zink: Blit using one triangle for nearest filtering

Fixes dEQP-GLES3.functional.fbo.blit.rect.nearest_consistency_out_of_bounds_.* on RADV.

Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28892>

src/gallium/drivers/zink/zink_blit.c

@@ -442,6 +442,8 @@ zink_blit(struct pipe_context *pctx,
       zink_resource_object_init_mutable(ctx, dst);
    zink_blit_barriers(ctx, use_src, dst, whole);
    ctx->blitting = true;
+   ctx->blit_scissor = info->scissor_enable;
+   ctx->blit_nearest = info->filter == PIPE_TEX_FILTER_NEAREST;
 
    if (stencil_blit) {
       struct pipe_surface *dst_view, dst_templ;
@@ -636,3 +638,36 @@ zink_blit_region_covers(struct u_rect region, struct u_rect covers)
     return intersect.x0 == c.x0 && intersect.y0 == c.y0 &&
            intersect.x1 == c.x1 && intersect.y1 == c.y1;
 }
+
+void
+zink_draw_rectangle(struct blitter_context *blitter, void *vertex_elements_cso,
+                    blitter_get_vs_func get_vs, int x1, int y1, int x2, int y2,
+                    float depth, unsigned num_instances, enum blitter_attrib_type type,
+                    const union blitter_attrib *attrib)
+{
+   struct zink_context *ctx = zink_context(blitter->pipe);
+
+   union blitter_attrib new_attrib = *attrib;
+
+   /* Avoid inconsistencies in rounding between both triangles which can show with
+    * nearest filtering by expanding the rect so only one triangle is effectively drawn.
+    */
+   if (ctx->blit_scissor && ctx->blit_nearest) {
+      int64_t new_x1 = (int64_t)x1 * 2 - x2;
+      int64_t new_y2 = (int64_t)y2 * 2 - y1;
+      if (new_x1 < INT32_MAX && new_x1 > INT32_MIN &&
+          new_y2 < INT32_MAX && new_y2 > INT32_MIN) {
+         x1 = new_x1;
+         y2 = new_y2;
+
+         if (type == UTIL_BLITTER_ATTRIB_TEXCOORD_XY ||
+             type == UTIL_BLITTER_ATTRIB_TEXCOORD_XYZW) {
+            new_attrib.texcoord.x1 += new_attrib.texcoord.x1 - new_attrib.texcoord.x2;
+            new_attrib.texcoord.y2 += new_attrib.texcoord.y2 - new_attrib.texcoord.y1;
+         }
+      }
+   }
+
+   util_blitter_draw_rectangle(blitter, vertex_elements_cso, get_vs, x1, y1, x2, y2,
+                               depth, num_instances, type, &new_attrib);
+}

src/gallium/drivers/zink/zink_context.c

@@ -5212,6 +5212,8 @@ zink_context_create(struct pipe_screen *pscreen, void *priv, unsigned flags)
       ctx->blitter = util_blitter_create(&ctx->base);
       if (!ctx->blitter)
          goto fail;
+      if (screen->driver_workarounds.inconsistent_interpolation)
+         ctx->blitter->draw_rectangle = zink_draw_rectangle;
    }
 
    zink_set_last_vertex_key(ctx)->last_vertex_stage = true;

src/gallium/drivers/zink/zink_context.h

@@ -232,6 +232,12 @@ zink_blit_region_fills(struct u_rect region, unsigned width, unsigned height);
 bool
 zink_blit_region_covers(struct u_rect region, struct u_rect covers);
 
+void
+zink_draw_rectangle(struct blitter_context *blitter, void *vertex_elements_cso,
+                    blitter_get_vs_func get_vs, int x1, int y1, int x2, int y2,
+                    float depth, unsigned num_instances, enum blitter_attrib_type type,
+                    const union blitter_attrib *attrib);
+
 static inline struct u_rect
 zink_rect_from_box(const struct pipe_box *box)
 {

src/gallium/drivers/zink/zink_screen.c

@@ -3052,6 +3052,8 @@ init_driver_workarounds(struct zink_screen *screen)
    case VK_DRIVER_ID_AMD_PROPRIETARY:
       /* this has bad perf on AMD */
       screen->info.have_KHR_push_descriptor = false;
+      /* Interpolation is not consistent between two triangles of a rectangle. */
+      screen->driver_workarounds.inconsistent_interpolation = true;
       break;
    default:
       break;

src/gallium/drivers/zink/zink_types.h

@@ -46,6 +46,7 @@
 #include "util/set.h"
 #include "util/simple_mtx.h"
 #include "util/slab.h"
+#include "util/u_blitter.h"
 #include "util/u_dynarray.h"
 #include "util/u_idalloc.h"
 #include "util/u_live_shader_cache.h"
@@ -1542,6 +1543,7 @@ struct zink_screen {
       bool needs_zs_shader_swizzle;
       bool can_do_invalid_linear_modifier;
       bool io_opt;
+      bool inconsistent_interpolation;
       unsigned z16_unscaled_bias;
       unsigned z24_unscaled_bias;
    } driver_workarounds;
@@ -2009,6 +2011,8 @@ struct zink_context {
    bool is_device_lost;
    bool primitive_restart;
    bool blitting : 1;
+   bool blit_scissor : 1;
+   bool blit_nearest : 1;
    bool unordered_blitting : 1;
    bool vertex_state_changed : 1;
    bool blend_state_changed : 1;