r300g: implement MSAA

This is not as optimized as r600g - the MSAA compression is missing,
so r300g needs a lot of bandwidth (more than r600g to do the same thing).
However, if the bandwidth is not an issue for you, you can enjoy this
unoptimized MSAA support.
The only other missing optimization for MSAA is the fast color clear.

MSAA is enabled on r500 only, because that's the only GPU family I tested.
That said, MSAA should work on r300 and r400 as well (but you must set
RADEON_MSAA=1 to allow it, then turn MSAA on in your app or set GALLIUM_MSAA=n,
n >= 2, n <= 6)
I will enable the support by default on r300-r400 once someone (other than me)
tests those chipsets with piglit.

The supported modes are 2x, 4x, 6x.

The supported MSAA formats are RGBA8, BGRA8, and RGBA16F (r500 only).
Those 3 formats are used for all GL internal formats.

Tested with piglit. (I have ported all MSAA tests to GL2.1)

1 files changed, 19 insertions, 18 deletions

diff --git a/src/gallium/drivers/r300/r300_texture_desc.c b/src/gallium/drivers/r300/r300_texture_desc.c
index 04d439b..9493eb1 100644
--- a/src/gallium/drivers/r300/r300_texture_desc.c
+++ b/src/gallium/drivers/r300/r300_texture_desc.c
@@ -56,7 +56,6 @@ unsigned r300_get_pixel_alignment(enum pipe_format format,
         }
     };
 
-    static const unsigned aa_block[2] = {4, 8};
     unsigned tile = 0;
     unsigned pixsize = util_format_get_blocksize(format);
 
@@ -65,22 +64,14 @@ unsigned r300_get_pixel_alignment(enum pipe_format format,
     assert(pixsize <= 16);
     assert(dim <= DIM_HEIGHT);
 
-    if (num_samples > 1) {
-        /* Multisampled textures have their own alignment scheme. */
-        if (pixsize == 4)
-            tile = aa_block[dim];
-        /* XXX FP16 AA. */
-    } else {
-        /* Standard alignment. */
-        tile = table[macrotile][util_logbase2(pixsize)][microtile][dim];
-        if (macrotile == 0 && is_rs690 && dim == DIM_WIDTH) {
-            int align;
-            int h_tile;
-            h_tile = table[macrotile][util_logbase2(pixsize)][microtile][DIM_HEIGHT];
-            align = 64 / (pixsize * h_tile);
-            if (tile < align)
-                tile = align;
-        }
+    tile = table[macrotile][util_logbase2(pixsize)][microtile][dim];
+    if (macrotile == 0 && is_rs690 && dim == DIM_WIDTH) {
+        int align;
+        int h_tile;
+        h_tile = table[macrotile][util_logbase2(pixsize)][microtile][DIM_HEIGHT];
+        align = 64 / (pixsize * h_tile);
+        if (tile < align)
+            tile = align;
     }
 
     assert(tile);
@@ -95,6 +86,10 @@ static boolean r300_texture_macro_switch(struct r300_resource *tex,
 {
     unsigned tile, texdim;
 
+    if (tex->b.b.nr_samples > 1) {
+        return TRUE;
+    }
+
     tile = r300_get_pixel_alignment(tex->b.b.format, tex->b.b.nr_samples,
                                     tex->tex.microtile, RADEON_LAYOUT_TILED, dim, 0);
     if (dim == DIM_WIDTH) {
@@ -248,7 +243,7 @@ static void r300_setup_miptree(struct r300_screen *screen,
 
         layer_size = stride * nblocksy;
 
-        if (base->nr_samples) {
+        if (base->nr_samples > 1) {
             layer_size *= base->nr_samples;
         }
 
@@ -423,6 +418,12 @@ static void r300_setup_tiling(struct r300_screen *screen,
     boolean is_zb = util_format_is_depth_or_stencil(format);
     boolean dbg_no_tiling = SCREEN_DBG_ON(screen, DBG_NO_TILING);
 
+    if (tex->b.b.nr_samples > 1) {
+        tex->tex.microtile = RADEON_LAYOUT_TILED;
+        tex->tex.macrotile[0] = RADEON_LAYOUT_TILED;
+        return;
+    }
+
     tex->tex.microtile = RADEON_LAYOUT_LINEAR;
     tex->tex.macrotile[0] = RADEON_LAYOUT_LINEAR;