can specify opengl version

src/args.c

@@ -7,12 +7,13 @@
 
 #include "types.h"
 
-#include "constants.h"
-
 #include "args.h"
 #include "config.h"
 #include "string.h"
 
+#define STR_IMPL_(x) #x     // stringify argument
+#define STR(x) STR_IMPL_(x) // indirection to expand argument macros
+
 static void print_help(int status_code) {
   puts(
       PACKAGE
@@ -48,6 +49,8 @@ static void print_help(int status_code) {
       "[--wayland] "
       "[--cocoa] "
       "[--win32] "
+      "[-oma=MAJOR] "
+      "[-omi=MINOR] "
       "\n\n"
       "Fusion Of Real-time Generative Effects.\n\n"
       "options:\n"
@@ -91,7 +94,13 @@ static void print_help(int status_code) {
       "  --x11                       force X11 GLFW backend\n"
       "  --wayland                   force Wayland GLFW backend\n"
       "  --cocoa                     force Cocoa GLFW backend\n"
-      "  --win32                     force Win32 GLFW backend\n");
+      "  --win32                     force Win32 GLFW backend\n"
+      "  -oma, --opengl-major-version      OpenGL major version "
+      "(default: " STR(
+          OPENGL_MAJOR_VERSION) ")\n"
+                                "  -omi, --opengl-minor-version      OpenGL "
+                                "minor version (default: " STR(
+                                    OPENGL_MINOR_VERSION) ")\n");
   exit(status_code);
 }
 
@@ -163,6 +172,8 @@ void args_parse(Parameters *params, int argc, char **argv) {
   params->trace_midi = false;
   params->trace_fps = false;
   params->glfw_backend = GLFW_BACKEND_ANY;
+  params->opengl_major = OPENGL_MAJOR_VERSION;
+  params->opengl_minor = OPENGL_MINOR_VERSION;
 
   for (int i = 1; i < argc; i++) {
     arg = argv[i];
@@ -239,6 +250,16 @@ void args_parse(Parameters *params, int argc, char **argv) {
       params->glfw_backend = GLFW_BACKEND_COCOA;
     } else if (is_arg(arg, "--win32")) {
       params->glfw_backend = GLFW_BACKEND_WIN32;
+    } else if (is_arg(arg, "-oma") || is_arg(arg, "--opengl-major-version")) {
+      params->opengl_major = parse_uint(arg, value);
+      if (params->opengl_major == 0) {
+        invalid_value(arg, value);
+      }
+    } else if (is_arg(arg, "-omi") || is_arg(arg, "--opengl-minor-version")) {
+      params->opengl_minor = parse_uint(arg, value);
+      if (params->opengl_major == 0) {
+        invalid_value(arg, value);
+      }
     } else {
 #ifdef VIDEO_IN
       if (is_arg(arg, "-vi") || is_arg(arg, "--video-in")) {

src/config.h

@@ -87,4 +87,23 @@
 #define MAX_TAP_VALUES 10
 #endif
 
+/* OPENGL */
+
+#ifndef OPENGL_MAJOR_VERSION
+#define OPENGL_MAJOR_VERSION 4
+#endif
+
+#ifndef OPENGL_MINOR_VERSION
+#define OPENGL_MINOR_VERSION 6
+#endif
+
+/* GLFW CONSTANTS */
+#ifndef GLFW_BACKENDS
+#define GLFW_BACKEND_ANY 0
+#define GLFW_BACKEND_X11 1
+#define GLFW_BACKEND_WAYLAND 2
+#define GLFW_BACKEND_COCOA 3
+#define GLFW_BACKEND_WIN32 4
+#endif
+
 #endif /* CONFIG_H */

src/constants.h

@@ -3,12 +3,6 @@
 #ifndef CONSTANTS_H
 #define CONSTANTS_H
 
-static const unsigned int GLFW_BACKEND_ANY = 0;
-static const unsigned int GLFW_BACKEND_X11 = 1;
-static const unsigned int GLFW_BACKEND_WAYLAND = 2;
-static const unsigned int GLFW_BACKEND_COCOA = 3;
-static const unsigned int GLFW_BACKEND_WIN32 = 4;
-
 static const char *vertex_shader_text =
     "#version 460\n"
     "const mat4 mvp = "

src/types.h

@@ -59,6 +59,8 @@ typedef struct Parameters {
   bool trace_midi;
   bool trace_fps;
   unsigned int glfw_backend;
+  unsigned int opengl_major;
+  unsigned int opengl_minor;
 } Parameters;
 
 // file.c

src/window.c

@@ -5,8 +5,6 @@
 
 #include "types.h"
 
-#include "constants.h"
-
 #include "window.h"
 
 static void init_glfw(void (*error_callback)(int, const char *),