radeon: r300 fix span reading for macro tiled buffers.

this uses the correct formula for macro tiled buffers for readback

1 files changed, 7 insertions, 6 deletions

diff --git a/src/mesa/drivers/dri/radeon/radeon_span.c b/src/mesa/drivers/dri/radeon/radeon_span.c
index 2530a82..2da931e 100644
--- a/src/mesa/drivers/dri/radeon/radeon_span.c
+++ b/src/mesa/drivers/dri/radeon/radeon_span.c
@@ -74,12 +74,13 @@ static GLubyte *radeon_ptr32(const struct radeon_renderbuffer * rrb,
                 offset += ((x & 31) >> 2) << 5;
                 offset += (x & 3) << 2;
             } else {
-                nmacroblkpl = rrb->pitch >> 6;
-                offset += ((y >> 3) * nmacroblkpl) << 11;
-                offset += (y & 7) << 8;
-                offset += (x >> 6) << 11;
-                offset += ((x & 63) >> 3) << 5;
-                offset += (x & 7) << 2;
+		offset = ((y >> 3) * (rrb->pitch >> 8) + (x >> 6)) << 11;
+		offset += (((y >> 2) ^ (x >> 6)) & 0x1) << 10;
+		offset += (((y >> 3) ^ (x >> 5)) & 0x1) << 9;
+		offset += (((y >> 1) ^ (x >> 5)) & 0x1) << 8;
+		offset += (((y >> 2) ^ (x >> 4)) & 0x1) << 7;
+		offset += (y & 1) << 6;
+		offset += (x & 15) << 2;
             }
         } else {
             nmicroblkpl = ((rrb->pitch + 31) & ~31) >> 5;