add wlroots as a submodule for reference

Signed-off-by: Slendi <slendi@socopon.com>

src/LunarWM_wayland.c

@@ -26,6 +26,18 @@ static inline SphericalCoord get_forward_spherical_with_nearest(
 	return Vector3ToSpherical(vec);
 }
 
+static void LunarWM_Toplevel_release_surface_rt(LunarWM_Toplevel *tl)
+{
+	if (!tl)
+		return;
+	if (IsRenderTextureValid(tl->surface_rt)) {
+		UnloadRenderTexture(tl->surface_rt);
+	}
+	tl->surface_rt = (RenderTexture2D) { 0 };
+	tl->surface_extents = (struct wlr_box) { 0 };
+	tl->composed_has_alpha = false;
+}
+
 static void remove_windows_for_tl(LunarWM *wm, LunarWM_Toplevel *tl)
 {
 	if (!wm || !tl)
@@ -126,7 +138,9 @@ static void toplevel_unmap_notify(struct wl_listener *l, void *data)
 	tl->texture = NULL;
 	tl->gles_texture = NULL;
 	tl->rl_texture = (Texture) { 0 };
+	LunarWM_Toplevel_release_surface_rt(tl);
 	tl->surface = NULL;
+	tl->composed_has_alpha = false;
 
 	focus_fallback(tl->server);
 }
@@ -196,9 +210,63 @@ bool LunarWM_Toplevel_destroy(LunarWM_Toplevel *this)
 		wl_list_remove(&this->destroy.link);
 	if (this->locked_buffer)
 		wlr_buffer_unlock(this->locked_buffer);
+	LunarWM_Toplevel_release_surface_rt(this);
+	this->composed_has_alpha = false;
 	return true;
 }
 
+struct SurfaceComposeCtx {
+	struct wlr_box extents;
+	bool *has_alpha;
+};
+
+static void surface_compose_draw(
+    struct wlr_surface *surface, int sx, int sy, void *user_data)
+{
+	struct SurfaceComposeCtx *ctx = user_data;
+	if (!ctx)
+		return;
+
+	struct wlr_texture *wlr_tex = wlr_surface_get_texture(surface);
+	if (!wlr_tex || wlr_tex->width == 0 || wlr_tex->height == 0)
+		return;
+
+	struct wlr_gles2_texture *gles_tex = gles2_get_texture(wlr_tex);
+	if (!gles_tex)
+		return;
+	if (ctx->has_alpha && gles_tex->has_alpha)
+		*ctx->has_alpha = true;
+
+	struct wlr_gles2_texture_attribs attribs;
+	wlr_gles2_texture_get_attribs(wlr_tex, &attribs);
+	Texture2D tex = {
+		.id = (unsigned int)attribs.tex,
+		.width = (int)wlr_tex->width,
+		.height = (int)wlr_tex->height,
+		.mipmaps = 1,
+		.format = gles_tex->has_alpha
+		    ? PIXELFORMAT_UNCOMPRESSED_R8G8B8A8
+		    : PIXELFORMAT_UNCOMPRESSED_R8G8B8,
+	};
+
+	float dest_w = (float)surface->current.width;
+	float dest_h = (float)surface->current.height;
+	if (dest_w <= 0.0f || dest_h <= 0.0f) {
+		dest_w = (float)tex.width;
+		dest_h = (float)tex.height;
+	}
+
+	Rectangle src = { 0.0f, 0.0f, (float)tex.width, (float)tex.height };
+	Rectangle dst = {
+		(float)(sx - ctx->extents.x),
+		(float)(sy - ctx->extents.y),
+		dest_w,
+		dest_h,
+	};
+
+	DrawTexturePro(tex, src, dst, (Vector2) { 0.0f, 0.0f }, 0.0f, WHITE);
+}
+
 bool LunarWM_Toplevel_update(LunarWM_Toplevel *this)
 {
 	if (!this || !this->surface)
@@ -236,6 +304,53 @@ bool LunarWM_Toplevel_update(LunarWM_Toplevel *this)
 	SetTextureFilter(this->rl_texture, TEXTURE_FILTER_BILINEAR);
 	SetTextureWrap(this->rl_texture, TEXTURE_WRAP_CLAMP);
 
+	struct wlr_box extents = { 0 };
+	wlr_surface_get_extents(this->surface, &extents);
+	if (extents.width <= 0 || extents.height <= 0) {
+		LunarWM_Toplevel_release_surface_rt(this);
+		this->composed_has_alpha = this->gles_texture->has_alpha;
+		return true;
+	}
+
+	bool needs_alpha = this->gles_texture->has_alpha;
+	if (extents.x != 0 || extents.y != 0
+	    || extents.width != (int)this->texture->width
+	    || extents.height != (int)this->texture->height) {
+		needs_alpha = true;
+	}
+
+	bool const size_changed = !IsRenderTextureValid(this->surface_rt)
+	    || this->surface_rt.texture.width != extents.width
+	    || this->surface_rt.texture.height != extents.height;
+	if (size_changed) {
+		LunarWM_Toplevel_release_surface_rt(this);
+		this->surface_rt = LoadRenderTexture(extents.width, extents.height);
+		if (!IsRenderTextureValid(this->surface_rt)) {
+			this->composed_has_alpha = needs_alpha;
+			return true;
+		}
+		SetTextureFilter(this->surface_rt.texture, TEXTURE_FILTER_BILINEAR);
+		SetTextureWrap(this->surface_rt.texture, TEXTURE_WRAP_CLAMP);
+	}
+
+	BeginTextureMode(this->surface_rt);
+	ClearBackground(BLANK);
+	BeginBlendMode(BLEND_ALPHA);
+	struct SurfaceComposeCtx ctx = {
+		.extents = extents,
+		.has_alpha = &needs_alpha,
+	};
+	wlr_surface_for_each_surface(this->surface, surface_compose_draw, &ctx);
+	EndBlendMode();
+	EndTextureMode();
+
+	this->surface_extents = extents;
+	Texture2D composed = this->surface_rt.texture;
+	composed.width = extents.width;
+	composed.height = extents.height;
+	this->rl_texture = composed;
+	this->composed_has_alpha = needs_alpha;
+
 	return true;
 }
 
@@ -389,6 +504,7 @@ static void xwl_unmap_toplevel(LunarWM_Toplevel *tl)
 	tl->texture = NULL;
 	tl->gles_texture = NULL;
 	tl->rl_texture = (Texture) { 0 };
+	LunarWM_Toplevel_release_surface_rt(tl);
 	tl->surface = NULL;
 }