zink: add driver-workaround for missing gl_point_size

Add code to support gl_point lowering.

In this commit the target of this lowering will be only the
imagination proprietary driver.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20109>

src/gallium/drivers/zink/zink_compiler.c

@@ -2551,6 +2551,10 @@ zink_shader_compile(struct zink_screen *screen, struct zink_shader *zs, nir_shad
                NIR_PASS_V(nir, nir_lower_var_copies);
                need_optimize = true;
             }
+            if (zink_gs_key(key)->lower_gl_point) {
+               NIR_PASS_V(nir, lower_gl_point_gs);
+               need_optimize = true;
+            }
             break;
 
          default:

src/gallium/drivers/zink/zink_draw.cpp

@@ -800,8 +800,9 @@ zink_draw(struct pipe_context *pctx,
                          offsetof(struct zink_gfx_push_constant, default_inner_level), sizeof(float) * 6,
                          &ctx->tess_levels[0]);
    }
-   if (zink_get_fs_key(ctx)->lower_line_stipple) {
+   if (zink_get_fs_key(ctx)->lower_line_stipple ||
-      assert(zink_get_gs_key(ctx)->lower_line_stipple);
+       zink_get_gs_key(ctx)->lower_gl_point) {
+      assert(zink_get_fs_key(ctx)->lower_line_stipple == zink_get_gs_key(ctx)->lower_line_stipple);
 
       float viewport_scale[2] = {
          ctx->vp_state.viewport_states[0].scale[0],

src/gallium/drivers/zink/zink_program.c

@@ -1851,7 +1851,7 @@ zink_set_primitive_emulation_keys(struct zink_context *ctx)
       zink_set_gs_key(ctx)->lower_line_stipple = lower_line_stipple;
    }
 
-   if (lower_line_stipple) {
+   if (lower_line_stipple || zink_get_gs_key(ctx)->lower_gl_point) {
       enum pipe_shader_type prev_vertex_stage =
          ctx->gfx_stages[MESA_SHADER_TESS_EVAL] ?
             MESA_SHADER_TESS_EVAL : MESA_SHADER_VERTEX;
@@ -1863,7 +1863,9 @@ zink_set_primitive_emulation_keys(struct zink_context *ctx)
             nir_shader *nir = nir_create_passthrough_gs(
                &screen->nir_options,
                ctx->gfx_stages[prev_vertex_stage]->nir,
-               SHADER_PRIM_LINE_STRIP, 2);
+               lower_line_stipple ? SHADER_PRIM_LINE_STRIP :  SHADER_PRIM_POINTS,
+               lower_line_stipple ? 2 : 1);
+            NIR_PASS_V(nir, nir_lower_gs_intrinsics, nir_lower_gs_intrinsics_per_stream);
 
             struct zink_shader *shader = zink_shader_create(screen, nir, NULL);
             ctx->gfx_stages[prev_vertex_stage]->non_fs.generated_gs = shader;

src/gallium/drivers/zink/zink_screen.c

@@ -2349,6 +2349,19 @@ init_driver_workarounds(struct zink_screen *screen)
       screen->driver_workarounds.no_linestipple = true;
    }
 
+   /* This is a workarround for the lack of
+    * gl_PointSize + glPolygonMode(..., GL_LINE), in the imagination
+    * proprietary driver.
+    */
+   switch (screen->info.driver_props.driverID) {
+   case VK_DRIVER_ID_IMAGINATION_PROPRIETARY:
+      screen->driver_workarounds.no_hw_gl_point = true;
+      break;
+   default:
+      screen->driver_workarounds.no_hw_gl_point = false;
+      break;
+   }
+
    if (screen->info.driver_props.driverID == VK_DRIVER_ID_AMD_OPEN_SOURCE || 
        screen->info.driver_props.driverID == VK_DRIVER_ID_AMD_PROPRIETARY || 
        screen->info.driver_props.driverID == VK_DRIVER_ID_NVIDIA_PROPRIETARY || 
@@ -2717,7 +2730,8 @@ zink_internal_create_screen(const struct pipe_screen_config *config)
    screen->optimal_keys = !screen->need_decompose_attrs &&
                           screen->info.have_EXT_non_seamless_cube_map &&
                           !screen->driconf.inline_uniforms &&
-                          !screen->driver_workarounds.no_linestipple;
+                          !screen->driver_workarounds.no_linestipple &&
+                          !screen->driver_workarounds.no_hw_gl_point;
    if (!screen->optimal_keys)
       screen->info.have_EXT_graphics_pipeline_library = false;
 

src/gallium/drivers/zink/zink_shader_keys.h

@@ -60,6 +60,7 @@ struct zink_gs_key {
    struct zink_vs_key_base base;
    uint8_t pad;
    bool lower_line_stipple : 1;
+   bool lower_gl_point : 1;
    // not hashed
    unsigned size;
 };

src/gallium/drivers/zink/zink_state.c

@@ -601,8 +601,15 @@ zink_create_rasterizer_state(struct pipe_context *pctx,
    assert(rs_state->fill_front <= PIPE_POLYGON_MODE_POINT);
    if (rs_state->fill_back != rs_state->fill_front)
       debug_printf("BUG: vulkan doesn't support different front and back fill modes\n");
-   state->hw_state.polygon_mode = rs_state->fill_front; // same values
+
-   state->cull_mode = rs_state->cull_face; // same bits
+   if (rs_state->fill_front == PIPE_POLYGON_MODE_POINT &&
+       screen->driver_workarounds.no_hw_gl_point) {
+      state->hw_state.polygon_mode = VK_POLYGON_MODE_FILL;
+      state->cull_mode = VK_CULL_MODE_NONE;
+   } else {
+      state->hw_state.polygon_mode = rs_state->fill_front; // same values
+      state->cull_mode = rs_state->cull_face; // same bits
+   }
 
    state->front_face = rs_state->front_ccw ?
                        VK_FRONT_FACE_COUNTER_CLOCKWISE :
@@ -670,6 +677,11 @@ zink_bind_rasterizer_state(struct pipe_context *pctx, void *cso)
          ctx->vp_state_changed = true;
       }
 
+      bool lower_gl_point = screen->driver_workarounds.no_hw_gl_point;
+      lower_gl_point &= ctx->rast_state->base.fill_front == PIPE_POLYGON_MODE_POINT;
+      if (zink_get_gs_key(ctx)->lower_gl_point != lower_gl_point)
+         zink_set_gs_key(ctx)->lower_gl_point = lower_gl_point;
+
       if (ctx->gfx_pipeline_state.dyn_state1.front_face != ctx->rast_state->front_face) {
          ctx->gfx_pipeline_state.dyn_state1.front_face = ctx->rast_state->front_face;
          ctx->gfx_pipeline_state.dirty |= !zink_screen(pctx->screen)->info.have_EXT_extended_dynamic_state;

src/gallium/drivers/zink/zink_types.h

@@ -1282,6 +1282,7 @@ struct zink_screen {
       bool needs_sanitised_layer;
       bool track_renderpasses;
       bool no_linestipple;
+      bool no_hw_gl_point;
       unsigned z16_unscaled_bias;
       unsigned z24_unscaled_bias;
    } driver_workarounds;