copy back front buffer to back buffer after swap to replicate behavior of copy back to frontHEADmaster

1 files changed, 44 insertions, 30 deletions

diff --git a/copy_pixels_swap_hack.c b/copy_pixels_swap_hack.c
index 653eeaf..2aff551 100644
--- a/copy_pixels_swap_hack.c
+++ b/copy_pixels_swap_hack.c
@@ -15,53 +15,67 @@
 #include <dlfcn.h>
 #include <GL/gl.h>
 #include <GL/glx.h>
+#include <X11/Xlib.h>
 void glCopyPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum type)
 {
 	static int first = 1;
-	static Display*    (*glx_get_current_display)(void) = NULL;
-	static GLXDrawable (*glx_get_current_drawable)(void) = NULL;
-	static void (*glx_swap_buffers)(Display*,GLXDrawable) = NULL;
-	static void (*gl_copy_pixels)(GLint,GLint,GLsizei,GLsizei,GLenum) = NULL;
-	static void (*gl_get_integerv)(GLenum,GLint*) = NULL;
-	static void (*gl_draw_buffer)(GLenum) = NULL;
-	static void (*gl_read_buffer)(GLenum) = NULL;
+	static Display*    (*glX_GetCurrentDisplay)(void) = NULL;
+	static GLXDrawable (*glX_GetCurrentDrawable)(void) = NULL;
+	static Status (*X_GetGeometry)(Display*,Drawable,Window*,int*,int*,unsigned*,unsigned*,unsigned*,unsigned*);
+	static void (*glX_SwapBuffers)(Display*,GLXDrawable) = NULL;
+	static void (*gl_WindowPos3i)(GLint,GLint,GLint) = NULL;
+	static void (*gl_CopyPixels)(GLint,GLint,GLsizei,GLsizei,GLenum) = NULL;
+	static void (*gl_GetIntegerv)(GLenum,GLint*) = NULL;
+	static void (*gl_DrawBuffer)(GLenum) = NULL;
+	static void (*gl_ReadBuffer)(GLenum) = NULL;
 	if( first ){
-		*(void**)(&glx_get_current_display) = dlsym(RTLD_NEXT, "glXGetCurrentDisplay");
-		*(void**)(&glx_get_current_drawable) = dlsym(RTLD_NEXT, "glXGetCurrentDrawable");
-		*(void**)(&glx_swap_buffers) = dlsym(RTLD_NEXT, "glXSwapBuffers");
-		*(void**)(&gl_copy_pixels) = dlsym(RTLD_NEXT, "glCopyPixels");
-		*(void**)(&gl_get_integerv) = dlsym(RTLD_NEXT, "glGetIntegerv");
-		*(void**)(&gl_draw_buffer) = dlsym(RTLD_NEXT, "glDrawBuffer");
-		*(void**)(&gl_read_buffer) = dlsym(RTLD_NEXT, "glReadBuffer");
+		*(void**)(&glX_GetCurrentDisplay)  = dlsym(RTLD_NEXT, "glXGetCurrentDisplay");
+		*(void**)(&glX_GetCurrentDrawable) = dlsym(RTLD_NEXT, "glXGetCurrentDrawable");
+		*(void**)(&glX_SwapBuffers)        = dlsym(RTLD_NEXT, "glXSwapBuffers");
+		*(void**)(&X_GetGeometry)          = dlsym(RTLD_NEXT, "XGetGeometry");
+		*(void**)(&gl_WindowPos3i)         = dlsym(RTLD_NEXT, "glWindowPos3i");
+		*(void**)(&gl_CopyPixels)          = dlsym(RTLD_NEXT, "glCopyPixels");
+		*(void**)(&gl_GetIntegerv)         = dlsym(RTLD_NEXT, "glGetIntegerv");
+		*(void**)(&gl_DrawBuffer)          = dlsym(RTLD_NEXT, "glDrawBuffer");
+		*(void**)(&gl_ReadBuffer)          = dlsym(RTLD_NEXT, "glReadBuffer");
 		first = 0;
 	}
 
 	Display *dpy;
 	GLXDrawable drw;
-	if( !glx_get_current_display || !glx_get_current_drawable
-	 || !gl_get_integerv || !gl_copy_pixels || !glx_swap_buffers
-	 || !gl_draw_buffer || !gl_read_buffer
-	 || !(dpy = glx_get_current_display())
-	 || !(drw = glx_get_current_drawable())
+	if( !glX_GetCurrentDisplay || !glX_GetCurrentDrawable || !glX_SwapBuffers
+	 || !gl_GetIntegerv || !gl_WindowPos3i || !gl_CopyPixels
+	 || !gl_DrawBuffer || !gl_ReadBuffer
+	 || !(dpy = glX_GetCurrentDisplay())
+	 || !(drw = glX_GetCurrentDrawable())
 	){
 		return;
 	}
 
 	GLint buffer_draw =  0;
 	GLint buffer_read = ~0;
-	gl_get_integerv(GL_DRAW_BUFFER, &buffer_draw);
-	gl_get_integerv(GL_READ_BUFFER, &buffer_read);
+	gl_GetIntegerv(GL_DRAW_BUFFER, &buffer_draw);
+	gl_GetIntegerv(GL_READ_BUFFER, &buffer_read);
 	if( GL_COLOR == type
-	 && buffer_draw == GL_FRONT
-	 && buffer_read == GL_BACK
+	 && GL_FRONT == buffer_draw
+	 && GL_BACK  == buffer_read
 	){
-		glx_swap_buffers(dpy, drw);
-		gl_draw_buffer(GL_BACK);
-		gl_read_buffer(GL_FRONT);
-		gl_copy_pixels(x,y,width,height,type);
-		gl_draw_buffer(GL_FRONT);
-		gl_read_buffer(GL_BACK);
+		GLint rp[4] = {0,0,0,0};
+		Window root;
+		int geom_x, geom_y;
+		unsigned geom_width, geom_height, border, depth;
+		gl_GetIntegerv(GL_CURRENT_RASTER_POSITION, rp);
+		X_GetGeometry(dpy, drw, &root, &geom_x, &geom_y, &geom_width, &geom_height, &border, &depth);
+
+		glX_SwapBuffers(dpy, drw);
+		gl_DrawBuffer(GL_BACK);
+		gl_ReadBuffer(GL_FRONT);
+		gl_WindowPos3i(0,0,0);
+		gl_CopyPixels(0, 0, geom_width, geom_height, type);
+		gl_DrawBuffer(GL_FRONT);
+		gl_ReadBuffer(GL_BACK);
+		gl_WindowPos3i(rp[0],rp[1],rp[2]);
 	} else {
-		gl_copy_pixels(x,y,width,height,type);
+		gl_CopyPixels(x,y,width,height,type);
 	}
 }