Mesa (master): r300g: optimize blending by discarding pixels that don' t change the colorbuffer
Corbin Simpson
csimpson at kemper.freedesktop.org
Wed Jan 6 20:49:32 UTC 2010
Module: Mesa
Branch: master
Commit: 6b9b3213c545644d155be54fd633e8b630a22465
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=6b9b3213c545644d155be54fd633e8b630a22465
Author: Marek Olšák <maraeo at gmail.com>
Date: Sun Dec 20 18:19:03 2009 +0100
r300g: optimize blending by discarding pixels that don't change the colorbuffer
Let's get some performance out of the blender.
---
src/gallium/drivers/r300/r300_state.c | 161 ++++++++++++++++++++++-
src/gallium/drivers/r300/r300_state_invariant.c | 4 +-
2 files changed, 162 insertions(+), 3 deletions(-)
diff --git a/src/gallium/drivers/r300/r300_state.c b/src/gallium/drivers/r300/r300_state.c
index 1dbf0bb..f8cce11 100644
--- a/src/gallium/drivers/r300/r300_state.c
+++ b/src/gallium/drivers/r300/r300_state.c
@@ -1,5 +1,6 @@
/*
* Copyright 2008 Corbin Simpson <MostAwesomeDude at gmail.com>
+ * Copyright 2009 Marek Olšák <maraeo at gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
@@ -41,6 +42,120 @@
/* r300_state: Functions used to intialize state context by translating
* Gallium state objects into semi-native r300 state objects. */
+static boolean blend_discard_if_src_alpha_0(unsigned srcRGB, unsigned srcA,
+ unsigned dstRGB, unsigned dstA)
+{
+ /* If the blend equation is ADD or REVERSE_SUBTRACT,
+ * SRC_ALPHA == 0, and the following state is set, the colorbuffer
+ * will not be changed.
+ * Notice that the dst factors are the src factors inverted. */
+ return (srcRGB == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ srcRGB == PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE ||
+ srcRGB == PIPE_BLENDFACTOR_ZERO) &&
+ (srcA == PIPE_BLENDFACTOR_SRC_COLOR ||
+ srcA == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ srcA == PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE ||
+ srcA == PIPE_BLENDFACTOR_ZERO) &&
+ (dstRGB == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ dstRGB == PIPE_BLENDFACTOR_ONE) &&
+ (dstA == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ dstA == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ dstA == PIPE_BLENDFACTOR_ONE);
+}
+
+static boolean blend_discard_if_src_alpha_1(unsigned srcRGB, unsigned srcA,
+ unsigned dstRGB, unsigned dstA)
+{
+ /* If the blend equation is ADD or REVERSE_SUBTRACT,
+ * SRC_ALPHA == 1, and the following state is set, the colorbuffer
+ * will not be changed.
+ * Notice that the dst factors are the src factors inverted. */
+ return (srcRGB == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ srcRGB == PIPE_BLENDFACTOR_ZERO) &&
+ (srcA == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ srcA == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ srcA == PIPE_BLENDFACTOR_ZERO) &&
+ (dstRGB == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ dstRGB == PIPE_BLENDFACTOR_ONE) &&
+ (dstA == PIPE_BLENDFACTOR_SRC_COLOR ||
+ dstA == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ dstA == PIPE_BLENDFACTOR_ONE);
+}
+
+static boolean blend_discard_if_src_color_0(unsigned srcRGB, unsigned srcA,
+ unsigned dstRGB, unsigned dstA)
+{
+ /* If the blend equation is ADD or REVERSE_SUBTRACT,
+ * SRC_COLOR == (0,0,0), and the following state is set, the colorbuffer
+ * will not be changed.
+ * Notice that the dst factors are the src factors inverted. */
+ return (srcRGB == PIPE_BLENDFACTOR_SRC_COLOR ||
+ srcRGB == PIPE_BLENDFACTOR_ZERO) &&
+ (srcA == PIPE_BLENDFACTOR_ZERO) &&
+ (dstRGB == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ dstRGB == PIPE_BLENDFACTOR_ONE) &&
+ (dstA == PIPE_BLENDFACTOR_ONE);
+}
+
+static boolean blend_discard_if_src_color_1(unsigned srcRGB, unsigned srcA,
+ unsigned dstRGB, unsigned dstA)
+{
+ /* If the blend equation is ADD or REVERSE_SUBTRACT,
+ * SRC_COLOR == (1,1,1), and the following state is set, the colorbuffer
+ * will not be changed.
+ * Notice that the dst factors are the src factors inverted. */
+ return (srcRGB == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ srcRGB == PIPE_BLENDFACTOR_ZERO) &&
+ (srcA == PIPE_BLENDFACTOR_ZERO) &&
+ (dstRGB == PIPE_BLENDFACTOR_SRC_COLOR ||
+ dstRGB == PIPE_BLENDFACTOR_ONE) &&
+ (dstA == PIPE_BLENDFACTOR_ONE);
+}
+
+static boolean blend_discard_if_src_alpha_color_0(unsigned srcRGB, unsigned srcA,
+ unsigned dstRGB, unsigned dstA)
+{
+ /* If the blend equation is ADD or REVERSE_SUBTRACT,
+ * SRC_ALPHA_COLOR == (0,0,0,0), and the following state is set,
+ * the colorbuffer will not be changed.
+ * Notice that the dst factors are the src factors inverted. */
+ return (srcRGB == PIPE_BLENDFACTOR_SRC_COLOR ||
+ srcRGB == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ srcRGB == PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE ||
+ srcRGB == PIPE_BLENDFACTOR_ZERO) &&
+ (srcA == PIPE_BLENDFACTOR_SRC_COLOR ||
+ srcA == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ srcA == PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE ||
+ srcA == PIPE_BLENDFACTOR_ZERO) &&
+ (dstRGB == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ dstRGB == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ dstRGB == PIPE_BLENDFACTOR_ONE) &&
+ (dstA == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ dstA == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ dstA == PIPE_BLENDFACTOR_ONE);
+}
+
+static boolean blend_discard_if_src_alpha_color_1(unsigned srcRGB, unsigned srcA,
+ unsigned dstRGB, unsigned dstA)
+{
+ /* If the blend equation is ADD or REVERSE_SUBTRACT,
+ * SRC_ALPHA_COLOR == (1,1,1,1), and the following state is set,
+ * the colorbuffer will not be changed.
+ * Notice that the dst factors are the src factors inverted. */
+ return (srcRGB == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ srcRGB == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ srcRGB == PIPE_BLENDFACTOR_ZERO) &&
+ (srcA == PIPE_BLENDFACTOR_INV_SRC_COLOR ||
+ srcA == PIPE_BLENDFACTOR_INV_SRC_ALPHA ||
+ srcA == PIPE_BLENDFACTOR_ZERO) &&
+ (dstRGB == PIPE_BLENDFACTOR_SRC_COLOR ||
+ dstRGB == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ dstRGB == PIPE_BLENDFACTOR_ONE) &&
+ (dstA == PIPE_BLENDFACTOR_SRC_COLOR ||
+ dstA == PIPE_BLENDFACTOR_SRC_ALPHA ||
+ dstA == PIPE_BLENDFACTOR_ONE);
+}
+
/* Create a new blend state based on the CSO blend state.
*
* This encompasses alpha blending, logic/raster ops, and blend dithering. */
@@ -86,7 +201,51 @@ static void* r300_create_blend_state(struct pipe_context* pipe,
srcRGB == PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE)
blend->blend_control |= R300_READ_ENABLE;
- /* XXX implement the optimization with DISCARD_SRC_PIXELS*/
+ /* Optimization: discard pixels which don't change the colorbuffer.
+ *
+ * The code below is non-trivial and some math is involved.
+ *
+ * Discarding pixels must be disabled when FP16 AA is enabled.
+ * This is a hardware bug. Also, this implementation wouldn't work
+ * with FP blending enabled and equation clamping disabled.
+ *
+ * Equations other than ADD are rarely used and therefore won't be
+ * optimized. */
+ if ((eqRGB == PIPE_BLEND_ADD || eqRGB == PIPE_BLEND_REVERSE_SUBTRACT) &&
+ (eqA == PIPE_BLEND_ADD || eqA == PIPE_BLEND_REVERSE_SUBTRACT)) {
+ /* ADD: X+Y
+ * REVERSE_SUBTRACT: Y-X
+ *
+ * The idea is:
+ * If X = src*srcFactor = 0 and Y = dst*dstFactor = 1,
+ * then CB will not be changed.
+ *
+ * Given the srcFactor and dstFactor variables, we can derive
+ * what src and dst should be equal to and discard appropriate
+ * pixels.
+ */
+ if (blend_discard_if_src_alpha_0(srcRGB, srcA, dstRGB, dstA)) {
+ blend->blend_control |= R300_DISCARD_SRC_PIXELS_SRC_ALPHA_0;
+ } else if (blend_discard_if_src_alpha_1(srcRGB, srcA,
+ dstRGB, dstA)) {
+ blend->blend_control |= R300_DISCARD_SRC_PIXELS_SRC_ALPHA_1;
+ } else if (blend_discard_if_src_color_0(srcRGB, srcA,
+ dstRGB, dstA)) {
+ blend->blend_control |= R300_DISCARD_SRC_PIXELS_SRC_COLOR_0;
+ } else if (blend_discard_if_src_color_1(srcRGB, srcA,
+ dstRGB, dstA)) {
+ blend->blend_control |= R300_DISCARD_SRC_PIXELS_SRC_COLOR_1;
+ } else if (blend_discard_if_src_alpha_color_0(srcRGB, srcA,
+ dstRGB, dstA)) {
+ blend->blend_control |=
+ R300_DISCARD_SRC_PIXELS_SRC_ALPHA_COLOR_0;
+ } else if (blend_discard_if_src_alpha_color_1(srcRGB, srcA,
+ dstRGB, dstA)) {
+ blend->blend_control |=
+ R300_DISCARD_SRC_PIXELS_SRC_ALPHA_COLOR_1;
+ }
+ }
+
/* XXX implement the optimization with SRC_ALPHA_?_NO_READ */
/* separate alpha */
diff --git a/src/gallium/drivers/r300/r300_state_invariant.c b/src/gallium/drivers/r300/r300_state_invariant.c
index bcd4c03..64dc14e 100644
--- a/src/gallium/drivers/r300/r300_state_invariant.c
+++ b/src/gallium/drivers/r300/r300_state_invariant.c
@@ -118,8 +118,8 @@ void r300_emit_invariant_state(struct r300_context* r300)
OUT_CS_REG(R300_SC_EDGERULE, 0x2DA49525);
OUT_CS_REG(R300_RB3D_AARESOLVE_CTL, 0x00000000);
if (caps->is_r500) {
- OUT_CS_REG(R500_RB3D_DISCARD_SRC_PIXEL_LTE_THRESHOLD, 0x00000000);
- OUT_CS_REG(R500_RB3D_DISCARD_SRC_PIXEL_GTE_THRESHOLD, 0xFFFFFFFF);
+ OUT_CS_REG(R500_RB3D_DISCARD_SRC_PIXEL_LTE_THRESHOLD, 0x01010101);
+ OUT_CS_REG(R500_RB3D_DISCARD_SRC_PIXEL_GTE_THRESHOLD, 0xFEFEFEFE);
}
OUT_CS_REG(R300_ZB_BW_CNTL, 0x00000000);
OUT_CS_REG(R300_ZB_DEPTHCLEARVALUE, 0x00000000);
More information about the mesa-commit
mailing list