render/gles2: save/restore context when creating/submitting a render pass

This is useful for e.g. lazily blitting a texture for readback
purposes while rendering.

2 files changed, 7 insertions, 2 deletions

diff --git a/render/gles2/pass.c b/render/gles2/pass.c
index f8a0f3e8..4c9f9e28 100644
--- a/render/gles2/pass.c
+++ b/render/gles2/pass.c
@@ -41,6 +41,7 @@ static bool render_pass_submit(struct wlr_render_pass *wlr_pass) {
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
 	pop_gles2_debug(renderer);
+	wlr_egl_restore_context(&pass->prev_ctx);
 
 	wlr_buffer_unlock(pass->buffer->buffer);
 	free(pass);
@@ -247,7 +248,7 @@ static const char *reset_status_str(GLenum status) {
 }
 
 struct wlr_gles2_render_pass *begin_gles2_buffer_pass(struct wlr_gles2_buffer *buffer,
-		struct wlr_gles2_render_timer *timer) {
+		struct wlr_egl_context *prev_ctx, struct wlr_gles2_render_timer *timer) {
 	struct wlr_gles2_renderer *renderer = buffer->renderer;
 	struct wlr_buffer *wlr_buffer = buffer->buffer;
 
@@ -274,6 +275,7 @@ struct wlr_gles2_render_pass *begin_gles2_buffer_pass(struct wlr_gles2_buffer *b
 	wlr_buffer_lock(wlr_buffer);
 	pass->buffer = buffer;
 	pass->timer = timer;
+	pass->prev_ctx = *prev_ctx;
 
 	matrix_projection(pass->projection_matrix, wlr_buffer->width, wlr_buffer->height,
 		WL_OUTPUT_TRANSFORM_FLIPPED_180);
diff --git a/render/gles2/renderer.c b/render/gles2/renderer.c
index 327d197e..1b106af5 100644
--- a/render/gles2/renderer.c
+++ b/render/gles2/renderer.c
@@ -433,6 +433,9 @@ static void gles2_destroy(struct wlr_renderer *wlr_renderer) {
 static struct wlr_render_pass *gles2_begin_buffer_pass(struct wlr_renderer *wlr_renderer,
 		struct wlr_buffer *wlr_buffer, const struct wlr_buffer_pass_options *options) {
 	struct wlr_gles2_renderer *renderer = gles2_get_renderer(wlr_renderer);
+
+	struct wlr_egl_context prev_ctx = {0};
+	wlr_egl_save_context(&prev_ctx);
 	if (!wlr_egl_make_current(renderer->egl)) {
 		return NULL;
 	}
@@ -448,7 +451,7 @@ static struct wlr_render_pass *gles2_begin_buffer_pass(struct wlr_renderer *wlr_
 		return NULL;
 	}
 
-	struct wlr_gles2_render_pass *pass = begin_gles2_buffer_pass(buffer, timer);
+	struct wlr_gles2_render_pass *pass = begin_gles2_buffer_pass(buffer, &prev_ctx, timer);
 	if (!pass) {
 		return NULL;
 	}