MapleShrine/mkxp
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Eliminate GLEW dependency

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GL entrypoint resolution is now done manually. This has a couple
immediate benefits, such as not having to retrieve hundreds of
functions pointers that we'll never use. It's also nice to have
an exact overview of all the entrypoints used by mkxp.

This change allows mkxp to run fine with core contexts, not sure
how relevant that is going to be in the future.

What's noteworthy is that  _all_ entrypoints, even the ones core
in 1.1 and guaranteed to be in every libGL, are resolved
dynamically.
This has the added benefit of not having to link directly against
libGL anymore, which also cleans up the output of `ldd` quite
a bit (SDL2 loads most system deps dynamically at runtime).

GL headers are still required at build time.
This commit is contained in:
Jonas Kulla 2014-05-30 23:01:35 +02:00
parent 640b01e518
commit 6c481e5eb8
16 changed files with 470 additions and 272 deletions

86
src/main.cpp
View file

@ -19,7 +19,6 @@
** along with mkxp. If not, see <http://www.gnu.org/licenses/>.
*/
#include <glew.h>
#include <alc.h>
#include <SDL.h>
@ -34,6 +33,7 @@
#include "debuglogger.h"
#include "debugwriter.h"
#include "exception.h"
#include "gl-fun.h"
#include "binding.h"
@ -50,7 +50,7 @@ rgssThreadError(RGSSThreadData *rtData, const std::string &msg)
static inline const char*
glGetStringInt(GLenum name)
{
return (const char*) glGetString(name);
return (const char*) gl.GetString(name);
}
static void
@ -62,60 +62,6 @@ printGLInfo()
Debug() << "GLSL Version :" << glGetStringInt(GL_SHADING_LANGUAGE_VERSION);
}
static bool
setupOptionalGLExtensions(RGSSThreadData* threadData)
{
if (!GLEW_ARB_framebuffer_object)
{
if (!GLEW_EXT_framebuffer_object && !GLEW_EXT_framebuffer_blit)
{
rgssThreadError(threadData, "GL extensions \"GL_ARB_framebuffer_object\" or compatible extensiosns GL_EXT_framebuffer_object and GL_EXT_framebuffer_blit are not present");
return false;
}
else
{
/* setup compat */
/* From EXT_framebuffer_object */
glGenRenderbuffers = glGenRenderbuffersEXT;
glDeleteRenderbuffers = glDeleteRenderbuffersEXT;
glBindRenderbuffer = glBindRenderbufferEXT;
glRenderbufferStorage = glRenderbufferStorageEXT;
glGenFramebuffers = glGenFramebuffersEXT;
glDeleteFramebuffers = glDeleteFramebuffersEXT;
glBindFramebuffer = glBindFramebufferEXT;
glFramebufferTexture2D = glFramebufferTexture2DEXT;
glFramebufferRenderbuffer = glFramebufferRenderbufferEXT;
/* From EXT_framebuffer_blit */
glBlitFramebuffer = glBlitFramebufferEXT;
}
}
if (!GLEW_ARB_timer_query && GLEW_EXT_timer_query)
{
glGetQueryObjecti64v = glGetQueryObjecti64vEXT;
glGetQueryObjectui64v = glGetQueryObjectui64vEXT;
}
if (!GLEW_ARB_vertex_array_object )
{
if (!GLEW_APPLE_vertex_array_object)
{
rgssThreadError(threadData, "GL extensions \"GL_ARB_vertex_array_object\" or compatible extensions GL_APPLE_vertex_array_object are not present");
return false;
}
else
{
/* setup compat */
glBindVertexArray = glBindVertexArrayAPPLE;
/* the cast is because apple's uses const GLuint* and ARB doesn't */
glGenVertexArrays = (PFNGLGENVERTEXARRAYSPROC)glGenVertexArraysAPPLE;
glDeleteVertexArrays = glDeleteVertexArraysAPPLE;
}
}
return true;
}
int rgssThreadFun(void *userdata)
{
RGSSThreadData *threadData = static_cast<RGSSThreadData*>(userdata);
@ -136,36 +82,24 @@ int rgssThreadFun(void *userdata)
return 0;
}
if (glewInit() != GLEW_OK)
try
{
rgssThreadError(threadData, "Error initializing glew");
initGLFunctions();
}
catch (const Exception &exc)
{
rgssThreadError(threadData, exc.msg);
SDL_GL_DeleteContext(glCtx);
return 0;
}
glClearColor(0, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT);
gl.ClearColor(0, 0, 0, 1);
gl.Clear(GL_COLOR_BUFFER_BIT);
SDL_GL_SwapWindow(win);
printGLInfo();
/* Check for required GL version */
if (!GLEW_VERSION_2_0)
{
rgssThreadError(threadData, "At least OpenGL 2.0 is required");
SDL_GL_DeleteContext(glCtx);
return 0;
}
/* Setup optional GL extensions */
if (!setupOptionalGLExtensions(threadData))
{
SDL_GL_DeleteContext(glCtx);
return 0;
}
SDL_GL_SetSwapInterval(threadData->config.vsync ? 1 : 0);
DebugLogger dLogger;