Luca,
Thanks for looking into this - this is a bit of a grey area for me.
One question - do we need a full floating point value to represent
max_anisotropy? What is the typical maximum value for max_anisotropy in
hardware, and how may levels are there? From the patch below, most
DX9-level hardware seems to support only one or two levels - is newer
hardware significantly more flexible?
I'm a bit swamped by an email backlog from christmas & are working
through your previous patches and threads. Hopefully will be caught up
soon.
Keith
On Fri, 2010-01-01 at 14:32 -0800, Luca Barbieri wrote:
> Currently Gallium defines a specific filtering mode for anisotropic filtering.
>
> This however prevents proper implementation of
> GL_EXT_texture_filter_anisotropic.
>
> The spec (written by nVidia) contains the following text:
> <<<
> A texture's maximum degree of anisotropy is specified independent
> from the texture's minification and magnification filter (as
> opposed to being supported as an entirely new filtering mode).
> Implementations are free to use the specified minification and
> magnification filter to select a particular anisotropic texture
> filtering scheme. For example, a NEAREST filter with a maximum
> degree of anisotropy of two could be treated as a 2-tap filter that
> accounts for the direction of anisotropy. Implementations are also
> permitted to ignore the minification or magnification filter and
> implement the highest quality of anisotropic filtering possible.
> >>
>
> and
>
> <<<
> Should there be a particular anisotropic texture filtering minification
> and magnification mode?
>
> RESOLUTION: NO. The maximum degree of anisotropy should control
> when anisotropic texturing is used. Making this orthogonal to
> the minification and magnification filtering modes allows these
> settings to influence the anisotropic scheme used. Yes, such
> an anisotropic filtering scheme exists in hardware.
> >>>
>
> Gallium does the opposite, and this prevents use of nearest anisotropic
> filtering which is supported in nVidia hardware and also introduces redundant
> state.
>
> This patch removes PIPE_TEX_FILTER_ANISO.
> Anisotropic filtering is enabled if and only if max_anisotropy > 1.0.
> Values between 0.0 and 1.0, inclusive, of max_anisotropy are to be considered
> equivalent, and meaning to turn off anisotropic filtering.
>
> This approach has the small drawback of eliminating the possibility of
> enabling anisotropic filter on either minification or magnification
> separately, which Radeon hardware seems to support, is currently support by
> Gallium but not exposed to OpenGL.
> If this is actually useful it could be handled by splitting max_anisotropy in
> two values and adding an appropriate OpenGL extension.
>
> How does Radeon anisotropic magnification differ from linear magnification?
> ---
> src/gallium/auxiliary/util/u_debug_dump.c | 6 +--
> src/gallium/drivers/cell/spu/spu_command.c | 4 --
> src/gallium/drivers/i915/i915_state.c | 5 +-
> src/gallium/drivers/i965/brw_pipe_sampler.c | 2 -
> src/gallium/drivers/llvmpipe/lp_bld_sample_soa.c | 1 -
> src/gallium/drivers/llvmpipe/lp_tex_sample_c.c | 3 -
> src/gallium/drivers/nv50/nv50_state.c | 2 -
> src/gallium/drivers/r300/r300_state.c | 2 +-
> src/gallium/drivers/r300/r300_state_inlines.h | 58 ++++++++++-----------
> src/gallium/drivers/svga/svga_pipe_sampler.c | 3 +-
> src/gallium/include/pipe/p_defines.h | 4 +-
> src/gallium/state_trackers/vega/image.c | 2 +-
> src/mesa/state_tracker/st_atom_sampler.c | 4 --
> 13 files changed, 40 insertions(+), 56 deletions(-)
>
> diff --git a/src/gallium/auxiliary/util/u_debug_dump.c
> b/src/gallium/auxiliary/util/u_debug_dump.c
> index 0986688..61624d0 100644
> --- a/src/gallium/auxiliary/util/u_debug_dump.c
> +++ b/src/gallium/auxiliary/util/u_debug_dump.c
> @@ -255,15 +255,13 @@ DEFINE_DEBUG_DUMP_CONTINUOUS(tex_mipfilter)
> static const char *
> debug_dump_tex_filter_names[] = {
> "PIPE_TEX_FILTER_NEAREST",
> - "PIPE_TEX_FILTER_LINEAR",
> - "PIPE_TEX_FILTER_ANISO"
> + "PIPE_TEX_FILTER_LINEAR"
> };
>
> static const char *
> debug_dump_tex_filter_short_names[] = {
> "nearest",
> - "linear",
> - "aniso"
> + "linear"
> };
>
> DEFINE_DEBUG_DUMP_CONTINUOUS(tex_filter)
> diff --git a/src/gallium/drivers/cell/spu/spu_command.c
> b/src/gallium/drivers/cell/spu/spu_command.c
> index 5c0179d..12b855a 100644
> --- a/src/gallium/drivers/cell/spu/spu_command.c
> +++ b/src/gallium/drivers/cell/spu/spu_command.c
> @@ -405,8 +405,6 @@ cmd_state_sampler(const struct cell_command_sampler
> *sampler)
> case PIPE_TEX_FILTER_LINEAR:
> spu.min_sample_texture_2d[unit] = sample_texture_2d_bilinear;
> break;
> - case PIPE_TEX_FILTER_ANISO:
> - /* fall-through, for now */
> case PIPE_TEX_FILTER_NEAREST:
> spu.min_sample_texture_2d[unit] = sample_texture_2d_nearest;
> break;
> @@ -418,8 +416,6 @@ cmd_state_sampler(const struct cell_command_sampler
> *sampler)
> case PIPE_TEX_FILTER_LINEAR:
> spu.mag_sample_texture_2d[unit] = sample_texture_2d_bilinear;
> break;
> - case PIPE_TEX_FILTER_ANISO:
> - /* fall-through, for now */
> case PIPE_TEX_FILTER_NEAREST:
> spu.mag_sample_texture_2d[unit] = sample_texture_2d_nearest;
> break;
> diff --git a/src/gallium/drivers/i915/i915_state.c
> b/src/gallium/drivers/i915/i915_state.c
> index 1528afc..5f5b6f8 100644
> --- a/src/gallium/drivers/i915/i915_state.c
> +++ b/src/gallium/drivers/i915/i915_state.c
> @@ -74,8 +74,6 @@ static unsigned translate_img_filter( unsigned filter )
> return FILTER_NEAREST;
> case PIPE_TEX_FILTER_LINEAR:
> return FILTER_LINEAR;
> - case PIPE_TEX_FILTER_ANISO:
> - return FILTER_ANISOTROPIC;
> default:
> assert(0);
> return FILTER_NEAREST;
> @@ -221,6 +219,9 @@ i915_create_sampler_state(struct pipe_context *pipe,
> minFilt = translate_img_filter( sampler->min_img_filter );
> magFilt = translate_img_filter( sampler->mag_img_filter );
>
> + if (sampler->max_anisotropy > 1.0)
> + minFilt = magFilt = FILTER_ANISOTROPIC;
> +
> if (sampler->max_anisotropy > 2.0) {
> cso->state[0] |= SS2_MAX_ANISO_4;
> }
> diff --git a/src/gallium/drivers/i965/brw_pipe_sampler.c
> b/src/gallium/drivers/i965/brw_pipe_sampler.c
> index 5ddc63f..8171279 100644
> --- a/src/gallium/drivers/i965/brw_pipe_sampler.c
> +++ b/src/gallium/drivers/i965/brw_pipe_sampler.c
> @@ -48,8 +48,6 @@ static GLuint translate_img_filter( unsigned filter )
> return BRW_MAPFILTER_NEAREST;
> case PIPE_TEX_FILTER_LINEAR:
> return BRW_MAPFILTER_LINEAR;
> - case PIPE_TEX_FILTER_ANISO:
> - return BRW_MAPFILTER_ANISOTROPIC;
> default:
> assert(0);
> return BRW_MAPFILTER_NEAREST;
> diff --git a/src/gallium/drivers/llvmpipe/lp_bld_sample_soa.c
> b/src/gallium/drivers/llvmpipe/lp_bld_sample_soa.c
> index 47b68b7..c46fef5 100644
> --- a/src/gallium/drivers/llvmpipe/lp_bld_sample_soa.c
> +++ b/src/gallium/drivers/llvmpipe/lp_bld_sample_soa.c
> @@ -577,7 +577,6 @@ lp_build_sample_soa(LLVMBuilderRef builder,
> lp_build_sample_2d_nearest_soa(&bld, s, t, width, height, stride,
> data_ptr, texel);
> break;
> case PIPE_TEX_FILTER_LINEAR:
> - case PIPE_TEX_FILTER_ANISO:
> if(lp_format_is_rgba8(bld.format_desc))
> lp_build_sample_2d_linear_aos(&bld, s, t, width, height, stride,
> data_ptr, texel);
> else
> diff --git a/src/gallium/drivers/llvmpipe/lp_tex_sample_c.c
> b/src/gallium/drivers/llvmpipe/lp_tex_sample_c.c
> index 0d01c07..91a3aed 100644
> --- a/src/gallium/drivers/llvmpipe/lp_tex_sample_c.c
> +++ b/src/gallium/drivers/llvmpipe/lp_tex_sample_c.c
> @@ -1131,7 +1131,6 @@ lp_get_samples_2d_common(struct tgsi_sampler
> *tgsi_sampler,
> }
> break;
> case PIPE_TEX_FILTER_LINEAR:
> - case PIPE_TEX_FILTER_ANISO:
> {
> int x0[4], y0[4], x1[4], y1[4];
> float xw[4], yw[4]; /* weights */
> @@ -1283,7 +1282,6 @@ lp_get_samples_3d(struct tgsi_sampler *tgsi_sampler,
> }
> break;
> case PIPE_TEX_FILTER_LINEAR:
> - case PIPE_TEX_FILTER_ANISO:
> {
> int x0[4], x1[4], y0[4], y1[4], z0[4], z1[4];
> float xw[4], yw[4], zw[4]; /* interpolation weights */
> @@ -1414,7 +1412,6 @@ lp_get_samples_rect(struct tgsi_sampler *tgsi_sampler,
> }
> break;
> case PIPE_TEX_FILTER_LINEAR:
> - case PIPE_TEX_FILTER_ANISO:
> {
> int x0[4], y0[4], x1[4], y1[4];
> float xw[4], yw[4]; /* weights */
> diff --git a/src/gallium/drivers/nv50/nv50_state.c
> b/src/gallium/drivers/nv50/nv50_state.c
> index 30b2b0f..ce4b5c8 100644
> --- a/src/gallium/drivers/nv50/nv50_state.c
> +++ b/src/gallium/drivers/nv50/nv50_state.c
> @@ -146,7 +146,6 @@ nv50_sampler_state_create(struct pipe_context *pipe,
> (wrap_mode(cso->wrap_r) << 6));
>
> switch (cso->mag_img_filter) {
> - case PIPE_TEX_FILTER_ANISO:
> case PIPE_TEX_FILTER_LINEAR:
> tsc[1] |= NV50TSC_1_1_MAGF_LINEAR;
> break;
> @@ -157,7 +156,6 @@ nv50_sampler_state_create(struct pipe_context *pipe,
> }
>
> switch (cso->min_img_filter) {
> - case PIPE_TEX_FILTER_ANISO:
> case PIPE_TEX_FILTER_LINEAR:
> tsc[1] |= NV50TSC_1_1_MINF_LINEAR;
> break;
> diff --git a/src/gallium/drivers/r300/r300_state.c
> b/src/gallium/drivers/r300/r300_state.c
> index 4907246..dcff7b7 100644
> --- a/src/gallium/drivers/r300/r300_state.c
> +++ b/src/gallium/drivers/r300/r300_state.c
> @@ -556,7 +556,7 @@ static void*
>
> sampler->filter0 |= r300_translate_tex_filters(state->min_img_filter,
> state->mag_img_filter,
> - state->min_mip_filter);
> + state->min_mip_filter,
> state->max_anisotropy > 1.0);
>
> /* Unfortunately, r300-r500 don't support floating-point mipmap lods. */
> /* We must pass these to the emit function to clamp them properly. */
> diff --git a/src/gallium/drivers/r300/r300_state_inlines.h
> b/src/gallium/drivers/r300/r300_state_inlines.h
> index dbe42ed..7852465 100644
> --- a/src/gallium/drivers/r300/r300_state_inlines.h
> +++ b/src/gallium/drivers/r300/r300_state_inlines.h
> @@ -257,38 +257,36 @@ static INLINE uint32_t r300_translate_wrap(int wrap)
> }
> }
>
> -static INLINE uint32_t r300_translate_tex_filters(int min, int mag, int mip)
> +static INLINE uint32_t r300_translate_tex_filters(int min, int mag, int mip,
> int is_anisotropic)
> {
> uint32_t retval = 0;
> - switch (min) {
> - case PIPE_TEX_FILTER_NEAREST:
> - retval |= R300_TX_MIN_FILTER_NEAREST;
> - break;
> - case PIPE_TEX_FILTER_LINEAR:
> - retval |= R300_TX_MIN_FILTER_LINEAR;
> - break;
> - case PIPE_TEX_FILTER_ANISO:
> - retval |= R300_TX_MIN_FILTER_ANISO;
> - break;
> - default:
> - debug_printf("r300: Unknown texture filter %d\n", min);
> - assert(0);
> - break;
> - }
> - switch (mag) {
> - case PIPE_TEX_FILTER_NEAREST:
> - retval |= R300_TX_MAG_FILTER_NEAREST;
> - break;
> - case PIPE_TEX_FILTER_LINEAR:
> - retval |= R300_TX_MAG_FILTER_LINEAR;
> - break;
> - case PIPE_TEX_FILTER_ANISO:
> - retval |= R300_TX_MAG_FILTER_ANISO;
> - break;
> - default:
> - debug_printf("r300: Unknown texture filter %d\n", mag);
> - assert(0);
> - break;
> + if(is_anisotropic)
> + retval |= R300_TX_MIN_FILTER_ANISO | R300_TX_MAG_FILTER_ANISO;
> + else {
> + switch (min) {
> + case PIPE_TEX_FILTER_NEAREST:
> + retval |= R300_TX_MIN_FILTER_NEAREST;
> + break;
> + case PIPE_TEX_FILTER_LINEAR:
> + retval |= R300_TX_MIN_FILTER_LINEAR;
> + break;
> + default:
> + debug_printf("r300: Unknown texture filter %d\n", min);
> + assert(0);
> + break;
> + }
> + switch (mag) {
> + case PIPE_TEX_FILTER_NEAREST:
> + retval |= R300_TX_MAG_FILTER_NEAREST;
> + break;
> + case PIPE_TEX_FILTER_LINEAR:
> + retval |= R300_TX_MAG_FILTER_LINEAR;
> + break;
> + default:
> + debug_printf("r300: Unknown texture filter %d\n", mag);
> + assert(0);
> + break;
> + }
> }
> switch (mip) {
> case PIPE_TEX_MIPFILTER_NONE:
> diff --git a/src/gallium/drivers/svga/svga_pipe_sampler.c
> b/src/gallium/drivers/svga/svga_pipe_sampler.c
> index 78053e7..460a101 100644
> --- a/src/gallium/drivers/svga/svga_pipe_sampler.c
> +++ b/src/gallium/drivers/svga/svga_pipe_sampler.c
> @@ -76,7 +76,6 @@ static INLINE unsigned translate_img_filter( unsigned
> filter )
> switch (filter) {
> case PIPE_TEX_FILTER_NEAREST: return SVGA3D_TEX_FILTER_NEAREST;
> case PIPE_TEX_FILTER_LINEAR: return SVGA3D_TEX_FILTER_LINEAR;
> - case PIPE_TEX_FILTER_ANISO: return SVGA3D_TEX_FILTER_ANISOTROPIC;
> default:
> assert(0);
> return SVGA3D_TEX_FILTER_NEAREST;
> @@ -107,6 +106,8 @@ svga_create_sampler_state(struct pipe_context *pipe,
> cso->magfilter = translate_img_filter( sampler->mag_img_filter );
> cso->minfilter = translate_img_filter( sampler->min_img_filter );
> cso->aniso_level = MAX2( (unsigned) sampler->max_anisotropy, 1 );
> + if(cso->aniso_level != 1)
> + cso->magfilter = cso->minfilter = SVGA3D_TEX_FILTER_ANISOTROPIC;
> cso->lod_bias = sampler->lod_bias;
> cso->addressu = translate_wrap_mode(sampler->wrap_s);
> cso->addressv = translate_wrap_mode(sampler->wrap_t);
> diff --git a/src/gallium/include/pipe/p_defines.h
> b/src/gallium/include/pipe/p_defines.h
> index 2cda408..a1ed2be 100644
> --- a/src/gallium/include/pipe/p_defines.h
> +++ b/src/gallium/include/pipe/p_defines.h
> @@ -171,7 +171,9 @@ enum pipe_texture_target {
> */
> #define PIPE_TEX_FILTER_NEAREST 0
> #define PIPE_TEX_FILTER_LINEAR 1
> -#define PIPE_TEX_FILTER_ANISO 2
> +
> +/* obsolete: max_anisotropy is now used to determine whether anisotropic
> filtering is enabled */
> +#define PIPE_TEX_FILTER_ANISO PIPE_TEX_FILTER_LINEAR
>
>
> #define PIPE_TEX_COMPARE_NONE 0
> diff --git a/src/gallium/state_trackers/vega/image.c
> b/src/gallium/state_trackers/vega/image.c
> index 278ba6d..1112ad9 100644
> --- a/src/gallium/state_trackers/vega/image.c
> +++ b/src/gallium/state_trackers/vega/image.c
> @@ -644,7 +644,7 @@ VGint image_sampler_filter(struct vg_context *ctx)
> return PIPE_TEX_FILTER_NEAREST;
> break;
> case VG_IMAGE_QUALITY_BETTER:
> - /*return PIPE_TEX_FILTER_ANISO;*/
> + /* possibly use anisotropic filtering */
> return PIPE_TEX_FILTER_LINEAR;
> break;
> default:
> diff --git a/src/mesa/state_tracker/st_atom_sampler.c
> b/src/mesa/state_tracker/st_atom_sampler.c
> index d6e3a3e..48ff342 100644
> --- a/src/mesa/state_tracker/st_atom_sampler.c
> +++ b/src/mesa/state_tracker/st_atom_sampler.c
> @@ -213,10 +213,6 @@ update_samplers(struct st_context *st)
> sampler->border_color);
>
> sampler->max_anisotropy = texobj->MaxAnisotropy;
> - if (sampler->max_anisotropy > 1.0) {
> - sampler->min_img_filter = PIPE_TEX_FILTER_ANISO;
> - sampler->mag_img_filter = PIPE_TEX_FILTER_ANISO;
> - }
>
> /* only care about ARB_shadow, not SGI shadow */
> if (texobj->CompareMode == GL_COMPARE_R_TO_TEXTURE) {
> --
> 1.6.3.3
>
>
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