milek7/sim branch opengl 3.3 renderer import

gl/pbo.cpp

@@ -0,0 +1,65 @@
+#include "stdafx.h"
+#include "pbo.h"
+
+void gl::pbo::request_read(int x, int y, int lx, int ly, int pixsize, GLenum format, GLenum type)
+{
+    int s = lx * ly * pixsize;
+    if (s != size)
+        allocate(PIXEL_PACK_BUFFER, s, GL_STREAM_DRAW);
+    size = s;
+
+    data_ready = false;
+    sync.reset();
+
+    bind(PIXEL_PACK_BUFFER);
+    glReadPixels(x, y, lx, ly, format, type, 0);
+    unbind(PIXEL_PACK_BUFFER);
+
+    sync.emplace();
+}
+
+bool gl::pbo::read_data(int lx, int ly, void *data, int pixsize)
+{
+    is_busy();
+
+    if (!data_ready)
+        return false;
+
+    int s = lx * ly * pixsize;
+    if (s != size)
+        return false;
+
+    download(PIXEL_PACK_BUFFER, data, 0, s);
+    unbind(PIXEL_PACK_BUFFER);
+    data_ready = false;
+
+    return true;
+}
+
+bool gl::pbo::is_busy()
+{
+    if (!sync)
+        return false;
+
+    if (sync->is_signalled())
+    {
+        data_ready = true;
+        sync.reset();
+        return false;
+    }
+
+    return true;
+}
+
+void* gl::pbo::map(GLuint mode, targets target)
+{
+	bind(target);
+	return glMapBuffer(buffer::glenum_target(target), mode);
+}
+
+void gl::pbo::unmap(targets target)
+{
+	bind(target);
+	glUnmapBuffer(buffer::glenum_target(target));
+	sync.emplace();
+}