Display windows with minimal delay, locked to 60 fps

1 files changed, 185 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..d660e1d
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,185 @@
+#include "compositor.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdarg.h>
+
+#include <X11/Xlib.h>
+#include <X11/extensions/Xcomposite.h>
+#include <X11/extensions/Xfixes.h>
+#include <X11/extensions/shapeconst.h>
+
+static void fatal_if(bool condition, const char *fmt, ...) {
+    if(!condition)
+        return;
+
+    va_list args;
+    va_start(args, fmt);
+    fprintf(stderr, "fatal: ");
+    vfprintf(stderr, fmt, args);
+    fprintf(stderr, "\n");
+    va_end(args);
+    exit(1);
+}
+
+static int x_error_handler(Display *dpy, XErrorEvent *ee) {
+    (void)dpy;
+    (void)ee;
+    return 0;
+}
+
+static void glx_context_choose(Display *dpy, GLXFBConfig **configs, XVisualInfo **visual_info) {
+    const int visual_attribs[] = {
+        GLX_RENDER_TYPE, GLX_RGBA_BIT,
+        GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
+        GLX_DOUBLEBUFFER, True,
+        GLX_RED_SIZE, 8,
+        GLX_GREEN_SIZE, 8,
+        GLX_BLUE_SIZE, 8,
+        GLX_ALPHA_SIZE, 0,
+        GLX_DEPTH_SIZE, 0,
+        None,
+    };
+
+    int c;
+    *configs = glXChooseFBConfig(dpy, 0, visual_attribs, &c);
+    fatal_if(!configs, "failed to choose fb config");
+
+    for (int i = 0; i < c; i++) {
+        GLXFBConfig *config = configs[i];
+        XVisualInfo *visual = glXGetVisualFromFBConfig(dpy, *config);
+        if(!visual)
+            continue;
+
+        /*if(attr.depth != visual->depth) {
+            XFree(visual);
+            continue;
+        }*/
+        
+        *visual_info = visual;
+        *configs = config;
+        return;
+    }
+
+    fatal_if(true, "failed to find a valid fb config");
+}
+
+static void allow_input_passthrough(Display *dpy, Window w) {
+    XserverRegion region = XFixesCreateRegion(dpy, NULL, 0); 
+ 
+    XFixesSetWindowShapeRegion(dpy, w, ShapeBounding, 0, 0, 0); 
+    XFixesSetWindowShapeRegion(dpy, w, ShapeInput, 0, 0, region);
+
+    XFixesDestroyRegion (dpy, region);
+}
+
+static bool is_compositor_running(Display *dpy) {
+    Atom prop_atom = XInternAtom(dpy, "_NET_WM_CM_S0", False);
+    return XGetSelectionOwner(dpy, prop_atom) != None;
+}
+
+static void set_compositor_owner(Display *dpy, Window window) {
+    Atom prop_atom = XInternAtom(dpy, "_NET_WM_CM_S0", False);
+    XSetSelectionOwner(dpy, prop_atom, window, CurrentTime);
+}
+
+static bool x11_supports_composite_named_window_pixmap(Display *display) {
+    int extension_major;
+    int extension_minor;
+    if(!XCompositeQueryExtension(display, &extension_major, &extension_minor))
+        return false;
+
+    int major_version;
+    int minor_version;
+    return XCompositeQueryVersion(display, &major_version, &minor_version) && (major_version > 0 || minor_version >= 2);
+}
+
+int main(int argc, char **argv) {
+    /* Make nvidia act reasonably */
+    setenv("__GL_MaxFramesAllowed", "1", true);
+    setenv("__GL_YIELD", "", true);
+
+    Display *dpy = XOpenDisplay(NULL);
+    fatal_if(!dpy, "failed to connect to the X server");
+    XSetErrorHandler(x_error_handler);
+
+    fatal_if(!x11_supports_composite_named_window_pixmap(dpy), "your X server server is too old (Xcomposite extension version is less than 0.2)");
+    fatal_if(is_compositor_running(dpy), "another compositor is already running");
+
+    const Window root_window = DefaultRootWindow(dpy);
+    XSelectInput(dpy, root_window, SubstructureNotifyMask);
+
+    GLXFBConfig *fb_config;
+    XVisualInfo *xvisual_info;
+    glx_context_choose(dpy, &fb_config, &xvisual_info);
+    GLXContext glx_context = glXCreateNewContext(dpy, *fb_config, GLX_RGBA_TYPE, NULL, True);
+    fatal_if(!glx_context, "failed to create glx context");
+
+    //Colormap colormap = XCreateColormap(dpy, root_window, xvisual_info->visual, AllocNone);
+    //fatal_if(!colormap, "failed to create colormap");
+
+    const Window overlay_window = XCompositeGetOverlayWindow(dpy, root_window);
+    fatal_if(!overlay_window, "failed to get overlay window");
+    allow_input_passthrough(dpy, overlay_window);
+
+    // TODO: Create one window for each monitor
+    const int composite_window_width = WidthOfScreen(DefaultScreenOfDisplay(dpy));
+    const int composite_window_height = HeightOfScreen(DefaultScreenOfDisplay(dpy));
+    const Window composite_window = XCreateWindow(dpy, overlay_window, 0, 0, composite_window_width, composite_window_height, 0, CopyFromParent, InputOutput, CopyFromParent, 0, NULL);
+    fatal_if(!composite_window, "failed to create X window");
+    // TODO: Set window title to ngxc and other properties that are needed
+    set_compositor_owner(dpy, composite_window);
+
+    glXMakeContextCurrent(dpy, composite_window, composite_window, glx_context);
+
+    glXSwapIntervalEXT(dpy, composite_window, true);
+    glEnable(GL_TEXTURE_2D);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+    allow_input_passthrough(dpy, composite_window);
+    XMapWindow(dpy, composite_window);
+    XFlush(dpy);
+
+    // TODO: Also do this on monitor reconfigure
+    glViewport(0, 0, composite_window_width, composite_window_height);
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    glOrtho(0.0, composite_window_width, composite_window_height, 0.0, 0.0, 1.0);
+    glMatrixMode(GL_MODELVIEW);
+    glLoadIdentity();
+
+    ngxc_compositor compositor;
+    ngxc_compositor_init(&compositor, dpy, composite_window);
+
+    Window root_return, parent_return;
+    Window *children = NULL;
+    unsigned int num_children = 0;
+    XQueryTree(dpy, root_window, &root_return, &parent_return, &children, &num_children);
+
+    for(unsigned int i = 0; i < num_children; ++i) {
+        ngxc_compositor_add_window(&compositor, children[i]);
+    }
+
+    if(children)
+        XFree(children);
+
+    XEvent xev;
+    for(;;) {
+        while(XPending(dpy)) {
+            XNextEvent(dpy, &xev);
+            switch(xev.type) {
+                case ConfigureNotify: {
+                    /* TODO: Instead of doing this potentially multiple times at once, only do this for the last configure notify event for each window */
+                    ngxc_compositor_on_configure(&compositor, &xev.xconfigure);
+                    break;
+                }
+                default:
+                    break;
+            }
+        }
+        ngxc_compositor_render(&compositor);
+    }
+
+    return 0;
+}