Deal with nontrivial image configurations

[libs/gl.git] / source / pixelstore.cpp

diff --git a/source/pixelstore.cpp b/source/pixelstore.cpp
new file mode 100644 (file)
index 0000000..c32cf60
--- /dev/null
+++ b/source/pixelstore.cpp
@@ -0,0 +1,62 @@
+#include <algorithm>
+#include "gl.h"
+#include "pixelformat.h"
+#include "pixelstore.h"
+
+using namespace std;
+
+namespace Msp {
+namespace GL {
+
+PixelStore::PixelStore():
+       row_length(0),
+       image_height(0),
+       skip_pixels(0),
+       skip_rows(0),
+       skip_images(0),
+       alignment(4)
+{ }
+
+PixelStore PixelStore::from_image(const Graphics::Image &img)
+{
+       PixelStore pstore;
+       unsigned stride = img.get_stride();
+       unsigned ncomp = get_component_count(pixelformat_from_graphics(img.get_format()));
+       pstore.set_canvas_size(img.get_stride()/ncomp, 0);
+       pstore.set_alignment(min(stride&~(stride-1), 8U));
+       return pstore;
+}
+
+void PixelStore::set_canvas_size(unsigned w, unsigned h)
+{
+       row_length = w;
+       image_height = h;
+}
+
+void PixelStore::set_origin(unsigned x, unsigned y, unsigned z)
+{
+       skip_pixels = x;
+       skip_rows = y;
+       skip_images = z;
+}
+
+void PixelStore::set_alignment(unsigned a)
+{
+       alignment = a;
+}
+
+void PixelStore::bind() const
+{
+       if(set_current(this))
+       {
+               glPixelStorei(GL_UNPACK_ROW_LENGTH, row_length);
+               glPixelStorei(GL_UNPACK_IMAGE_HEIGHT, image_height);
+               glPixelStorei(GL_UNPACK_SKIP_PIXELS, skip_pixels);
+               glPixelStorei(GL_UNPACK_SKIP_ROWS, skip_rows);
+               glPixelStorei(GL_UNPACK_SKIP_IMAGES, skip_images);
+               glPixelStorei(GL_UNPACK_ALIGNMENT, alignment);
+       }
+}
+
+} // namespace GL
+} // namespace Msp