From 77a7f02a91112f0092a85247586de58e938731fc Mon Sep 17 00:00:00 2001 From: Neil Roberts Date: Sun, 26 Feb 2012 01:33:40 +0000 Subject: [PATCH 1/2] readpix: Don't disable fast path for normalized types Mesa has a fast path for the generic fallback when using glReadPixels for RGBA data which uses memcpy. However it was really difficult to hit this case because it would not be used if any transferOps are enabled. Any type apart from floating point or non-normalized integer types (so any of the common types) would force enabling clamping so the fast path could not be used. This patch makes it ignore clamping when determining whether to use the fast path if the data type of the buffer is an unsigned normalized type because in that case clamping will not have any effect anyway. https://bugs.freedesktop.org/show_bug.cgi?id=46631 --- src/mesa/main/readpix.c | 21 ++++++++++++++------- 1 files changed, 14 insertions(+), 7 deletions(-) diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c index 0f429ab..cddab43 100644 --- a/src/mesa/main/readpix.c +++ b/src/mesa/main/readpix.c @@ -225,6 +225,15 @@ fast_read_rgba_pixels_memcpy( struct gl_context *ctx, ctx->Pack.SwapBytes)) return GL_FALSE; + /* If the format is unsigned normalized then we can ignore clamping + because the values are already in the range 0->1 so it won't + have any effect anyway */ + if (_mesa_get_format_datatype(rb->Format) == GL_UNSIGNED_NORMALIZED) + transferOps &= ~IMAGE_CLAMP_BIT; + + if (transferOps) + return GL_FALSE; + dstStride = _mesa_image_row_stride(packing, width, format, type); dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height, format, type, 0, 0); @@ -320,13 +329,11 @@ read_rgba_pixels( struct gl_context *ctx, transferOps |= IMAGE_CLAMP_BIT; } - if (!transferOps) { - /* Try the optimized paths first. */ - if (fast_read_rgba_pixels_memcpy(ctx, x, y, width, height, - format, type, pixels, packing, - transferOps)) { - return; - } + /* Try the optimized paths first. */ + if (fast_read_rgba_pixels_memcpy(ctx, x, y, width, height, + format, type, pixels, packing, + transferOps)) { + return; } slow_read_rgba_pixels(ctx, x, y, width, height, -- 1.7.3.16.g9464b