offset_uniform, prog->fill_size_uniform);
+    return glamor_set_tiled(pixmap, gc, prog->fill_offset_uniform, prog->fill_size_inv_uniform);
 }
 
 static const glamor_facet glamor_fill_tile = {
     .name = "tile",
-    .vs_exec =  "       fill_pos = (fill_offset + primitive.xy + pos) / fill_size;\n",
+    .vs_exec =  "       fill_pos = (fill_offset + primitive.xy + pos) * fill_size_inv;\n",
     .fs_exec =  "       gl_FragColor = texture2D(sampler, fill_pos);\n",
     .locations = glamor_program_location_fill,
     .use = use_tile,
@@ -56,12 +56,12 @@ use_stipple(PixmapPtr pixmap, GCPtr gc, glamor_program *prog, void *arg)
 {
     return glamor_set_stippled(pixmap, gc, prog->fg_uniform,
                                prog->fill_offset_uniform,
-                               prog->fill_size_uniform);
+                               prog->fill_size_inv_uniform);
 }
 
 static const glamor_facet glamor_fill_stipple = {
     .name = "stipple",
-    .vs_exec =  "       fill_pos = (fill_offset + primitive.xy + pos) / fill_size;\n",
+    .vs_exec =  "       fill_pos = (fill_offset + primitive.xy + pos) * fill_size_inv;\n",
     .fs_exec = ("       float a = texture2D(sampler, fill_pos).w;\n"
                 "       if (a == 0.0)\n"
                 "               discard;\n"
@@ -81,7 +81,7 @@ use_opaque_stipple(PixmapPtr pixmap, GCPtr gc, glamor_program *prog, void *arg)
 
 static const glamor_facet glamor_fill_opaque_stipple = {
     .name = "opaque_stipple",
-    .vs_exec =  "       fill_pos = (fill_offset + primitive.xy + pos) / fill_size;\n",
+    .vs_exec =  "       fill_pos = (fill_offset + primitive.xy + pos) * fill_size_inv;\n",
     .fs_exec = ("       float a = texture2D(sampler, fill_pos).w;\n"
                 "       if (a == 0.0)\n"
                 "               gl_FragColor = bg;\n"
@@ -116,10 +116,10 @@ static glamor_location_var location_vars[] = {
     {
         .location = glamor_program_location_fill,
         .vs_vars = ("uniform vec2 fill_offset;\n"
-                    "uniform vec2 fill_size;\n"
+                    "uniform vec2 fill_size_inv;\n"
                     "varying vec2 fill_pos;\n"),
         .fs_vars = ("uniform sampler2D sampler;\n"
-                    "uniform vec2 fill_size;\n"
+                    "uniform vec2 fill_size_inv;\n"
                     "varying vec2 fill_pos;\n")
     },
     {
@@ -336,7 +336,7 @@ glamor_build_program(ScreenPtr          screen,
     prog->fg_uniform = glamor_get_uniform(prog, glamor_program_location_fg, "fg");
     prog->bg_uniform = glamor_get_uniform(prog, glamor_program_location_bg, "bg");
     prog->fill_offset_uniform = glamor_get_uniform(prog, glamor_program_location_fill, "fill_offset");
-    prog->fill_size_uniform = glamor_get_uniform(prog, glamor_program_location_fill, "fill_size");
+    prog->fill_size_inv_uniform = glamor_get_uniform(prog, glamor_program_location_fill, "fill_size_inv");
     prog->font_uniform = glamor_get_uniform(prog, glamor_program_location_font, "font");
     prog->bitplane_uniform = glamor_get_uniform(prog, glamor_program_location_bitplane, "bitplane");
     prog->bitmul_uniform = glamor_get_uniform(prog, glamor_program_location_bitplane, "bitmul");
diff --git a/glamor/glamor_program.h b/glamor/glamor_program.h
index 56ba03aa8..fa3877c5d 100644
--- a/glamor/glamor_program.h
+++ b/glamor/glamor_program.h
@@ -60,7 +60,7 @@ struct _glamor_program {
     GLint                       matrix_uniform;
     GLint                       fg_uniform;
     GLint                       bg_uniform;
-    GLint                       fill_size_uniform;
+    GLint                       fill_size_inv_uniform;
     GLint                       fill_offset_uniform;
     GLint                       font_uniform;
     GLint                       bitplane_uniform;
diff --git a/glamor/glamor_transform.c b/glamor/glamor_transform.c
index df45b6fa4..6d29e9eb6 100644
--- a/glamor/glamor_transform.c
+++ b/glamor/glamor_transform.c
@@ -160,7 +160,7 @@ glamor_set_texture(PixmapPtr    pixmap,
                    int          off_x,
                    int          off_y,
                    GLint        offset_uniform,
-                   GLint        size_uniform)
+                   GLint        size_inv_uniform)
 {
     glamor_pixmap_private *texture_priv;
 
@@ -176,7 +176,7 @@ glamor_set_texture(PixmapPtr    pixmap,
     glBindTexture(GL_TEXTURE_2D, texture_priv->fbo->tex);
 
     glUniform2f(offset_uniform, off_x, off_y);
-    glUniform2f(size_uniform, texture->drawable.width, texture->drawable.height);
+    glUniform2f(size_inv_uniform, 1.0f/texture->drawable.width, 1.0f/texture->drawable.height);
     return TRUE;
 }
 
@@ -184,7 +184,7 @@ Bool
 glamor_set_tiled(PixmapPtr      pixmap,
                  GCPtr          gc,
                  GLint          offset_uniform,
-                 GLint          size_uniform)
+                 GLint          size_inv_uniform)
 {
     if (!glamor_set_alu(pixmap->drawable.pScreen, gc->alu))
         return FALSE;
@@ -197,7 +197,7 @@ glamor_set_tiled(PixmapPtr      pixmap,
                               -gc->patOrg.x,
                               -gc->patOrg.y,
                               offset_uniform,
-                              size_uniform);
+                              size_inv_uniform);
 }
 
 static PixmapPtr