sketch out first bit of linux-backend of opengl-backend

2026-08-02 12:08:11 +00:00 · 2025-05-09 21:51:48 -07:00
parent 5939c3f010
commit a1318e6117
8 changed files with 205 additions and 19 deletions
@@ -0,0 +1,110 @@
+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+internal VoidProc *
+r_ogl_os_load_procedure(char *name)
+{
+  VoidProc *result = (VoidProc *)glXGetProcAddressARB((U8 *)name);
+  return result;
+}
+
+internal void
+r_ogl_os_init(CmdLine *cmdln)
+{
+  //- rjf: require GLX 1.3+
+  int glx_version_major = 0;
+  int glx_version_minor = 0;
+  if(!glXQueryVersion(os_lnx_gfx_state->display, &glx_version_major, &glx_version_minor) ||
+     (glx_version_major == 1 && glx_version_minor < 3) ||
+     glx_version_major < 1)
+  {
+    Temp scratch = scratch_begin(0, 0);
+    String8 message = push_str8f(scratch.arena, "Unsupported GLX version (%i.%i, need at least 1.3)", glx_version_major, glx_version_minor);
+    os_graphical_message(1, str8_lit("Fatal Error"), message);
+    os_abort(1);
+    scratch_end(scratch);
+  }
+  
+  //- rjf: get frame buffer configs
+  local_persist int framebuffer_config_options[] =
+  {
+    GLX_X_RENDERABLE,   1,
+    GLX_DRAWABLE_TYPE,  GLX_WINDOW_BIT,
+    GLX_RENDER_TYPE,    GLX_RGBA_BIT,
+    GLX_X_VISUAL_TYPE,  GLX_TRUE_COLOR,
+    GLX_RED_SIZE,       8,
+    GLX_GREEN_SIZE,     8,
+    GLX_BLUE_SIZE,      8,
+    GLX_ALPHA_SIZE,     8,
+    GLX_DEPTH_SIZE,     24,
+    GLX_STENCIL_SIZE,   8,
+    GLX_DOUBLEBUFFER,   1,
+    None
+  };
+  int framebuffer_configs_count = 0;
+  GLXFBConfig *framebuffer_configs = glXChooseFBConfig(os_lnx_gfx_state->display, DefaultScreen(os_lnx_gfx_state->display), framebuffer_config_options, &framebuffer_configs_count);
+  if(framebuffer_configs == 0)
+  {
+    os_graphical_message(1, str8_lit("Fatal Error"), str8_lit("Could not find a suitable framebuffer configuration."));
+    os_abort(1);
+  }
+  GLXFBConfig framebuffer_config = framebuffer_configs[0];
+  XFree(framebuffer_configs);
+  
+  //- rjf: get visual info; create color map
+  XVisualInfo *visual_info = glXGetVisualFromFBConfig(os_lnx_gfx_state->display, framebuffer_config);
+  Colormap cmap = XCreateColormap(os_lnx_gfx_state->display, RootWindow(os_lnx_gfx_state->display, visual_info->screen), visual_info->visual, AllocNone);
+  
+  //- rjf: construct set-window-attributes
+  XSetWindowAttributes set_window_attributes = {0};
+  set_window_attributes.background_pixmap = None;
+  set_window_attributes.border_pixel      = 0;
+  set_window_attributes.event_mask        = StructureNotifyMask;
+  
+  //- rjf: construct context
+  {
+    B32 debug_mode = cmd_line_has_flag(cmdln, str8_lit("opengl_debug"));
+#if BUILD_DEBUG
+    debug_mode = 1;
+#endif
+    glXCreateContextAttribsARBProc glXCreateContextAttribsARB = 0;
+    glXCreateContextAttribsARB = (glXCreateContextAttribsARBProc)glXGetProcAddressARB((U8 *)"glXCreateContextAttribsARB");
+    int context_options[] =
+    {
+      GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
+      GLX_CONTEXT_MINOR_VERSION_ARB, 3,
+      GLX_CONTEXT_FLAGS_ARB,         !!debug_mode*GLX_CONTEXT_DEBUG_BIT_ARB,
+      None
+    };
+    r_ogl_lnx_ctx = glXCreateContextAttribsARB(os_lnx_gfx_state->display, framebuffer_config, 0, 1, context_options);
+  }
+  
+  glXMakeCurrent(os_lnx_gfx_state->display, None, r_ogl_lnx_ctx);
+}
+
+internal R_Handle
+r_ogl_os_window_equip(OS_Handle window)
+{
+  R_Handle result = {0};
+  return result;
+}
+
+internal void
+r_ogl_os_window_unequip(OS_Handle os, R_Handle r)
+{
+  
+}
+
+internal void
+r_ogl_os_select_window(OS_Handle os, R_Handle r)
+{
+  OS_LNX_Window *w = (OS_LNX_Window *)os.u64[0];
+  glXMakeCurrent(os_lnx_gfx_state->display, w->window, r_ogl_lnx_ctx);
+}
+
+internal void
+r_ogl_os_window_swap(OS_Handle os, R_Handle r)
+{
+  OS_LNX_Window *w = (OS_LNX_Window *)os.u64[0];
+  glXSwapBuffers(os_lnx_gfx_state->display, w->window);
+}
@@ -0,0 +1,25 @@
+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+#ifndef RENDER_OPENGL_LINUX_H
+#define RENDER_OPENGL_LINUX_H
+
+#define glTexImage3D glTexImage3D__static
+#define glTexSubImage3D glTexSubImage3D__static
+#define glActiveTexture glActiveTexture__static
+#include <GL/gl.h>
+#include <GL/glx.h>
+#undef glTexImage3D
+#undef glTexSubImage3D
+#undef glActiveTexture
+
+#define GLX_CONTEXT_MAJOR_VERSION_ARB          0x2091
+#define GLX_CONTEXT_MINOR_VERSION_ARB          0x2092
+#define GLX_CONTEXT_FLAGS_ARB                  0x2094
+#define GLX_CONTEXT_DEBUG_BIT_ARB              0x00000001
+#define GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB 0x00000002
+typedef GLXContext (*glXCreateContextAttribsARBProc)(Display*, GLXFBConfig, GLXContext, Bool, const int*);
+
+global GLXContext r_ogl_lnx_ctx = 0;
+
+#endif // RENDER_OPENGL_LINUX_H