From 329cd6a9b145d5b3b5a2acca1b6c2019d01c9355 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Thu, 20 Jun 2013 05:43:32 -0700 Subject: [PATCH] i965: Be more careful with the interleaved user array upload optimization The checks to determine when the data can be uploaded in an interleaved fashion can be tricked by certain data layouts. For example, float data[...]; glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 16, &data[0]); glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 16, &data[4]); glDrawArrays(GL_POINTS, 0, 1); will hit the interleaved path with an incorrect size (16 bytes instead of 32 bytes). As a result, the data for attribute 1 never gets uploaded. The single element draw case is the only sensible case I can think of for non-interleaved-that-looks-like-interleaved data, but there may be others as well. To fix this, make sure that the end of the element in the array being checked is within the stride "window." Previously the code would check that the begining of the element was within the window. NOTE: This is a candidate for stable branches. Signed-off-by: Ian Romanick Reviewed-by: Eric Anholt Acked-by: Kenneth Graunke --- src/mesa/drivers/dri/i965/brw_draw_upload.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c index 2ded14b0de7..74c9e2f40d4 100644 --- a/src/mesa/drivers/dri/i965/brw_draw_upload.c +++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c @@ -506,8 +506,24 @@ static void brw_prepare_vertices(struct brw_context *brw) ptr = glarray->Ptr; } else if (interleaved != glarray->StrideB || - (uintptr_t)(glarray->Ptr - ptr) > interleaved) + glarray->Ptr < ptr || + (uintptr_t)(glarray->Ptr - ptr) + glarray->_ElementSize > interleaved) { + /* If our stride is different from the first attribute's stride, + * or if the first attribute's stride didn't cover our element, + * disable the interleaved upload optimization. The second case + * can most commonly occur in cases where there is a single vertex + * and, for example, the data is stored on the application's + * stack. + * + * NOTE: This will also disable the optimization in cases where + * the data is in a different order than the array indices. + * Something like: + * + * float data[...]; + * glVertexAttribPointer(0, 4, GL_FLOAT, 32, &data[4]); + * glVertexAttribPointer(1, 4, GL_FLOAT, 32, &data[0]); + */ interleaved = 0; } -- 2.30.2