source/pixelstore.cpp

   1 #include <algorithm>
   2 #include "gl.h"
   3 #include "pixelformat.h"
   4 #include "pixelstore.h"
   5
   6 using namespace std;
   7
   8 namespace Msp {
   9 namespace GL {
  10
  11 PixelStore::PixelStore():
  12         row_length(0),
  13         image_height(0),
  14         skip_pixels(0),
  15         skip_rows(0),
  16         skip_images(0),
  17         alignment(4)
  18 { }
  19
  20 PixelStore PixelStore::from_image(const Graphics::Image &img)
  21 {
  22         PixelStore pstore;
  23         unsigned stride = img.get_stride();
  24         unsigned ncomp = get_component_count(pixelformat_from_graphics(img.get_format()));
  25         pstore.set_canvas_size(img.get_stride()/ncomp, 0);
  26         pstore.set_alignment(min(stride&~(stride-1), 8U));
  27         return pstore;
  28 }
  29
  30 void PixelStore::update_parameter(int mask) const
  31 {
  32         if(cur_obj!=this)
  33                 return;
  34
  35         if(mask&SIZE)
  36         {
  37                 glPixelStorei(GL_UNPACK_ROW_LENGTH, row_length);
  38                 glPixelStorei(GL_UNPACK_IMAGE_HEIGHT, image_height);
  39         }
  40         if(mask&ORIGIN)
  41         {
  42                 glPixelStorei(GL_UNPACK_SKIP_PIXELS, skip_pixels);
  43                 glPixelStorei(GL_UNPACK_SKIP_ROWS, skip_rows);
  44                 glPixelStorei(GL_UNPACK_SKIP_IMAGES, skip_images);
  45         }
  46         if(mask&ALIGNMENT)
  47                 glPixelStorei(GL_UNPACK_ALIGNMENT, alignment);
  48 }
  49
  50 void PixelStore::set_canvas_size(unsigned w, unsigned h)
  51 {
  52         row_length = w;
  53         image_height = h;
  54         update_parameter(SIZE);
  55 }
  56
  57 void PixelStore::set_origin(unsigned x, unsigned y, unsigned z)
  58 {
  59         skip_pixels = x;
  60         skip_rows = y;
  61         skip_images = z;
  62         update_parameter(ORIGIN);
  63 }
  64
  65 void PixelStore::set_alignment(unsigned a)
  66 {
  67         alignment = a;
  68         update_parameter(ALIGNMENT);
  69 }
  70
  71 void PixelStore::bind() const
  72 {
  73         if(set_current(this))
  74                 update_parameter(-1);
  75 }
  76
  77 } // namespace GL
  78 } // namespace Msp