tileset::tileset(std::string const& tsd_file_name)
{
p_read(tsd_file_name);
// Calculate vertics and indices for tileset
std::vector<vertex::pos2_tex2> vertices;
std::vector<GLuint> indices;
uvec2 const& texture_dim = p_texture->get_dimensions();
uvec2 const num_tiles = texture_dim / p_tile_size;
p_num_tiles = num_tiles.x() * num_tiles.y();
// Dimensions of a single tile when entire tileset is considered using coordinates [0, 1]
vec2 const tile_tex_coord_dim = vec2((float)p_tile_size) / vec2(texture_dim);
uvec2 curr_tile;
for(curr_tile.y() = 0; curr_tile.y() < num_tiles.y(); ++curr_tile.y())
{
for(curr_tile.x() = 0; curr_tile.x() < num_tiles.x(); ++curr_tile.x())
{
// Since size = current max index + 1, the index of the first vertex we add is equal to
// the size of the vector before it is added.
size_t curr_tile_base_vertex = vertices.size();
// Calculate the texture coordinates for this tile
vec2 tc_min = vec2(curr_tile) * tile_tex_coord_dim;
vec2 tc_max = tc_min + tile_tex_coord_dim;
vertices.emplace_back( vec2{-0.5f, -0.5f}, vec2{tc_min.x(), tc_max.y()} );
vertices.emplace_back( vec2{ 0.5f, -0.5f}, vec2{tc_max.x(), tc_max.y()} );
vertices.emplace_back( vec2{ 0.5f, 0.5f}, vec2{tc_max.x(), tc_min.y()} );
vertices.emplace_back( vec2{-0.5f, 0.5f}, vec2{tc_min.x(), tc_min.y()} );
GLuint bottom_left_index = curr_tile_base_vertex + 0;
GLuint bottom_right_index = curr_tile_base_vertex + 1;
GLuint top_right_index = curr_tile_base_vertex + 2;
GLuint top_left_index = curr_tile_base_vertex + 3;
indices.emplace_back(bottom_left_index);
indices.emplace_back(bottom_right_index);
indices.emplace_back(top_left_index);
indices.emplace_back(top_left_index);
indices.emplace_back(bottom_right_index);
indices.emplace_back(top_right_index);
}
}
p_tile_vertices.set_data(
vertices.data(),
vertices.size(),
indices.data(),
indices.size(),
GL_STATIC_DRAW);
}
inline uvec2 max(const uvec2& a, unsigned int b)
{
return uvec2( a.x() > b ? a.x() : b,
a.y() > b ? a.y() : b);
}
inline uvec2 max(const uvec2& a, const uvec2& b)
{
return uvec2( a.x() > b.x() ? a.x() : b.x(),
a.y() > b.y() ? a.y() : b.y());
}
inline uvec2 min(const uvec2& a, const uvec2& b)
{
return uvec2( a.x() < b.x() ? a.x() : b.x(),
a.y() < b.y() ? a.y() : b.y());
}
inline float dot(const uvec2& v1, const uvec2& v2) { return (float)(v1.x()*v2.x() + v1.y()*v2.y()); }