From b81aff95e7924c38dbd1cf639011be1848af6967 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Sun, 10 Oct 2021 14:54:53 +0200
Subject: Enable alpha blending

---
 include/mgl/gl.h | 2 ++
 src/gl.c         | 4 +++-
 src/window.c     | 5 +++++
 tests/main.c     | 7 +++++++
 4 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/include/mgl/gl.h b/include/mgl/gl.h
index b5b6ca1..745e69d 100644
--- a/include/mgl/gl.h
+++ b/include/mgl/gl.h
@@ -18,6 +18,8 @@ typedef struct {
     void (*glViewport)(int x, int y, int width, int height);
     void (*glClearColor)(float red, float green, float blue, float alpha);
     void (*glClear)(unsigned int mask);
+    void (*glEnable)(unsigned int cap);
+    void (*glBlendFunc)(unsigned int sfactor, unsigned int dfactor);
 
     /* Optional*/
     void (*glXSwapIntervalEXT)(Display * dpy, GLXDrawable drawable, int interval);
diff --git a/src/gl.c b/src/gl.c
index 023ffbb..282046c 100644
--- a/src/gl.c
+++ b/src/gl.c
@@ -1,6 +1,6 @@
 #include "../include/mgl/gl.h"
 #include <dlfcn.h>
-/*#include <GL/glx.h>*/
+/*#include <GL/gl.h>*/
 #include <stdio.h>
 
 typedef struct {
@@ -37,6 +37,8 @@ int mgl_gl_load(mgl_gl *self) {
         { &self->glViewport, "glViewport" },
         { &self->glClearColor, "glClearColor" },
         { &self->glClear, "glClear" },
+        { &self->glEnable, "glEnable" },
+        { &self->glBlendFunc, "glBlendFunc" },
 
         { NULL, NULL }
     };
diff --git a/src/window.c b/src/window.c
index bdbcd6f..4d877d7 100644
--- a/src/window.c
+++ b/src/window.c
@@ -4,6 +4,9 @@
 #include <stdio.h>
 
 #define GL_COLOR_BUFFER_BIT 0x00004000
+#define GL_BLEND 0x0BE2
+#define GL_SRC_ALPHA 0x0302
+#define GL_ONE_MINUS_SRC_ALPHA 0x0303
 
 int mgl_window_create(mgl_window *self, const char *title, int width, int height, mgl_window_callback *callback, void *userdata) {
     return mgl_window_create_with_params(self, title, width, height, DefaultRootWindow(mgl_get_context()->connection), callback, userdata);
@@ -80,6 +83,8 @@ void mgl_window_show(mgl_window *self) {
     /* TODO: Switch current when rendering to another window, and set current to NULL when destroying the currently selected context */
     context->gl.glXMakeCurrent(context->connection, self->window, context->glx_context);
     set_vertical_sync_enabled(self->window, 1);
+    context->gl.glEnable(GL_BLEND);
+    context->gl.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     mgl_window_draw(self);
 }
 
diff --git a/tests/main.c b/tests/main.c
index dfea218..c16a68e 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -11,6 +11,13 @@ static void draw(mgl_window *window, void *userdata) {
         glColor3f(0., 0., 1.); glVertex3f( .75,  .75, 0.);
         glColor3f(1., 1., 0.); glVertex3f(-.75,  .75, 0.);
     glEnd();
+
+    glBegin(GL_QUADS);
+        glColor4f(1., 0., 0., 0.5); glVertex3f(0.1 + -.75, 0.1 + -.75, 0.);
+        glColor4f(1., 0., 0., 0.5); glVertex3f(0.1 +  .75, 0.1 + -.75, 0.);
+        glColor4f(1., 0., 0., 0.5); glVertex3f(0.1 +  .75, 0.1 +  .75, 0.);
+        glColor4f(1., 0., 0., 0.5); glVertex3f(0.1 + -.75, 0.1 +  .75, 0.);
+    glEnd();
 }
 
 int main(int argc, char **argv) {
-- 
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