void App::read_write_pixel_buffer(clan::Canvas &canvas, clan::PixelBuffer &pbuff)
{
clan::ubyte64 time_now = clan::System::get_time();
pbuff.lock(canvas, clan::access_read_write);
if (pbuff.get_format() != clan::tf_rgba8)
throw clan::Exception("Expected the format to be RGBA8");
unsigned char *dptr = (unsigned char *) pbuff.get_data();
// Only write to a portion of the pixel buffer - To keep up the example speed
const int write_fraction = 2;
const int box_width = pbuff.get_width() / write_fraction;
const int box_height = pbuff.get_height() / write_fraction;
int next_line = (pbuff.get_width() - box_width) * pbuff.get_bytes_per_pixel();
dptr += pbuff.get_bytes_per_pixel() * pbuff.get_width() * ( (pbuff.get_height() - box_height) / 2);
dptr += pbuff.get_bytes_per_pixel() * (pbuff.get_width() - box_width) / 2;
for (int ycnt = 0; ycnt < box_height; ycnt++)
{
for (int xcnt = 0; xcnt < box_width; xcnt++)
{
unsigned char blue = dptr[0];
unsigned char red = dptr[1];
unsigned char green = dptr[2];
blue = red + xcnt + (time_now / 10);
green = red + xcnt*ycnt/512 + (time_now / 20);
*(dptr++) = blue;
*(dptr++) = red;
*(dptr++) = green;
*(dptr++) = 0xFF;
}
dptr += next_line;
}
pbuff.unlock();
}
clan::PixelBuffer App::convert_to_normalmap(clan::PixelBuffer &input)
{
if (input.get_format() != clan::tf_rgb8)
return input;
int width = input.get_width();
int height = input.get_height();
clan::PixelBuffer output(width, height, clan::tf_rgb8);
int in_pitch = input.get_pitch();
int out_pitch = output.get_pitch();
int in_bpp = input.get_bytes_per_pixel();
int out_bpp = output.get_bytes_per_pixel();
int pixel_tl;
int pixel_t;
int pixel_tr;
int pixel_r;
int pixel_br;
int pixel_b;
int pixel_bl;
int pixel_l;
int xpos_left;
int xpos_center;
int xpos_right;
int ypos_top;
int ypos_center;
int ypos_bottom;
for (int ypos = 0; ypos < height; ypos++)
{
unsigned char *in_ptr = (unsigned char *) input.get_data();
unsigned char *out_ptr = (unsigned char *) output.get_data();
for (int xpos = 0; xpos < width; xpos++)
{
// Wrap the coordinates
if (xpos != 0)
{
xpos_left = xpos - 1;
}else
{
xpos_left = width - 1;
}
if (ypos != 0)
{
ypos_top = ypos - 1;
}else
{
ypos_top = height - 1;
}
if (xpos != (width-1))
{
xpos_right = xpos + 1;
}else
{
xpos_right = 0;
}
if (ypos != (height-1))
{
ypos_bottom = ypos + 1;
}else
{
ypos_bottom = 0;
}
xpos_center = xpos;
ypos_center = ypos;
// Adjust the positions
xpos_left *= in_bpp;
xpos_center *= in_bpp;
xpos_right *= in_bpp;
ypos_top *= in_pitch;
ypos_center *= in_pitch;
ypos_bottom *= in_pitch;
// Get the pixels
pixel_tl = in_ptr[ xpos_left + ypos_top ];
pixel_l = in_ptr[ xpos_left + ypos_center ];
pixel_bl = in_ptr[ xpos_left + ypos_bottom ];
pixel_b = in_ptr[ xpos_center + ypos_bottom ];
pixel_br = in_ptr[ xpos_right + ypos_bottom ];
pixel_r = in_ptr[ xpos_right + ypos_center ];
pixel_tr = in_ptr[ xpos_right + ypos_top ];
pixel_t = in_ptr[ xpos_center + ypos_top ];
// Compute dx using Sobel:
// -1 0 1
// -2 0 2
// -1 0 1
int dX = pixel_tr + 2 * pixel_r + pixel_br - pixel_tl - 2 * pixel_l - pixel_bl;
// Compute dy using Sobel:
// -1 -2 -1
// 0 0 0
// 1 2 1
int dY = pixel_bl + 2 * pixel_b + pixel_br - pixel_tl - 2 * pixel_t - pixel_tr;
const float strength = 1.0f * 256.0f;
clan::Vec3f vector(dX, dY, strength);
vector.normalize();
// Stored as BGR
out_ptr[(xpos * out_bpp + ypos * out_pitch) + 2] = (int) (vector.x * 127.0f + 127.0f);
out_ptr[(xpos * out_bpp + ypos * out_pitch) + 1] = (int) (vector.y * 127.0f + 127.0f);
out_ptr[(xpos * out_bpp + ypos * out_pitch) + 0] = (int) (vector.z * 127.0f + 127.0f);
}
}
return output;
}