render: introduce wlr_swapchain

The swapchain maximum capacity is set to 4, so that we have enough room
for:

- A buffer currently displayed on screen
- A buffer queued for display (e.g. to KMS)
- A pending buffer that'll be queued next commit
- An additional pending buffer in case we want to invalidate the
  currently pending one
This commit is contained in:
Simon Ser 2020-06-01 19:49:32 +02:00
parent 7c6212a0f7
commit b0a663d39d
3 changed files with 150 additions and 0 deletions

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@ -0,0 +1,41 @@
#ifndef RENDER_SWAPCHAIN_H
#define RENDER_SWAPCHAIN_H
#include <stdbool.h>
#include <wayland-server-core.h>
#include <wlr/render/drm_format_set.h>
#define WLR_SWAPCHAIN_CAP 4
struct wlr_swapchain_slot {
struct wlr_buffer *buffer;
bool acquired; // waiting for release
struct wl_listener release;
};
struct wlr_swapchain {
struct wlr_allocator *allocator; // NULL if destroyed
int width, height;
struct wlr_drm_format *format;
struct wlr_swapchain_slot slots[WLR_SWAPCHAIN_CAP];
struct wl_listener allocator_destroy;
};
struct wlr_swapchain *wlr_swapchain_create(
struct wlr_allocator *alloc, int width, int height,
const struct wlr_drm_format *format);
void wlr_swapchain_destroy(struct wlr_swapchain *swapchain);
/**
* Acquire a buffer from the swap chain.
*
* The returned buffer is locked. When the caller is done with it, they must
* unlock it by calling wlr_buffer_unlock.
*/
struct wlr_buffer *wlr_swapchain_acquire(
struct wlr_swapchain *swapchain);
#endif

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@ -8,6 +8,7 @@ wlr_files += files(
'gles2/renderer.c',
'gles2/shaders.c',
'gles2/texture.c',
'swapchain.c',
'wlr_renderer.c',
'wlr_texture.c',
)

108
render/swapchain.c Normal file
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@ -0,0 +1,108 @@
#include <assert.h>
#include <stdlib.h>
#include <wlr/util/log.h>
#include <wlr/types/wlr_buffer.h>
#include "render/allocator.h"
#include "render/drm_format_set.h"
#include "render/swapchain.h"
static void swapchain_handle_allocator_destroy(struct wl_listener *listener,
void *data) {
struct wlr_swapchain *swapchain =
wl_container_of(listener, swapchain, allocator_destroy);
swapchain->allocator = NULL;
}
struct wlr_swapchain *wlr_swapchain_create(
struct wlr_allocator *alloc, int width, int height,
const struct wlr_drm_format *format) {
struct wlr_swapchain *swapchain = calloc(1, sizeof(*swapchain));
if (swapchain == NULL) {
return NULL;
}
swapchain->allocator = alloc;
swapchain->width = width;
swapchain->height = height;
swapchain->format = wlr_drm_format_dup(format);
if (swapchain->format == NULL) {
free(swapchain);
return NULL;
}
swapchain->allocator_destroy.notify = swapchain_handle_allocator_destroy;
wl_signal_add(&alloc->events.destroy, &swapchain->allocator_destroy);
return swapchain;
}
static void slot_reset(struct wlr_swapchain_slot *slot) {
if (slot->acquired) {
wl_list_remove(&slot->release.link);
}
wlr_buffer_drop(slot->buffer);
memset(slot, 0, sizeof(*slot));
}
void wlr_swapchain_destroy(struct wlr_swapchain *swapchain) {
if (swapchain == NULL) {
return;
}
for (size_t i = 0; i < WLR_SWAPCHAIN_CAP; i++) {
slot_reset(&swapchain->slots[i]);
}
wl_list_remove(&swapchain->allocator_destroy.link);
free(swapchain->format);
free(swapchain);
}
static void slot_handle_release(struct wl_listener *listener, void *data) {
struct wlr_swapchain_slot *slot =
wl_container_of(listener, slot, release);
wl_list_remove(&slot->release.link);
slot->acquired = false;
}
static struct wlr_buffer *slot_acquire(struct wlr_swapchain_slot *slot) {
assert(!slot->acquired);
assert(slot->buffer != NULL);
slot->acquired = true;
slot->release.notify = slot_handle_release;
wl_signal_add(&slot->buffer->events.release, &slot->release);
return wlr_buffer_lock(slot->buffer);
}
struct wlr_buffer *wlr_swapchain_acquire(
struct wlr_swapchain *swapchain) {
struct wlr_swapchain_slot *free_slot = NULL;
for (size_t i = 0; i < WLR_SWAPCHAIN_CAP; i++) {
struct wlr_swapchain_slot *slot = &swapchain->slots[i];
if (slot->acquired) {
continue;
}
if (slot->buffer != NULL) {
return slot_acquire(slot);
}
free_slot = slot;
}
if (free_slot == NULL) {
wlr_log(WLR_ERROR, "No free output buffer slot");
return NULL;
}
if (swapchain->allocator == NULL) {
return NULL;
}
wlr_log(WLR_DEBUG, "Allocating new swapchain buffer");
free_slot->buffer = wlr_allocator_create_buffer(swapchain->allocator,
swapchain->width, swapchain->height, swapchain->format);
if (free_slot->buffer == NULL) {
wlr_log(WLR_ERROR, "Failed to allocate buffer");
return NULL;
}
return slot_acquire(free_slot);
}