asahi: Add data structures for geometry shaders

Shared between GPU and CPU.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26056>

src/asahi/lib/shaders/geometry.h

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2023 Alyssa Rosenzweig
+ * Copyright 2023 Valve Corporation
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "compiler/shader_enums.h"
+#include "libagx.h"
+
+#ifndef __OPENCL_VERSION__
+#include "util/macros.h"
+#define GLOBAL(type_) uint64_t
+#else
+#define PACKED
+#define GLOBAL(type_) global type_ *
+#endif
+
+#ifndef LIBAGX_GEOMETRY_H
+#define LIBAGX_GEOMETRY_H
+
+#define MAX_SO_BUFFERS     4
+#define MAX_VERTEX_STREAMS 4
+
+struct agx_ia_key {
+   /* The index size (1, 2, 4) or 0 if drawing without an index buffer. */
+   uint8_t index_size;
+
+   /* The primitive mode for unrolling the vertex ID */
+   enum mesa_prim mode;
+
+   /* Use first vertex as the provoking vertex for flat shading */
+   bool flatshade_first;
+};
+
+/* Packed geometry state buffer */
+struct agx_geometry_state {
+   /* Heap to allocate from, in either direction. By convention, the top is used
+    * for intra-draw allocations and the bottom is used for full-batch
+    * allocations. In the future we could use kernel support to improve this.
+    */
+   GLOBAL(uchar) heap;
+   uint32_t heap_bottom, heap_top, heap_size, padding;
+} PACKED;
+
+struct agx_geometry_params {
+   /* Persistent (cross-draw) geometry state */
+   GLOBAL(struct agx_geometry_state) state;
+
+   /* Address of associated indirect draw buffer */
+   GLOBAL(uint) indirect_desc;
+
+   /* Address of count buffer. For an indirect draw, this will be written by the
+    * indirect setup kernel.
+    */
+   GLOBAL(uint) count_buffer;
+
+   /* Address of the primitives generated counters */
+   GLOBAL(uint) prims_generated_counter[MAX_VERTEX_STREAMS];
+   GLOBAL(uint) xfb_prims_generated_counter[MAX_VERTEX_STREAMS];
+
+   /* Pointers to transform feedback buffer offsets in bytes */
+   GLOBAL(uint) xfb_offs_ptrs[MAX_SO_BUFFERS];
+
+   /* Output (vertex) buffer, allocated by pre-GS. */
+   GLOBAL(uint) output_buffer;
+
+   /* Output index buffer, allocated by pre-GS. */
+   GLOBAL(uint) output_index_buffer;
+
+   /* Address of transform feedback buffer in general, supplied by the CPU. */
+   GLOBAL(uchar) xfb_base_original[MAX_SO_BUFFERS];
+   uint32_t xfb_size[MAX_SO_BUFFERS];
+
+   /* Address of transform feedback for the current primitive. Written by pre-GS
+    * program.
+    */
+   GLOBAL(uchar) xfb_base[MAX_SO_BUFFERS];
+
+   /* Number of primitives emitted by transform feedback per stream. Written by
+    * the pre-GS program.
+    */
+   uint32_t xfb_prims[MAX_VERTEX_STREAMS];
+
+   /* Address of input index buffer for an indexed draw (this includes
+    * tessellation - it's the index buffer coming into the geometry stage).
+    */
+   GLOBAL(uchar) input_index_buffer;
+
+   /* Address of input indirect buffer for indirect GS draw */
+   GLOBAL(uint) input_indirect_desc;
+
+   /* Within an indirect GS draw, the grid used to dispatch the GS written out
+    * by the GS indirect setup kernel. Unused for direct GS draws.
+    */
+   uint32_t gs_grid[3];
+
+   /* Number of input primitives, calculated by the CPU for a direct draw or the
+    * GS indirect setup kernel for an indirect draw.
+    */
+   uint32_t input_primitives;
+
+   /* Number of bytes output by the GS count shader per input primitive (may be
+    * 0), written by CPU and consumed by indirect draw setup shader for
+    * allocating counts.
+    */
+   uint32_t count_buffer_stride;
+
+   /* Size of a single input index in bytes, or 0 if indexing is disabled.
+    *
+    *    index_size_B == 0 <==> input_index_buffer == NULL
+    */
+   uint32_t index_size_B;
+} PACKED;
+
+#endif