[PATCH 2/3] glamor: Don't use PACK/UNPACK_SKIP_ROWS/PIXELS.

[Eric Anholt]

It's not available in GLES2 (though it's in GLES3).  It's trivial to
do the math, and avoids going through more switch statements in the GL
on desktop.

Signed-off-by: Eric Anholt <eric at anholt.net>
---
 glamor/glamor_transfer.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/glamor/glamor_transfer.c b/glamor/glamor_transfer.c
index 8914155..7a60c91 100644
--- a/glamor/glamor_transfer.c
+++ b/glamor/glamor_transfer.c
@@ -97,20 +97,16 @@ glamor_upload_boxes(PixmapPtr pixmap, BoxPtr in_boxes, int in_nbox,
             if (x2 <= x1 || y2 <= y1)
                 continue;
 
-            glPixelStorei(GL_UNPACK_SKIP_ROWS, y1 - dy_dst + dy_src);
-            glPixelStorei(GL_UNPACK_SKIP_PIXELS, x1 - dx_dst + dx_src);
-
             glTexSubImage2D(GL_TEXTURE_2D, 0,
                             x1 - box->x1, y1 - box->y1,
                             x2 - x1, y2 - y1,
                             format, type,
-                            bits);
+                            bits + ((y1 - dy_dst + dy_src) * byte_stride +
+                                    (x1 - dx_dst + dx_src) * bytes_per_pixel));
         }
     }
 
     glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
-    glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
-    glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
 }
 
 /*
@@ -189,14 +185,13 @@ glamor_download_boxes(PixmapPtr pixmap, BoxPtr in_boxes, int in_nbox,
             if (x2 <= x1 || y2 <= y1)
                 continue;
 
-            glPixelStorei(GL_PACK_SKIP_PIXELS, x1 - dx_src + dx_dst);
-            glPixelStorei(GL_PACK_SKIP_ROWS, y1 - dy_src + dy_dst);
-            glReadPixels(x1 - box->x1, y1 - box->y1, x2 - x1, y2 - y1, format, type, bits);
+            glReadPixels(x1 - box->x1, y1 - box->y1, x2 - x1, y2 - y1,
+                         format, type,
+                         bits + ((y1 - dy_src + dy_dst) * byte_stride +
+                                 (x1 - dx_src + dx_dst) * bytes_per_pixel));
         }
     }
     glPixelStorei(GL_PACK_ROW_LENGTH, 0);
-    glPixelStorei(GL_PACK_SKIP_ROWS, 0);
-    glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
 }
 
 /*
-- 
2.1.3