From 8c3c8bda2c44fb3d62b954b02b08e3b1771ef5bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <mdaenzer@redhat.com>
Date: Tue, 25 Aug 2020 17:26:56 +0200
Subject: [PATCH xserver 05/16] glamor: Fix glamor_poly_fill_rect_gl
 xRectangle::width/height handling

(Using GLSL 1.30 or newer)

The width/height members of xRectangle are unsigned, but they were
being interpreted as signed when converting to floating point for the
vertex shader, producing incorrect drawing for values > 32767.

v2:
* Use separate GL_UNSIGNED_SHORT vertex attribute for width/height.
  (Eric Anholt)

Reviewed-by: Eric Anholt <eric@anholt.net>
(cherry picked from commit 032af35657aa95c6bbdb74ff8c72e535b9b56cfa)
---
 glamor/glamor_rects.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/glamor/glamor_rects.c b/glamor/glamor_rects.c
index 6cbb040c1..ae4fe8bcc 100644
--- a/glamor/glamor_rects.c
+++ b/glamor/glamor_rects.c
@@ -27,8 +27,10 @@
 static const glamor_facet glamor_facet_polyfillrect_130 = {
     .name = "poly_fill_rect",
     .version = 130,
-    .vs_vars = "attribute vec4 primitive;\n",
-    .vs_exec = ("       vec2 pos = primitive.zw * vec2(gl_VertexID&1, (gl_VertexID&2)>>1);\n"
+    .source_name = "size",
+    .vs_vars = "attribute vec2 primitive;\n"
+               "attribute vec2 size;\n",
+    .vs_exec = ("       vec2 pos = size * vec2(gl_VertexID&1, (gl_VertexID&2)>>1);\n"
                 GLAMOR_POS(gl_Position, (primitive.xy + pos))),
 };
 
@@ -81,9 +83,14 @@ glamor_poly_fill_rect_gl(DrawablePtr drawable,
 
         glEnableVertexAttribArray(GLAMOR_VERTEX_POS);
         glVertexAttribDivisor(GLAMOR_VERTEX_POS, 1);
-        glVertexAttribPointer(GLAMOR_VERTEX_POS, 4, GL_SHORT, GL_FALSE,
+        glVertexAttribPointer(GLAMOR_VERTEX_POS, 2, GL_SHORT, GL_FALSE,
                               4 * sizeof (short), vbo_offset);
 
+        glEnableVertexAttribArray(GLAMOR_VERTEX_SOURCE);
+        glVertexAttribDivisor(GLAMOR_VERTEX_SOURCE, 1);
+        glVertexAttribPointer(GLAMOR_VERTEX_SOURCE, 2, GL_UNSIGNED_SHORT, GL_FALSE,
+                              4 * sizeof (short), vbo_offset + 2 * sizeof (short));
+
         memcpy(v, prect, nrect * sizeof (xRectangle));
 
         glamor_put_vbo_space(screen);
@@ -156,8 +163,11 @@ glamor_poly_fill_rect_gl(DrawablePtr drawable,
 
 bail:
     glDisable(GL_SCISSOR_TEST);
-    if (glamor_priv->glsl_version >= 130)
+    if (glamor_priv->glsl_version >= 130) {
+        glVertexAttribDivisor(GLAMOR_VERTEX_SOURCE, 0);
+        glDisableVertexAttribArray(GLAMOR_VERTEX_SOURCE);
         glVertexAttribDivisor(GLAMOR_VERTEX_POS, 0);
+    }
     glDisableVertexAttribArray(GLAMOR_VERTEX_POS);
 
     return ret;
-- 
2.28.0