Split code a bit, wrangle OpenGL

Split system function hooks into hooks.h
Wrangle opengl functions instead of trying to use them directly.

1 files changed, 86 insertions, 0 deletions

diff --git a/glwrangle.h b/glwrangle.h
new file mode 100644
index 0000000..f6b2555
--- /dev/null
+++ b/glwrangle.h
@@ -0,0 +1,86 @@
+#pragma once
+
+static GLenum (*_glGetError)(void);
+static void (*_glGetIntegerv)(GLenum, GLint*);
+static GLboolean (*_glIsBuffer)(GLuint);
+static void (*_glGenBuffers)(GLsizei, GLuint*);
+static void (*_glDeleteBuffers)(GLsizei, GLuint*);
+static void (*_glBindBuffer)(GLenum, GLuint);
+static void (*_glBufferData)(GLenum, GLsizeiptr, const GLvoid*, GLenum);
+static void* (*_glMapBuffer)(GLenum, GLenum);
+static void (*_glUnmapBuffer)(GLenum);
+static void (*_glPixelStorei)(GLenum, GLint);
+static void (*_glReadPixels)(GLint, GLint, GLsizei, GLsizei, GLenum, GLenum, GLvoid*);
+static void (*_glPushClientAttrib)(GLbitfield);
+static void (*_glPopClientAttrib)(void);
+static void (*_glPushAttrib)(GLbitfield);
+static void (*_glPopAttrib)(void);
+static void (*_glEnable)(GLenum);
+static void (*_glDisable)(GLenum);
+static void (*_glScissor)(GLint, GLint, GLsizei, GLsizei);
+static void (*_glClearColor)(GLclampf, GLclampf, GLclampf, GLclampf);
+static void (*_glClear)(GLbitfield);
+
+#define glGetError _glGetError
+#define glGetIntegerv _glGetIntegerv
+#define glIsBuffer _glIsBuffer
+#define glGenBuffers _glGenBuffers
+#define glDeleteBuffers _glDeleteBuffers
+#define glBindBuffer _glBindBuffer
+#define glBufferData _glBufferData
+#define glMapBuffer _glMapBuffer
+#define glUnmapBuffer _glUnmapBuffer
+#define glPixelStorei _glPixelStorei
+#define glReadPixels _glReadPixels
+#define glPushClientAttrib _glPushClientAttrib
+#define glPopClientAttrib _glPopClientAttrib
+#define glPushAttrib _glPushAttrib
+#define glPopAttrib _glPopAttrib
+#define glEnable _glEnable
+#define glDisable _glDisable
+#define glScissor _glScissor
+#define glClearColor _glClearColor
+#define glClear _glClear
+
+static void
+load_gl_function_pointers(void* (*procs[])(const char*), const size_t memb)
+{
+   static bool loaded;
+
+   if (loaded)
+      return;
+
+   void* (*proc)(const char*);
+   for (size_t i = 0; i < memb; ++i) {
+      if ((proc = procs[i]))
+         break;
+   }
+
+   if (!proc)
+      ERRX(EXIT_FAILURE, "There is no proc loader available");
+
+#define GL(x) do { if (!(_##x = proc(#x))) { ERRX(EXIT_FAILURE, "Failed to load %s", #x); } } while (0)
+   GL(glGetError);
+   GL(glGetIntegerv);
+   GL(glIsBuffer);
+   GL(glGenBuffers);
+   GL(glDeleteBuffers);
+   GL(glBindBuffer);
+   GL(glBufferData);
+   GL(glMapBuffer);
+   GL(glUnmapBuffer);
+   GL(glPixelStorei);
+   GL(glReadPixels);
+   GL(glPushClientAttrib);
+   GL(glPopClientAttrib);
+   GL(glPushAttrib);
+   GL(glPopAttrib);
+   GL(glEnable);
+   GL(glDisable);
+   GL(glScissor);
+   GL(glClearColor);
+   GL(glClear);
+#undef GL
+
+   loaded = true;
+}