From fef8ab22e3bc8e073b63ec2cc612d91d8b81a9f6 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Tue, 21 Feb 2023 18:12:05 +0100
Subject: output: introduce wlr_output_configure_primary_swapchain()
The goal is to simplify wlr_output by moving all of its rendering
API into separate helpers. Here is a first step to sunset
wlr_output_attach_render(). Instead, compositors call
wlr_output_configure_primary_swapchain(), wlr_swapchain_acquire(),
wlr_renderer_begin_with_buffer() and wlr_output_attach_buffer().
Note that compositors can supply a base struct wlr_output_state.
This is useful to allocate a buffer suitable for submission with
a modeset, for instance.
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3079
References: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/3197
References: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/3984
---
include/wlr/types/wlr_output.h | 14 ++++++
types/meson.build | 1 +
types/output/swapchain.c | 109 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 124 insertions(+)
create mode 100644 types/output/swapchain.c
diff --git a/include/wlr/types/wlr_output.h b/include/wlr/types/wlr_output.h
index 9ea1188f..bd379444 100644
--- a/include/wlr/types/wlr_output.h
+++ b/include/wlr/types/wlr_output.h
@@ -563,6 +563,20 @@ void wlr_output_state_set_buffer(struct wlr_output_state *state,
struct wlr_buffer *buffer);
+/**
+ * Re-configure the swapchain as required for the output's primary buffer.
+ *
+ * If a NULL swapchain is passed in, a new swapchain is allocated. If the
+ * swapchain is already suitable for the output's primary buffer, this function
+ * is a no-op.
+ *
+ * The state describes the output changes the swapchain's buffers will be
+ * committed with. A NULL state indicates no change.
+ */
+bool wlr_output_configure_primary_swapchain(struct wlr_output *output,
+ const struct wlr_output_state *state, struct wlr_swapchain **swapchain);
+
+
/**
* Returns the transform that, when composed with `tr`, gives
* `WL_OUTPUT_TRANSFORM_NORMAL`.
diff --git a/types/meson.build b/types/meson.build
index eb8aa158..1e5769d7 100644
--- a/types/meson.build
+++ b/types/meson.build
@@ -7,6 +7,7 @@ wlr_files += files(
'output/output.c',
'output/render.c',
'output/state.c',
+ 'output/swapchain.c',
'output/transform.c',
'scene/drag_icon.c',
'scene/subsurface_tree.c',
diff --git a/types/output/swapchain.c b/types/output/swapchain.c
new file mode 100644
index 00000000..12018a3c
--- /dev/null
+++ b/types/output/swapchain.c
@@ -0,0 +1,109 @@
+#include <assert.h>
+#include <drm_fourcc.h>
+#include <stdlib.h>
+#include <wlr/render/allocator.h>
+#include <wlr/render/swapchain.h>
+#include <wlr/util/log.h>
+#include <xf86drm.h>
+
+#include "render/drm_format_set.h"
+#include "types/wlr_output.h"
+
+static struct wlr_swapchain *create_swapchain(struct wlr_output *output,
+ int width, int height, bool allow_modifiers) {
+ struct wlr_allocator *allocator = output->allocator;
+ assert(output->allocator != NULL);
+
+ const struct wlr_drm_format_set *display_formats =
+ wlr_output_get_primary_formats(output, allocator->buffer_caps);
+ struct wlr_drm_format *format = output_pick_format(output, display_formats,
+ output->render_format);
+ if (format == NULL) {
+ wlr_log(WLR_ERROR, "Failed to pick primary buffer format for output '%s'",
+ output->name);
+ return NULL;
+ }
+
+ char *format_name = drmGetFormatName(format->format);
+ wlr_log(WLR_DEBUG, "Choosing primary buffer format %s (0x%08"PRIX32") for output '%s'",
+ format_name ? format_name : "<unknown>", format->format, output->name);
+ free(format_name);
+
+ if (!allow_modifiers && (format->len != 1 || format->modifiers[0] != DRM_FORMAT_MOD_LINEAR)) {
+ if (!wlr_drm_format_has(format, DRM_FORMAT_MOD_INVALID)) {
+ wlr_log(WLR_DEBUG, "Implicit modifiers not supported");
+ free(format);
+ return NULL;
+ }
+
+ format->len = 0;
+ wlr_drm_format_add(&format, DRM_FORMAT_MOD_INVALID);
+ }
+
+ struct wlr_swapchain *swapchain = wlr_swapchain_create(allocator, width, height, format);
+ free(format);
+ return swapchain;
+}
+
+static bool test_swapchain(struct wlr_output *output,
+ struct wlr_swapchain *swapchain, const struct wlr_output_state *state) {
+ struct wlr_buffer *buffer = wlr_swapchain_acquire(swapchain, NULL);
+ if (buffer == NULL) {
+ return false;
+ }
+
+ struct wlr_output_state copy = *state;
+ copy.committed |= WLR_OUTPUT_STATE_BUFFER;
+ copy.buffer = buffer;
+ bool ok = wlr_output_test_state(output, ©);
+ wlr_buffer_unlock(buffer);
+ return ok;
+}
+
+bool wlr_output_configure_primary_swapchain(struct wlr_output *output,
+ const struct wlr_output_state *state, struct wlr_swapchain **swapchain_ptr) {
+ const struct wlr_output_state empty_state = {0};
+ if (state == NULL) {
+ state = &empty_state;
+ }
+
+ int width, height;
+ output_pending_resolution(output, state, &width, &height);
+
+ // Re-use the existing swapchain if possible
+ struct wlr_swapchain *old_swapchain = *swapchain_ptr;
+ if (old_swapchain != NULL &&
+ old_swapchain->width == width && old_swapchain->height == height &&
+ old_swapchain->format->format == output->render_format) {
+ return true;
+ }
+
+ struct wlr_swapchain *swapchain = create_swapchain(output, width, height, true);
+ if (swapchain == NULL) {
+ wlr_log(WLR_ERROR, "Failed to create swapchain for output '%s'", output->name);
+ return false;
+ }
+
+ wlr_log(WLR_DEBUG, "Testing swapchain for output '%s'", output->name);
+ if (!test_swapchain(output, swapchain, state)) {
+ wlr_log(WLR_DEBUG, "Output test failed on '%s', retrying without modifiers",
+ output->name);
+ wlr_swapchain_destroy(swapchain);
+ swapchain = create_swapchain(output, width, height, false);
+ if (swapchain == NULL) {
+ wlr_log(WLR_ERROR, "Failed to create modifier-less swapchain for output '%s'",
+ output->name);
+ return NULL;
+ }
+ wlr_log(WLR_DEBUG, "Testing modifier-less swapchain for output '%s'", output->name);
+ if (!test_swapchain(output, swapchain, state)) {
+ wlr_log(WLR_ERROR, "Swapchain for output '%s' failed test", output->name);
+ wlr_swapchain_destroy(swapchain);
+ return NULL;
+ }
+ }
+
+ wlr_swapchain_destroy(*swapchain_ptr);
+ *swapchain_ptr = swapchain;
+ return true;
+}
--
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