void TextureSource::get_texels_2x2(
TextureCache& texture_cache,
const int ix,
const int iy,
Color4f& t00,
Color4f& t10,
Color4f& t01,
Color4f& t11) const
{
const Vector<size_t, 2> p00 =
constrain_to_canvas(
m_texture_instance.get_addressing_mode(),
m_texture_props.m_canvas_width,
m_texture_props.m_canvas_height,
ix + 0,
iy + 0);
const Vector<size_t, 2> p11 =
constrain_to_canvas(
m_texture_instance.get_addressing_mode(),
m_texture_props.m_canvas_width,
m_texture_props.m_canvas_height,
ix + 1,
iy + 1);
const Vector<size_t, 2> p10(p11.x, p00.y);
const Vector<size_t, 2> p01(p00.x, p11.y);
// Compute the coordinates of the tile containing each texel.
const size_t tile_x_00 = truncate<size_t>(p00.x * m_texture_props.m_rcp_tile_width);
const size_t tile_y_00 = truncate<size_t>(p00.y * m_texture_props.m_rcp_tile_height);
const size_t tile_x_11 = truncate<size_t>(p11.x * m_texture_props.m_rcp_tile_width);
const size_t tile_y_11 = truncate<size_t>(p11.y * m_texture_props.m_rcp_tile_height);
// Check whether all four texels are part of the same tile.
const size_t tile_x_mask = tile_x_00 ^ tile_x_11;
const size_t tile_y_mask = tile_y_00 ^ tile_y_11;
if (tile_x_mask | tile_y_mask)
{
// Compute the tile space coordinates of each texel.
const size_t pixel_x_00 = p00.x - tile_x_00 * m_texture_props.m_tile_width;
const size_t pixel_y_00 = p00.y - tile_y_00 * m_texture_props.m_tile_height;
const size_t pixel_x_11 = p11.x - tile_x_11 * m_texture_props.m_tile_width;
const size_t pixel_y_11 = p11.y - tile_y_11 * m_texture_props.m_tile_height;
// Sample the tile.
sample_tile(texture_cache, m_assembly_uid, m_texture_uid, tile_x_00, tile_y_00, pixel_x_00, pixel_y_00, t00);
sample_tile(texture_cache, m_assembly_uid, m_texture_uid, tile_x_11, tile_y_00, pixel_x_11, pixel_y_00, t10);
sample_tile(texture_cache, m_assembly_uid, m_texture_uid, tile_x_00, tile_y_11, pixel_x_00, pixel_y_11, t01);
sample_tile(texture_cache, m_assembly_uid, m_texture_uid, tile_x_11, tile_y_11, pixel_x_11, pixel_y_11, t11);
}
else
{
// Compute the tile space coordinates of each texel.
const size_t org_x = tile_x_00 * m_texture_props.m_tile_width;
const size_t org_y = tile_y_00 * m_texture_props.m_tile_height;
const size_t pixel_x_00 = p00.x - org_x;
const size_t pixel_y_00 = p00.y - org_y;
const size_t pixel_x_11 = p11.x - org_x;
const size_t pixel_y_11 = p11.y - org_y;
// Retrieve the tile.
const Tile& tile =
texture_cache.get(
m_assembly_uid,
m_texture_uid,
tile_x_00,
tile_y_00);
// Sample the tile.
if (tile.get_channel_count() == 3)
{
Color3f rgb;
tile.get_pixel(pixel_x_00, pixel_y_00, rgb);
t00[0] = rgb[0];
t00[1] = rgb[1];
t00[2] = rgb[2];
t00[3] = 1.0f;
tile.get_pixel(pixel_x_11, pixel_y_00, rgb);
t10[0] = rgb[0];
t10[1] = rgb[1];
t10[2] = rgb[2];
t10[3] = 1.0f;
tile.get_pixel(pixel_x_00, pixel_y_11, rgb);
t01[0] = rgb[0];
t01[1] = rgb[1];
t01[2] = rgb[2];
t01[3] = 1.0f;
tile.get_pixel(pixel_x_11, pixel_y_11, rgb);
t11[0] = rgb[0];
t11[1] = rgb[1];
t11[2] = rgb[2];
t11[3] = 1.0f;
}
else
{
tile.get_pixel(pixel_x_00, pixel_y_00, t00);
tile.get_pixel(pixel_x_11, pixel_y_00, t10);
tile.get_pixel(pixel_x_00, pixel_y_11, t01);
tile.get_pixel(pixel_x_11, pixel_y_11, t11);
}
}
}
