From b4765809b5e7da43a850d455c98a468992843db9 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Fri, 23 Sep 2022 21:55:29 +0200
Subject: [PATCH] render: add wlr_renderer_get_time()

This queries the current GPU time.

[1]: https://registry.khronos.org/OpenGL/extensions/EXT/EXT_disjoint_timer_query.txt

References: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3025
---
 include/render/gles2.h            |  6 ++++++
 include/wlr/render/interface.h    |  1 +
 include/wlr/render/wlr_renderer.h |  7 +++++++
 render/gles2/renderer.c           | 24 ++++++++++++++++++++++++
 render/wlr_renderer.c             |  7 +++++++
 5 files changed, 45 insertions(+)

diff --git a/include/render/gles2.h b/include/render/gles2.h
index 714bacf56..5ce9c6771 100644
--- a/include/render/gles2.h
+++ b/include/render/gles2.h
@@ -32,6 +32,10 @@ struct wlr_gles2_tex_shader {
 	GLint tex_attrib;
 };
 
+// Fixed here, but missing from any libglvnd release:
+// https://gitlab.freedesktop.org/glvnd/libglvnd/-/merge_requests/268
+typedef void (GL_APIENTRYP PFNGLGETINTEGER64VEXTPROC) (GLenum pname, GLint64 *data);
+
 struct wlr_gles2_renderer {
 	struct wlr_renderer wlr_renderer;
 
@@ -48,6 +52,7 @@ struct wlr_gles2_renderer {
 		bool EXT_texture_type_2_10_10_10_REV;
 		bool OES_texture_half_float_linear;
 		bool EXT_texture_norm16;
+		bool EXT_disjoint_timer_query;
 	} exts;
 
 	struct {
@@ -57,6 +62,7 @@ struct wlr_gles2_renderer {
 		PFNGLPOPDEBUGGROUPKHRPROC glPopDebugGroupKHR;
 		PFNGLPUSHDEBUGGROUPKHRPROC glPushDebugGroupKHR;
 		PFNGLEGLIMAGETARGETRENDERBUFFERSTORAGEOESPROC glEGLImageTargetRenderbufferStorageOES;
+		PFNGLGETINTEGER64VEXTPROC glGetInteger64vEXT;
 	} procs;
 
 	struct {
diff --git a/include/wlr/render/interface.h b/include/wlr/render/interface.h
index e347f29be..a9828827e 100644
--- a/include/wlr/render/interface.h
+++ b/include/wlr/render/interface.h
@@ -48,6 +48,7 @@ struct wlr_renderer_impl {
 	uint32_t (*get_render_buffer_caps)(struct wlr_renderer *renderer);
 	struct wlr_texture *(*texture_from_buffer)(struct wlr_renderer *renderer,
 		struct wlr_buffer *buffer);
+	bool (*get_time)(struct wlr_renderer *r, struct timespec *t);
 };
 
 void wlr_renderer_init(struct wlr_renderer *renderer,
diff --git a/include/wlr/render/wlr_renderer.h b/include/wlr/render/wlr_renderer.h
index e240897d4..70aeb6cdf 100644
--- a/include/wlr/render/wlr_renderer.h
+++ b/include/wlr/render/wlr_renderer.h
@@ -14,6 +14,8 @@
 #include <wlr/backend.h>
 #include <wlr/render/wlr_texture.h>
 
+struct timespec;
+
 struct wlr_renderer_impl;
 struct wlr_drm_format_set;
 struct wlr_buffer;
@@ -112,6 +114,11 @@ bool wlr_renderer_init_wl_shm(struct wlr_renderer *r,
  */
 int wlr_renderer_get_drm_fd(struct wlr_renderer *r);
 
+/**
+ * Get the current GPU time.
+ */
+bool wlr_renderer_get_time(struct wlr_renderer *r, struct timespec *t);
+
 /**
  * Destroys the renderer.
  *
diff --git a/render/gles2/renderer.c b/render/gles2/renderer.c
index b1543cddc..4a8e42e16 100644
--- a/render/gles2/renderer.c
+++ b/render/gles2/renderer.c
@@ -18,6 +18,7 @@
 #include "render/gles2.h"
 #include "render/pixel_format.h"
 #include "types/wlr_matrix.h"
+#include "util/time.h"
 
 static const GLfloat verts[] = {
 	1, 0, // top right
@@ -485,6 +486,23 @@ struct wlr_egl *wlr_gles2_renderer_get_egl(struct wlr_renderer *wlr_renderer) {
 	return renderer->egl;
 }
 
+static bool gles2_get_time(struct wlr_renderer *wlr_renderer, struct timespec *t) {
+	struct wlr_gles2_renderer *renderer =
+		gles2_get_renderer_in_context(wlr_renderer);
+
+	if (!renderer->exts.EXT_disjoint_timer_query) {
+		return false;
+	}
+
+	GLint64 nsec = 0;
+	push_gles2_debug(renderer);
+	renderer->procs.glGetInteger64vEXT(GL_TIMESTAMP_EXT, &nsec);
+	pop_gles2_debug(renderer);
+
+	timespec_from_nsec(t, nsec);
+	return true;
+}
+
 static void gles2_destroy(struct wlr_renderer *wlr_renderer) {
 	struct wlr_gles2_renderer *renderer = gles2_get_renderer(wlr_renderer);
 
@@ -539,6 +557,7 @@ static const struct wlr_renderer_impl renderer_impl = {
 	.get_drm_fd = gles2_get_drm_fd,
 	.get_render_buffer_caps = gles2_get_render_buffer_caps,
 	.texture_from_buffer = gles2_texture_from_buffer,
+	.get_time = gles2_get_time,
 };
 
 void push_gles2_debug_(struct wlr_gles2_renderer *renderer,
@@ -768,6 +787,11 @@ struct wlr_renderer *wlr_gles2_renderer_create(struct wlr_egl *egl) {
 			"glEGLImageTargetRenderbufferStorageOES");
 	}
 
+	if (check_gl_ext(exts_str, "GL_EXT_disjoint_timer_query")) {
+		renderer->exts.EXT_disjoint_timer_query = true;
+		load_gl_proc(&renderer->procs.glGetInteger64vEXT, "glGetInteger64vEXT");
+	}
+
 	if (renderer->exts.KHR_debug) {
 		glEnable(GL_DEBUG_OUTPUT_KHR);
 		glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS_KHR);
diff --git a/render/wlr_renderer.c b/render/wlr_renderer.c
index 2d6481f00..669d2e86e 100644
--- a/render/wlr_renderer.c
+++ b/render/wlr_renderer.c
@@ -433,3 +433,10 @@ int wlr_renderer_get_drm_fd(struct wlr_renderer *r) {
 	}
 	return r->impl->get_drm_fd(r);
 }
+
+bool wlr_renderer_get_time(struct wlr_renderer *r, struct timespec *t) {
+	if (!r->impl->get_time) {
+		return false;
+	}
+	return r->impl->get_time(r, t);
+}