etnaviv: make use of nir_lower_tex_shadow

Also force the texture filter to nearest when the lowering
is used.

This enables the GL_ARB_shadow extension for all GPU models.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14308>

src/gallium/drivers/etnaviv/etnaviv_compiler_nir.c

@@ -1118,6 +1118,12 @@ etna_compile_shader_nir(struct etna_shader_variant *v)
    NIR_PASS_V(s, nir_lower_vars_to_ssa);
    NIR_PASS_V(s, nir_lower_indirect_derefs, nir_var_all, UINT32_MAX);
    NIR_PASS_V(s, nir_lower_tex, &(struct nir_lower_tex_options) { .lower_txp = ~0u });
+
+   if (v->key.has_sample_tex_compare)
+      NIR_PASS_V(s, nir_lower_tex_shadow, v->key.num_texture_states,
+                                          v->key.tex_compare_func,
+                                          v->key.tex_swizzle);
+
    NIR_PASS_V(s, nir_lower_alu_to_scalar, etna_alu_to_scalar_filter_cb, specs);
    nir_lower_idiv_options idiv_options = {
       .imprecise_32bit_lowering = true,

src/gallium/drivers/etnaviv/etnaviv_context.c

@@ -212,6 +212,26 @@ etna_get_fs(struct etna_context *ctx, struct etna_shader_key key)
 {
    const struct etna_shader_variant *old = ctx->shader.fs;
 
+   /* update the key if we need to run nir_lower_sample_tex_compare(..). */
+   if (ctx->screen->specs.halti < 2 &&
+       (ctx->dirty & (ETNA_DIRTY_SAMPLERS | ETNA_DIRTY_SAMPLER_VIEWS))) {
+
+      for (unsigned int i = 0; i < ctx->num_fragment_sampler_views; i++) {
+         if (ctx->sampler[i]->compare_mode == PIPE_TEX_COMPARE_NONE)
+            continue;
+
+         key.has_sample_tex_compare = 1;
+         key.num_texture_states = ctx->num_fragment_sampler_views;
+
+         key.tex_swizzle[i].swizzle_r = ctx->sampler_view[i]->swizzle_r;
+         key.tex_swizzle[i].swizzle_g = ctx->sampler_view[i]->swizzle_g;
+         key.tex_swizzle[i].swizzle_b = ctx->sampler_view[i]->swizzle_b;
+         key.tex_swizzle[i].swizzle_a = ctx->sampler_view[i]->swizzle_a;
+
+         key.tex_compare_func[i] = ctx->sampler[i]->compare_func;
+      }
+   }
+
    ctx->shader.fs = etna_shader_variant(ctx->shader.bind_fs, key, &ctx->debug);
 
    if (!ctx->shader.fs)

src/gallium/drivers/etnaviv/etnaviv_screen.c

@@ -212,7 +212,7 @@ etna_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 
    /* Texturing. */
    case PIPE_CAP_TEXTURE_SHADOW_MAP:
-      return !DBG_ENABLED(ETNA_DBG_TGSI) && screen->specs.halti >= 2;
+      return !DBG_ENABLED(ETNA_DBG_TGSI);
    case PIPE_CAP_MAX_TEXTURE_2D_SIZE:
    case PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS: /* TODO: verify */
       return screen->specs.max_texture_size;

src/gallium/drivers/etnaviv/etnaviv_shader.h

@@ -28,6 +28,7 @@
 #define H_ETNAVIV_SHADER
 
 #include "mesa/main/config.h"
+#include "nir.h"
 #include "pipe/p_state.h"
 #include "util/disk_cache.h"
 
@@ -50,17 +51,25 @@ struct etna_shader_key
          /* do we need to replace glTexCoord.xy ? */
          unsigned sprite_coord_enable : MAX_TEXTURE_COORD_UNITS;
          unsigned sprite_coord_yinvert : 1;
+         /* do we need to lower sample_tex_compare */
+         unsigned has_sample_tex_compare : 1;
       };
       uint32_t global;
    };
+
+   int num_texture_states;
+   nir_lower_tex_shadow_swizzle tex_swizzle[PIPE_MAX_SHADER_SAMPLER_VIEWS];
+   enum compare_func tex_compare_func[PIPE_MAX_SHADER_SAMPLER_VIEWS];
 };
 
 static inline bool
 etna_shader_key_equal(struct etna_shader_key *a, struct etna_shader_key *b)
 {
-   STATIC_ASSERT(sizeof(struct etna_shader_key) <= sizeof(a->global));
-
-   return a->global == b->global;
+   /* slow-path if we need to check tex_{swizzle,compare_func} */
+   if (unlikely(a->has_sample_tex_compare || b->has_sample_tex_compare))
+      return memcmp(a, b, sizeof(struct etna_shader_key)) == 0;
+   else
+      return a->global == b->global;
 }
 
 struct etna_shader {

src/gallium/drivers/etnaviv/etnaviv_texture_state.c

@@ -139,6 +139,16 @@ etna_create_sampler_state_state(struct pipe_context *pipe,
       COND(ss->compare_mode, VIVS_NTE_SAMPLER_BASELOD_COMPARE_ENABLE) |
       VIVS_NTE_SAMPLER_BASELOD_COMPARE_FUNC(translate_texture_compare(ss->compare_func));
 
+   /* force nearest filting for nir_lower_sample_tex_compare(..) */
+   if ((ctx->screen->specs.halti < 2) && ss->compare_mode) {
+      cs->config0 &= ~VIVS_TE_SAMPLER_CONFIG0_MIN__MASK;
+      cs->config0 &= ~VIVS_TE_SAMPLER_CONFIG0_MAG__MASK;
+
+      cs->config0 |=
+         VIVS_TE_SAMPLER_CONFIG0_MIN(TEXTURE_FILTER_NEAREST) |
+         VIVS_TE_SAMPLER_CONFIG0_MAG(TEXTURE_FILTER_NEAREST);
+   }
+
    return cs;
 }
 

src/gallium/drivers/etnaviv/meson.build

@@ -123,7 +123,7 @@ etnaviv_compiler = executable(
   link_with : [libgallium, libetnaviv, libetnaviv_drm],
   build_by_default : with_tools.contains('etnaviv'),
   install : with_tools.contains('etnaviv'),
-  dependencies : [idep_mesautil, dep_libdrm],
+  dependencies : [idep_mesautil, dep_libdrm, idep_nir],
 )
 
 driver_etnaviv = declare_dependency(