From a7504ad587ee8cbfa9958ad23321a691ce0823d3 Mon Sep 17 00:00:00 2001 From: Brian Date: Wed, 2 Apr 2008 14:30:28 -0600 Subject: [PATCH] cell: added some comments/ideas about better texture sampling --- src/gallium/drivers/cell/spu/spu_texture.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/src/gallium/drivers/cell/spu/spu_texture.c b/src/gallium/drivers/cell/spu/spu_texture.c index e9a2754e571..5051774f00c 100644 --- a/src/gallium/drivers/cell/spu/spu_texture.c +++ b/src/gallium/drivers/cell/spu/spu_texture.c @@ -48,9 +48,16 @@ invalidate_tex_cache(void) } +/** + * XXX look into getting texels for all four pixels in a quad at once. + */ static uint get_texel(uint unit, vec_uint4 coordinate) { + /* + * XXX we could do the "/ TILE_SIZE" and "% TILE_SIZE" operations as + * SIMD since X and Y are already in a SIMD register. + */ const unsigned texture_ea = (uintptr_t) spu.texture[unit].start; ushort x = spu_extract(coordinate, 0); ushort y = spu_extract(coordinate, 1); @@ -69,6 +76,16 @@ get_texel(uint unit, vec_uint4 coordinate) /** * Get four texels from locations (x[0], y[0]), (x[1], y[1]) ... + * + * NOTE: in the typical case of bilinear filtering, the four texels + * are in a 2x2 group so we could get by with just two dcache fetches + * (two side-by-side texels per fetch). But when bilinear filtering + * wraps around a texture edge, we'll probably need code like we have + * now. + * FURTHERMORE: since we're rasterizing a quad of 2x2 pixels at a time, + * it's quite likely that the four pixels in a quad will need some of the + * same texels. So look into doing texture fetches for four pixels at + * a time. */ static void get_four_texels(uint unit, vec_uint4 x, vec_uint4 y, vec_uint4 *texels) @@ -103,7 +120,6 @@ get_four_texels(uint unit, vec_uint4 x, vec_uint4 y, vec_uint4 *texels) /** * Get texture sample at texcoord. - * XXX this is extremely primitive for now. */ vector float sample_texture_nearest(uint unit, vector float texcoord) -- 2.30.2