src/objectrenderer.cpp

   1 /**
   2  * @file objectrenderer.cpp
   3  * @brief Implements ObjectRenderer and derived classes
   4  */
   5
   6 #include "objectrenderer.h"
   7 #include "view.h"
   8 #include <vector>
   9 #include <queue>
  10
  11 using namespace std;
  12
  13 namespace IPDF
  14 {
  15
  16 /**
  17  * ObjectRenderer constructor
  18  * Note we cannot compile the shaders in the ShaderProgram constructor
  19  *  because the Screen class needs to initialise GL first and it has a
  20  *      ShaderProgram member
  21  */
  22 ObjectRenderer::ObjectRenderer(const ObjectType & type,
  23                 const char * vert_glsl_file, const char * frag_glsl_file, const char * geom_glsl_file)
  24                 : m_type(type), m_shader_program(), m_indexes(), m_buffer_builder(NULL)
  25 {
  26         m_shader_program.InitialiseShaders(vert_glsl_file, frag_glsl_file, geom_glsl_file);
  27         m_shader_program.Use();
  28         glUniform4f(m_shader_program.GetUniformLocation("colour"), 0,0,0,1); //TODO: Allow different colours
  29 }
  30
  31 /**
  32  * Render using GPU
  33  */
  34 void ObjectRenderer::RenderUsingGPU(unsigned first_obj_id, unsigned last_obj_id)
  35 {
  36         // If we don't have anything to render, return.
  37         if (first_obj_id == last_obj_id) return;
  38         // If there are no objects of this type, return.
  39         if (m_indexes.empty()) return;
  40         unsigned first_index = 0;
  41         while (m_indexes.size() > first_index && m_indexes[first_index] < first_obj_id) first_index ++;
  42         unsigned last_index = first_index;
  43         while (m_indexes.size() > last_index && m_indexes[last_index] < last_obj_id) last_index ++;
  44
  45         m_shader_program.Use();
  46         m_ibo.Bind();
  47         glDrawElements(GL_LINES, (last_index-first_index)*2, GL_UNSIGNED_INT, (GLvoid*)(2*first_index*sizeof(uint32_t)));
  48 }
  49
  50
  51 /**
  52  * Default implementation for rendering using CPU
  53  */
  54 void ObjectRenderer::RenderUsingCPU(const Objects & objects, const View & view, const CPURenderTarget & target, unsigned first_obj_id, unsigned last_obj_id)
  55 {
  56         Error("Cannot render objects of type %d on CPU", m_type);
  57         //TODO: Render a rect or something instead?
  58 }
  59
  60 /**
  61  * Prepare index buffers for both CPU and GPU rendering to receive indexes (but don't add any yet!)
  62  */
  63 void ObjectRenderer::PrepareBuffers(unsigned max_objects)
  64 {
  65         if (m_buffer_builder != NULL) // We already have a BufferBuilder
  66         {
  67                 Fatal("Has been called before, without FinaliseBuffers being called since!");
  68         }
  69         // Empty and reserve the indexes vector (for CPU rendering)
  70         m_indexes.clear();
  71         m_indexes.reserve(max_objects); //TODO: Can probably make this smaller? Or leave it out? Do we care?
  72
  73         // Initialise and resize the ibo (for GPU rendering)
  74         m_ibo.Invalidate();
  75         m_ibo.SetUsage(GraphicsBuffer::BufferUsageStaticDraw);
  76         m_ibo.SetType(GraphicsBuffer::BufferTypeIndex);
  77         m_ibo.Resize(max_objects * 2 * sizeof(uint32_t));
  78         // BufferBuilder is used to construct the ibo
  79         m_buffer_builder = new BufferBuilder<uint32_t>(m_ibo.Map(false, true, true), m_ibo.GetSize()); // new matches delete in ObjectRenderer::FinaliseBuffers
  80
  81 }
  82
  83 /**
  84  * Add object index to the buffers for CPU and GPU rendering
  85  */
  86 void ObjectRenderer::AddObjectToBuffers(unsigned index)
  87 {
  88         if (m_buffer_builder == NULL) // No BufferBuilder!
  89         {
  90                 Fatal("Called without calling PrepareBuffers");
  91         }
  92         m_buffer_builder->Add(2*index); // ibo for GPU rendering
  93         m_buffer_builder->Add(2*index+1);
  94         m_indexes.push_back(index); // std::vector of indices for CPU rendering
  95 }
  96
  97 /**
  98  * Finalise the index buffers for CPU and GPU rendering
  99  */
 100 void ObjectRenderer::FinaliseBuffers()
 101 {
 102         if (m_buffer_builder == NULL) // No BufferBuilder!
 103         {
 104                 Fatal("Called without calling PrepareBuffers");
 105         }
 106         // For GPU rendering, UnMap the ibo
 107         m_ibo.UnMap();
 108         // ... and delete the BufferBuilder used to create it
 109         delete m_buffer_builder; // delete matches new in ObjectRenderer::PrepareBuffers
 110         m_buffer_builder = NULL;
 111
 112         // Nothing is necessary for CPU rendering
 113 }
 114
 115
 116 /**
 117  * Rectangle (filled)
 118  */
 119 void RectFilledRenderer::RenderUsingCPU(const Objects & objects, const View & view, const CPURenderTarget & target, unsigned first_obj_id, unsigned last_obj_id)
 120 {
 121         for (unsigned i = 0; i < m_indexes.size(); ++i)
 122         {
 123                 if (m_indexes[i] < first_obj_id) continue;
 124                 if (m_indexes[i] >= last_obj_id) continue;
 125                 PixelBounds bounds(CPURenderBounds(objects.bounds[m_indexes[i]], view, target));
 126                 FloodFillOnCPU(bounds.x+1, bounds.y+1, bounds, target, Colour(0,0,0,1));
 127                 /*
 128                 for (int64_t x = max((int64_t)0, bounds.x); x <= min(bounds.x+bounds.w, target.w-1); ++x)
 129                 {
 130                         for (int64_t y = max((int64_t)0, bounds.y); y <= min(bounds.y+bounds.h, target.h-1); ++y)
 131                         {
 132                                 int index = (x+target.w*y)*4;
 133                                 target.pixels[index+0] = 0;
 134                                 target.pixels[index+1] = 0;
 135                                 target.pixels[index+2] = 0;
 136                                 target.pixels[index+3] = 255;
 137                         }
 138                 }
 139                 */
 140         }
 141 }
 142
 143 /**
 144  * Rectangle (outine)
 145  */
 146 void RectOutlineRenderer::RenderUsingCPU(const Objects & objects, const View & view, const CPURenderTarget & target, unsigned first_obj_id, unsigned last_obj_id)
 147 {
 148         //Debug("Render %u outlined rectangles on CPU", m_indexes.size());
 149         for (unsigned i = 0; i < m_indexes.size(); ++i)
 150         {
 151                 if (m_indexes[i] < first_obj_id) continue;
 152                 if (m_indexes[i] >= last_obj_id) continue;
 153                 PixelBounds bounds(CPURenderBounds(objects.bounds[m_indexes[i]], view, target));
 154
 155                 // Using bresenham's lines now mainly because I want to see if they work
 156                 // top
 157                 ObjectRenderer::RenderLineOnCPU(bounds.x, bounds.y, bounds.x+bounds.w, bounds.y, target);
 158                 // bottom
 159                 ObjectRenderer::RenderLineOnCPU(bounds.x, bounds.y+bounds.h, bounds.x+bounds.w, bounds.y+bounds.h, target);
 160                 // left
 161                 ObjectRenderer::RenderLineOnCPU(bounds.x, bounds.y, bounds.x, bounds.y+bounds.h, target);
 162                 // right
 163                 ObjectRenderer::RenderLineOnCPU(bounds.x+bounds.w, bounds.y, bounds.x+bounds.w, bounds.y+bounds.h, target);
 164
 165                 // Diagonal for testing (from bottom left to top right)
 166                 //ObjectRenderer::RenderLineOnCPU(bounds.x,bounds.y+bounds.h, bounds.x+bounds.w, bounds.y,target, C_BLUE);
 167                 //ObjectRenderer::RenderLineOnCPU(bounds.x+bounds.w, bounds.y+bounds.h, bounds.x, bounds.y, target,C_GREEN);
 168         }
 169 }
 170
 171 /**
 172  * Circle (filled)
 173  */
 174 void CircleFilledRenderer::RenderUsingCPU(const Objects & objects, const View & view, const CPURenderTarget & target, unsigned first_obj_id, unsigned last_obj_id)
 175 {
 176         for (unsigned i = 0; i < m_indexes.size(); ++i)
 177         {
 178                 if (m_indexes[i] < first_obj_id) continue;
 179                 if (m_indexes[i] >= last_obj_id) continue;
 180                 PixelBounds bounds(CPURenderBounds(objects.bounds[m_indexes[i]], view, target));
 181                 int64_t centre_x = bounds.x + bounds.w / 2;
 182                 int64_t centre_y = bounds.y + bounds.h / 2;
 183
 184                 //Debug("Centre is %d, %d", centre_x, centre_y);
 185                 //Debug("Bounds are %d,%d,%d,%d", bounds.x, bounds.y, bounds.w, bounds.h);
 186                 //Debug("Windos is %d,%d", target.w, target.h);
 187                 for (int64_t x = max((int64_t)0, bounds.x); x <= min(bounds.x+bounds.w, target.w-1); ++x)
 188                 {
 189                         for (int64_t y = max((int64_t)0, bounds.y); y <= min(bounds.y + bounds.h, target.h-1); ++y)
 190                         {
 191                                 Real dx(2); dx *= Real(x - centre_x)/Real(bounds.w);
 192                                 Real dy(2); dy *= Real(y - centre_y)/Real(bounds.h);
 193                                 int64_t index = (x+target.w*y)*4;
 194
 195                                 if (dx*dx + dy*dy <= Real(1))
 196                                 {
 197                                         target.pixels[index+0] = 0;
 198                                         target.pixels[index+1] = 0;
 199                                         target.pixels[index+2] = 0;
 200                                         target.pixels[index+3] = 255;
 201                                 }
 202                         }
 203                 }
 204         }
 205 }
 206
 207 Rect ObjectRenderer::CPURenderBounds(const Rect & bounds, const View & view, const CPURenderTarget & target)
 208 {
 209         Rect result = view.TransformToViewCoords(bounds);
 210         result.x *= Real(target.w);
 211         result.y *= Real(target.h);
 212         result.w *= Real(target.w);
 213         result.h *= Real(target.h);
 214         return result;
 215 }
 216
 217 ObjectRenderer::PixelPoint ObjectRenderer::CPUPointLocation(const Vec2 & point, const View & view, const CPURenderTarget & target)
 218 {
 219         // hack...
 220         Rect result = view.TransformToViewCoords(Rect(point.x, point.y,1,1));
 221         int64_t x = result.x*target.w;
 222         int64_t y = result.y*target.h;
 223         return PixelPoint(x,y);
 224 }
 225
 226
 227 /**
 228  * Bezier curve
 229  * Not sure how to apply De'Casteljau, will just use a bunch of Bresnham lines for now.
 230  */
 231 void BezierRenderer::RenderUsingCPU(const Objects & objects, const View & view, const CPURenderTarget & target, unsigned first_obj_id, unsigned last_obj_id)
 232 {
 233         //Warn("Rendering Beziers on CPU. Things may explode.");
 234         for (unsigned i = 0; i < m_indexes.size(); ++i)
 235         {
 236                 if (m_indexes[i] < first_obj_id) continue;
 237                 if (m_indexes[i] >= last_obj_id) continue;
 238                 const Rect & bounds = objects.bounds[m_indexes[i]];
 239                 PixelBounds pix_bounds(CPURenderBounds(bounds,view,target));
 240
 241                 Bezier control(objects.beziers[objects.data_indices[m_indexes[i]]].ToAbsolute(bounds),CPURenderBounds(Rect(0,0,1,1), view, target));
 242                 //Debug("%s -> %s via %s", objects.beziers[objects.data_indices[m_indexes[i]]].Str().c_str(), control.Str().c_str(), bounds.Str().c_str());
 243                 // Draw a rectangle around the bezier for debugging the bounds rectangle calculations
 244                 if (view.ShowingObjectBounds())
 245                 {
 246                         ObjectRenderer::RenderLineOnCPU(pix_bounds.x, pix_bounds.y, pix_bounds.x+pix_bounds.w, pix_bounds.y, target, Colour(1,0,0,1));
 247                         ObjectRenderer::RenderLineOnCPU(pix_bounds.x, pix_bounds.y+pix_bounds.h, pix_bounds.x+pix_bounds.w, pix_bounds.y+pix_bounds.h, target, Colour(0,1,0,1));
 248                         ObjectRenderer::RenderLineOnCPU(pix_bounds.x, pix_bounds.y, pix_bounds.x, pix_bounds.y+pix_bounds.h, target, Colour(1,0,0,1));
 249                         ObjectRenderer::RenderLineOnCPU(pix_bounds.x+pix_bounds.w, pix_bounds.y, pix_bounds.x+pix_bounds.w, pix_bounds.y+pix_bounds.h, target, Colour(0,1,0,1));
 250                 }
 251                 // Draw lines between the control points for debugging
 252                 //ObjectRenderer::RenderLineOnCPU((int64_t)control.x0, (int64_t)control.y0, (int64_t)control.x1, (int64_t)control.y1,target);
 253                 //ObjectRenderer::RenderLineOnCPU((int64_t)control.x1, (int64_t)control.y1, (int64_t)control.x2, (int64_t)control.y2,target);
 254
 255
 256
 257                 Real x[2]; Real y[2];
 258                 control.Evaluate(x[0], y[0], Real(0));
 259                 //Debug("target is (%lu, %lu)", target.w, target.h);
 260                 int64_t blen = min(max((int64_t)2, (int64_t)(target.w/view.GetBounds().w)), (int64_t)100);
 261
 262                 Real invblen(1); invblen /= blen;
 263                 //Debug("Using %li lines, inverse %f", blen, Double(invblen));
 264                 for (int64_t j = 1; j <= blen; ++j)
 265                 {
 266                         control.Evaluate(x[j % 2],y[j % 2], invblen*j);
 267                         ObjectRenderer::RenderLineOnCPU((int64_t)Double(x[0]),(int64_t)Double(y[0]), (int64_t)Double(x[1]),(int64_t)Double(y[1]), target, Colour(0,0,0,!view.PerformingShading()));
 268                 }
 269
 270                 /*
 271                 Real u(0);
 272                 while (u < Real(1))
 273                 {
 274                         u += Real(1e-6);
 275                         Real x; Real y; control.Evaluate(x,y,u);
 276                         int64_t index = ((int64_t)x + (int64_t)y*target.w)*4;
 277                         if (index >= 0 && index < 4*(target.w*target.h))
 278                         {
 279                                 target.pixels[index+0] = 0;
 280                                 target.pixels[index+1] = 0;
 281                                 target.pixels[index+2] = 0;
 282                                 target.pixels[index+3] = 255;
 283                         }
 284                 }
 285                 */
 286
 287         }
 288 }
 289
 290 void BezierRenderer::PrepareBezierGPUBuffer(const Objects& objects)
 291 {
 292         m_bezier_coeffs.SetType(GraphicsBuffer::BufferTypeTexture);
 293         m_bezier_coeffs.SetUsage(GraphicsBuffer::BufferUsageDynamicDraw);
 294         m_bezier_coeffs.Resize(objects.beziers.size()*sizeof(GPUBezierCoeffs));
 295         BufferBuilder<GPUBezierCoeffs> builder(m_bezier_coeffs.Map(false, true, true), m_bezier_coeffs.GetSize());
 296
 297
 298         for (unsigned i = 0; i < objects.beziers.size(); ++i)
 299         {
 300                 const Bezier & bez = objects.beziers[i];
 301
 302                 GPUBezierCoeffs coeffs = {
 303                         Float(bez.x0), Float(bez.y0),
 304                         Float(bez.x1), Float(bez.y1),
 305                         Float(bez.x2), Float(bez.y2),
 306                         Float(bez.x3), Float(bez.y3)
 307                         };
 308                 builder.Add(coeffs);
 309         }
 310         m_bezier_coeffs.UnMap();
 311         glGenTextures(1, &m_bezier_buffer_texture);
 312         glBindTexture(GL_TEXTURE_BUFFER, m_bezier_buffer_texture);
 313         glTexBuffer(GL_TEXTURE_BUFFER, GL_RG32F, m_bezier_coeffs.GetHandle());
 314
 315         m_bezier_ids.SetType(GraphicsBuffer::BufferTypeTexture);
 316         m_bezier_ids.SetUsage(GraphicsBuffer::BufferUsageDynamicDraw);
 317         m_bezier_ids.Upload(objects.data_indices.size() * sizeof(uint32_t), &objects.data_indices[0]);
 318
 319         glGenTextures(1, &m_bezier_id_buffer_texture);
 320         glActiveTexture(GL_TEXTURE1);
 321         glBindTexture(GL_TEXTURE_BUFFER, m_bezier_id_buffer_texture);
 322         glTexBuffer(GL_TEXTURE_BUFFER, GL_R32I, m_bezier_ids.GetHandle());
 323         glActiveTexture(GL_TEXTURE0);
 324 }
 325
 326 void BezierRenderer::RenderUsingGPU(unsigned first_obj_id, unsigned last_obj_id)
 327 {
 328         if (!m_shader_program.Valid())
 329                 Warn("Shader is invalid (objects are of type %d)", m_type);
 330
 331         // If we don't have anything to render, return.
 332         if (first_obj_id == last_obj_id) return;
 333         // If there are no objects of this type, return.
 334         if (m_indexes.empty()) return;
 335
 336         unsigned first_index = 0;
 337         while (m_indexes.size() > first_index && m_indexes[first_index] < first_obj_id) first_index ++;
 338         unsigned last_index = first_index;
 339         while (m_indexes.size() > last_index && m_indexes[last_index] < last_obj_id) last_index ++;
 340
 341         m_shader_program.Use();
 342         glUniform1i(m_shader_program.GetUniformLocation("bezier_buffer_texture"), 0);
 343         glUniform1i(m_shader_program.GetUniformLocation("bezier_id_buffer_texture"), 1);
 344         m_ibo.Bind();
 345         glDrawElements(GL_LINES, (last_index-first_index)*2, GL_UNSIGNED_INT, (GLvoid*)(2*first_index*sizeof(uint32_t)));
 346 }
 347
 348
 349
 350 /**
 351  * Render Path (shading)
 352  */
 353 void PathRenderer::RenderUsingCPU(const Objects & objects, const View & view, const CPURenderTarget & target, unsigned first_obj_id, unsigned last_obj_id)
 354 {
 355         if (!view.ShowingObjectBounds() && !view.PerformingShading())
 356                 return;
 357
 358         for (unsigned i = 0; i < m_indexes.size(); ++i)
 359         {
 360                 if (m_indexes[i] < first_obj_id) continue;
 361                 if (m_indexes[i] >= last_obj_id) continue;
 362
 363
 364                 Rect bounds(CPURenderBounds(objects.bounds[m_indexes[i]], view, target));
 365                 PixelBounds pix_bounds(bounds);
 366                 const Path & path = objects.paths[objects.data_indices[m_indexes[i]]];
 367                 if (path.m_fill.a == 0 || !view.PerformingShading())
 368                         continue;
 369
 370                 for (unsigned f = 0; f < path.m_fill_points.size(); ++f)
 371                 {
 372                         PixelPoint fill_point(CPUPointLocation(path.m_fill_points[f], view, target));
 373                         FloodFillOnCPU(fill_point.first, fill_point.second, pix_bounds, target, path.m_fill);
 374                 }
 375
 376                 /*if (true)//(view.ShowingObjectBounds())
 377                 {
 378
 379                         PixelPoint start(CPUPointLocation((path.m_top+path.m_left+path.m_right+path.m_bottom)/4, view, target));
 380                         for (unsigned f = 0; f < path.m_fill_points.size(); ++f)
 381                         {
 382                                 PixelPoint end(CPUPointLocation(path.m_fill_points[f], view, target));
 383                                 RenderLineOnCPU(start.first, start.second, end.first, end.second, target, Colour(0,0,1,1));
 384                         }
 385                 }
 386                 */
 387
 388         }
 389 }
 390
 391 /**
 392  * For debug, save pixels to bitmap
 393  */
 394 void ObjectRenderer::SaveBMP(const CPURenderTarget & target, const char * filename)
 395 {
 396         SDL_Surface * surf = SDL_CreateRGBSurfaceFrom(target.pixels, target.w, target.h, 8*4, target.w*4,
 397         #if SDL_BYTEORDER == SDL_LIL_ENDIAN
 398                 0x000000ff, 0x0000ff00, 0x00ff0000, 0xff000000
 399         #else
 400                 0xff000000, 0x00ff0000, 0x0000ff00, 0x000000ff
 401         #endif //SDL_BYTEORDER
 402         );
 403         if (surf == NULL)
 404                 Fatal("SDL_CreateRGBSurfaceFrom(pixels...) failed - %s", SDL_GetError());
 405         if (SDL_SaveBMP(surf, filename) != 0)
 406                 Fatal("SDL_SaveBMP failed - %s", SDL_GetError());
 407
 408         // Cleanup
 409         SDL_FreeSurface(surf);
 410 }
 411
 412 /**
 413  * Bresenham's lines
 414  */
 415 void ObjectRenderer::RenderLineOnCPU(int64_t x0, int64_t y0, int64_t x1, int64_t y1, const CPURenderTarget & target, const Colour & colour, bool transpose)
 416 {
 417         int64_t dx = x1 - x0;
 418         int64_t dy = y1 - y0;
 419         bool neg_m = (dy*dx < 0);
 420         dy = abs(dy);
 421         dx = abs(dx);
 422
 423         // If positive slope > 1, just swap x and y
 424         if (dy > dx)
 425         {
 426                 RenderLineOnCPU(y0,x0,y1,x1,target,colour,!transpose);
 427                 return;
 428         }
 429
 430         int64_t two_dy = 2*dy;
 431         int64_t p = two_dy - dx;
 432         int64_t two_dxdy = 2*(dy-dx);
 433         int64_t x; int64_t y; int64_t x_end;
 434         int64_t width = (transpose ? target.h : target.w);
 435         int64_t height = (transpose ? target.w : target.h);
 436
 437         uint8_t rgba[4];
 438         rgba[0] = 255*colour.r;
 439         rgba[1] = 255*colour.g;
 440         rgba[2] = 255*colour.b;
 441         rgba[3] = 255*colour.a;
 442
 443         if (x0 > x1)
 444         {
 445                 x = x1;
 446                 y = y1;
 447                 x_end = x0;
 448         }
 449         else
 450         {
 451                 x = x0;
 452                 y = y0;
 453                 x_end = x1;
 454         }
 455
 456         if (x < 0)
 457         {
 458                 if (x_end < 0) return;
 459                 y = (neg_m ? y - (dy*-x)/dx : y + (dy*-x)/dx);
 460                 x = 0;
 461         }
 462
 463         if (x_end > width)
 464         {
 465                 if (x > width) return;
 466                 x_end = width-1;
 467         }
 468
 469         // TODO: Avoid extra inner conditionals
 470         do
 471         {
 472                 if (x >= 0 && x < width && y >= 0 && y < height)
 473                 {
 474                         int64_t index = (transpose ? (y + x*target.w)*4 : (x + y*target.w)*4);
 475                         for (int i = 0; i < 4; ++i)
 476                                 target.pixels[index+i] = rgba[i];
 477                 }
 478                 if (p < 0)
 479                         p += two_dy;
 480                 else
 481                 {
 482                         if (neg_m) --y; else ++y;
 483                         p += two_dxdy;
 484                 }
 485         } while (++x <= x_end);
 486 }
 487
 488 void ObjectRenderer::FloodFillOnCPU(int64_t x, int64_t y, const PixelBounds & bounds, const CPURenderTarget & target, const Colour & fill)
 489 {
 490         if (fill == Colour(1,1,1,1))
 491                 return;
 492         queue<PixelPoint > traverse;
 493         traverse.push(PixelPoint(x,y));
 494         // now with 100% less stack overflows!
 495         while (traverse.size() > 0)
 496         {
 497                 PixelPoint cur(traverse.front());
 498                 traverse.pop();
 499                 if (cur.first < 0 || cur.first < bounds.x || cur.first >= bounds.x+bounds.w || cur.first >= target.w ||
 500                         cur.second < 0 || cur.second < bounds.y || cur.second >= bounds.y+bounds.h || cur.second >= target.h)
 501                         continue;
 502                 if (GetColour(target, cur.first, cur.second) != Colour(1,1,1,1))
 503                         continue;
 504                 SetColour(target, cur.first, cur.second, fill);
 505
 506
 507                 traverse.push(PixelPoint(cur.first+1, cur.second));
 508                 traverse.push(PixelPoint(cur.first-1, cur.second));
 509                 traverse.push(PixelPoint(cur.first, cur.second-1));
 510                 traverse.push(PixelPoint(cur.first, cur.second+1));
 511         }
 512 }
 513
 514 }