r300g: add high quality anisotropic filtering for R5xx (disabled by default)

Oh look, an undocumented feature. It's a nice tool for benchmarking
texturing.

src/gallium/drivers/r300/r300_debug.c

@@ -37,6 +37,7 @@ static struct debug_option debug_options[] = {
     { "draw", DBG_DRAW, "Draw and emit" },
     { "tex", DBG_TEX, "Textures" },
     { "fall", DBG_FALL, "Fallbacks" },
+    { "anisohq", DBG_ANISOHQ, "High quality anisotropic filtering (for benchmarking purposes only!)" },
 
     { "all", ~0, "Convenience option that enables all debug flags" },
 

src/gallium/drivers/r300/r300_reg.h

@@ -1500,6 +1500,10 @@ USE OR OTHER DEALINGS IN THE SOFTWARE.
 #	define R300_ANISO_THRESHOLD_MASK       (7<<17)
 
 #	define R500_MACRO_SWITCH               (1<<22)
+#       define R500_TX_MAX_ANISO(x)            ((x) << 23)
+#       define R500_TX_MAX_ANISO_MASK          (63 << 23)
+#       define R500_TX_ANISO_HIGH_QUALITY      (1 << 30)
+
 #	define R500_BORDER_FIX                 (1<<31)
 
 #define R300_TX_FORMAT0_0                   0x4480

src/gallium/drivers/r300/r300_screen.h

@@ -77,6 +77,7 @@ struct pipe_screen* r300_create_screen(struct radeon_winsys* radeon_winsys);
 #define DBG_DRAW    0x0000010
 #define DBG_TEX     0x0000020
 #define DBG_FALL    0x0000040
+#define DBG_ANISOHQ 0x0000080
 /*@}*/
 
 static INLINE boolean SCREEN_DBG_ON(struct r300_screen * screen, unsigned flags)

src/gallium/drivers/r300/r300_state.c

@@ -849,6 +849,7 @@ static void*
 {
     struct r300_context* r300 = r300_context(pipe);
     struct r300_sampler_state* sampler = CALLOC_STRUCT(r300_sampler_state);
+    boolean is_r500 = r300_screen(pipe->screen)->caps->is_r500;
     int lod_bias;
     union util_color uc;
 
@@ -875,6 +876,14 @@ static void*
 
     sampler->filter1 |= lod_bias << R300_LOD_BIAS_SHIFT;
 
+    /* This is very high quality anisotropic filtering for R5xx.
+     * It's good for benchmarking the performance of texturing but
+     * in practice we don't want to slow down the driver because it's
+     * a pretty good performance killer. Feel free to play with it. */
+    if (DBG_ON(r300, DBG_ANISOHQ) && is_r500) {
+        sampler->filter1 |= r500_anisotropy(state->max_anisotropy);
+    }
+
     util_pack_color(state->border_color, PIPE_FORMAT_B8G8R8A8_UNORM, &uc);
     sampler->border_color = uc.ui;
 

src/gallium/drivers/r300/r300_state_inlines.h

@@ -327,6 +327,18 @@ static INLINE uint32_t r300_anisotropy(unsigned max_aniso)
     }
 }
 
+static INLINE uint32_t r500_anisotropy(unsigned max_aniso)
+{
+    if (!max_aniso) {
+        return 0;
+    }
+    max_aniso -= 1;
+
+    // Map the range [0, 15] to [0, 63].
+    return R500_TX_MAX_ANISO(MIN2((unsigned)(max_aniso*4.2001), 63)) |
+           R500_TX_ANISO_HIGH_QUALITY;;
+}
+
 /* Non-CSO state. (For now.) */
 
 static INLINE uint32_t r300_translate_gb_pipes(int pipe_count)