2d图形旋转
1.这里旋转使用数学公式:
xr = x * cos(theta) - y * sin(theta);
yr = x * sin(theta) + y * cos(theta);
2.如果以左上角为原点(0,0)，x方向向右增加,y方向向下增加的话，对于原图形旋转的100度并不等于连续20次的旋转5度的结果，可以举例对比一下。
3.memcpy对于复制对象真的很好用。
4.在这里我重画背景使用的是gdi的FillRect:
HDC hdc;
lpddsprimary->GetDC(&hdc);
FillRect(hdc, &client, (HBRUSH)GetStockObject(WHITE_BRUSH));
lpddsprimary->ReleaseDC(hdc);
该程序以左上角(0,0)为原点，支持移动、改变窗口大小重画360°图形。
#include <Windows.h>
#include <ddraw.h>
#include <math.h>#pragma comment(lib, "ddraw.lib")
#pragma comment(lib, "dxguid.lib")#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 480
#define SCREEN_BPP 32
#define SCREEN_WIDTH 1920
#define SCREEN_HEIGHT 1080
#define KEY_DOWN(vk_code) (GetAsyncKeyState(vk_code) & 0x8000 ? 1 : 0)
#define KEY_UP(vk_code) (GetAsyncKeyState(vk_code) & 0x8000 ? 0 : 1)#define CLIP_CODE_C 0x0000
#define CLIP_CODE_N 0x0008
#define CLIP_CODE_S 0x0004
#define CLIP_CODE_E 0x0002
#define CLIP_CODE_W 0x0001#define CLIP_CODE_NE 0x000a
#define CLIP_CODE_SE 0x0006
#define CLIP_CODE_NW 0x0009
#define CLIP_CODE_SW 0x0005typedef struct VERTEX2DI_TYP
{int x, y;
}VERTEX2DI, * VERTEX2DI_PTR;typedef struct POLYGON2D_TYP
{int state;int num_verts;int x0, y0;int xv, yv;LONG color;VERTEX2DI* vlist;
} POLYGON2D, * POLYGON2D_PTR;HWND main_hwnd = nullptr;
RECT client;
LPDIRECTDRAW7 lpdd7 = nullptr;
LPDIRECTDRAWSURFACE7 lpddsprimary = nullptr;
LPDIRECTDRAWCLIPPER lpddclipper = nullptr;
DDSURFACEDESC2 ddsd;
int pixel;
int window_close = 0;
POLYGON2D triangles[4];
float cos_look[360];
float sin_look[360];
int theta = -5; //旋转度数int Game_Init(void* params = nullptr, int num_params = 0);
int Game_Main(void* params = nullptr, int num_params = 0);
int Game_Shutdown(void* params = nullptr, int num_params = 0);
int Draw_Line(int x1, int y1, int x2, int y2, LONG color, LONG* vb_start, int iPitch);
int Clip_Line(int& x1, int& y1, int& x2, int& y2);
int GetInterSectionPoint(int p_code, int& xc, int& yc, int x1, int y1, int x2, int y2, int min_clip_x, int min_clip_y, int max_clip_x, int max_clip_y);
int Draw_Clip_Line(int x1, int y1, int x2, int y2, LONG color, LONG* vb_start, int iPitch);
int Draw_Polygon2D(POLYGON2D_PTR poly, LONG* vb_strat, int iPitch);
int Rotate_Polygon2D(POLYGON2D_PTR poly, int theta);LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{TCHAR szAppName[] = TEXT("normal window");MSG msg;WNDCLASS wndclass;wndclass.style = CS_VREDRAW | CS_HREDRAW;wndclass.lpfnWndProc = WndProc;wndclass.cbClsExtra = 0;wndclass.cbWndExtra = 0;wndclass.hInstance = hInstance;wndclass.hIcon = LoadIcon(nullptr, IDI_APPLICATION);wndclass.hCursor = LoadCursor(nullptr, IDC_ARROW);wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.lpszMenuName = nullptr;wndclass.lpszClassName = szAppName;if (!RegisterClass(&wndclass)){MessageBox(nullptr, TEXT("Register Class Failed"), szAppName, MB_ICONERROR);return 0;}client = {0, 0, WINDOW_WIDTH-1, WINDOW_HEIGHT-1};AdjustWindowRect(&client, WS_OVERLAPPEDWINDOW, false);main_hwnd = CreateWindow(szAppName, TEXT("normal_window"), WS_OVERLAPPEDWINDOW | WS_VISIBLE,CW_USEDEFAULT, CW_USEDEFAULT, client.right - client.left, client.bottom - client.top,nullptr, nullptr, hInstance, nullptr);Game_Init();while (true){if (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE)){if (msg.message == WM_QUIT)break;TranslateMessage(&msg);DispatchMessage(&msg);}Game_Main();}Game_Shutdown();return msg.wParam;
}LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{HDC hdc;PAINTSTRUCT ps;int xPos;int yPos;switch (message){case WM_CREATE://createreturn 0;case WM_SIZE://change sizetheta = -5;return 0;case WM_MOVE://movetheta = -5;return 0;case WM_LBUTTONDOWN:xPos = LOWORD(lParam);yPos = HIWORD(lParam);return 0;case WM_PAINT:hdc = BeginPaint(hwnd, &ps);//drawEndPaint(hwnd, &ps);return 0;case WM_DESTROY:window_close = 1;PostQuitMessage(0);return 0;}return DefWindowProc(hwnd, message, wParam, lParam);
}int Game_Init(void* params, int num_params)
{if (FAILED(DirectDrawCreateEx(nullptr, (LPVOID*)&lpdd7, IID_IDirectDraw7, nullptr)))return 0;lpdd7->SetCooperativeLevel(main_hwnd, DDSCL_NORMAL);memset(&ddsd, 0, sizeof(ddsd));ddsd.dwSize = sizeof(ddsd);ddsd.dwFlags = DDSD_CAPS;ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;if (FAILED(lpdd7->CreateSurface(&ddsd, &lpddsprimary, nullptr)))return 0;//获取像素格式DDPIXELFORMAT ddpixelformat;memset(&ddpixelformat, 0, sizeof(ddpixelformat));ddpixelformat.dwSize = sizeof(ddpixelformat);lpddsprimary->GetPixelFormat(&ddpixelformat);pixel = ddpixelformat.dwRGBBitCount;if (FAILED(lpdd7->CreateClipper(0, &lpddclipper, nullptr)))return 0;if (FAILED(lpddclipper->SetHWnd(0, main_hwnd)))return 0;if (FAILED(lpddsprimary->SetClipper(lpddclipper)))return 0;//init trianglesfor (int i = 0; i < 4; i++){triangles[i].state = 1;triangles[i].num_verts = 4;RECT rect = { 300 + i * 50, 300 + i * 50, 300 + i * 50 + 50, 300 + i * 50 + 50 };triangles[i].x0 = (rect.left + rect.right) / 2;triangles[i].y0 = (rect.top + rect.bottom) / 2;triangles[i].xv = triangles[i].yv = 10;triangles[i].color = RGB(rand() % 256, rand() % 256, rand() % 256);triangles[i].vlist = new VERTEX2DI[triangles[i].num_verts];triangles[i].vlist[0] = { rect.left, rect.top };triangles[i].vlist[1] = { rect.right, rect.top };triangles[i].vlist[2] = { rect.right, rect.bottom };triangles[i].vlist[3] = { rect.left, rect.bottom };}//generate the tablesfor (int ang = 0; ang < 360; ang++){float theta = (float)ang * 3.14159 / 180;sin_look[ang] = sin(theta);cos_look[ang] = cos(theta);}return 1;
}int Game_Main(void* params, int num_params)
{DDBLTFX ddbltfx;if (KEY_DOWN(VK_ESCAPE)){window_close = 1;SendMessage(main_hwnd, WM_CLOSE, 0, 0);return 0;}if (window_close)return 0;//GetClientRect(main_hwnd, &client);GetWindowRect(main_hwnd, &client);if (theta == -5) //界面初始化为白色{HDC hdc;lpddsprimary->GetDC(&hdc);FillRect(hdc, &client, (HBRUSH)GetStockObject(WHITE_BRUSH));lpddsprimary->ReleaseDC(hdc);}memset(&ddsd, 0, sizeof(ddsd));ddsd.dwSize = sizeof(ddsd);if (FAILED(lpddsprimary->Lock(nullptr, &ddsd, DDLOCK_SURFACEMEMORYPTR | DDLOCK_WAIT, nullptr)))return 0;LONG* video_buffer = (LONG*)ddsd.lpSurface;int ipitch = ddsd.lPitch;if (pixel == 32){if (theta < 355){theta += 5;if (theta == 360){int x = 0;}//init temp_trianglesPOLYGON2D temp_triangles[4];memcpy(temp_triangles, triangles, sizeof(triangles));for (int i = 0; i < 4; i++){temp_triangles[i].vlist = new VERTEX2DI[temp_triangles[i].num_verts];memcpy(temp_triangles[i].vlist, triangles[i].vlist, temp_triangles[i].num_verts * sizeof(VERTEX2DI));}for (int i = 0; i < 4; i++){Rotate_Polygon2D(temp_triangles + i, theta);Draw_Polygon2D(temp_triangles + i, video_buffer, ipitch >> 2);}//destroy temp_triangles.vlistfor (int i = 0; i < 4; i++)delete[] temp_triangles[i].vlist;}}if (FAILED(lpddsprimary->Unlock(nullptr)))return 0;//Sleep(10000);return 1;
}int Game_Shutdown(void* params, int num_params)
{if (lpddsprimary){lpddsprimary->Release();lpddsprimary = nullptr;}if (lpddclipper){lpddclipper->Release();lpddclipper = nullptr;}if (lpdd7){lpdd7->Release();lpdd7 = nullptr;}//destroy trianglesfor (int i = 0; i < 4; i++)delete[] triangles[i].vlist;return 1;
}int Draw_Line(int x1, int y1, int x2, int y2, LONG color, LONG* vb_start, int iPitch)
{int dx = x2 - x1;int dy = y2 - y1;int inx, iny, dx2, dy2, error;if (dx >= 0)inx = 1;else{inx = -1;dx = -dx;}if (dy >= 0)iny = iPitch;else{iny = -iPitch;dy = -dy;}dx2 = dx << 1;dy2 = dy << 1;vb_start += x1 + y1 * iPitch;if (dx > dy){error = dy2 - dx;for (int i = 0; i <= dx; i++){*vb_start = color;if (error >= 0){error -= dx2;vb_start += iny;}error += dy2;vb_start += inx;}}else{error = dx2 - dy;for (int i = 0; i <= dy; i++){*vb_start = color;if (error >= 0){error -= dy2;vb_start += inx;}error += dx2;vb_start += iny;}}return 1;
}int Clip_Line(int& x1, int& y1, int& x2, int& y2)
{int min_clip_x = client.left;int min_clip_y = client.top;int max_clip_x = client.right;int max_clip_y = client.bottom;int xc1 = x1, yc1 = y1, xc2 = x2, yc2 = y2;int p1_code = 0, p2_code = 0;if (y1 < min_clip_y)p1_code |= CLIP_CODE_N;else if (y1 > max_clip_y)p1_code |= CLIP_CODE_S;if (x1 < min_clip_x)p1_code |= CLIP_CODE_W;else if (x1 > max_clip_x)p1_code |= CLIP_CODE_E;if (y2 < min_clip_y)p2_code |= CLIP_CODE_N;else if (y2 > max_clip_y)p2_code |= CLIP_CODE_S;if (x2 < min_clip_x)p2_code |= CLIP_CODE_W;else if (x2 > max_clip_x)p2_code |= CLIP_CODE_E;if (p1_code & p2_code)return 0;if (p1_code == 0 && p2_code == 0)return 1;int iSpStatus1 = GetInterSectionPoint(p1_code, xc1, yc1, x1, y1, x2, y2, min_clip_x, min_clip_y, max_clip_x, max_clip_y);int iSpStatus2 = GetInterSectionPoint(p2_code, xc2, yc2, x1, y1, x2, y2, min_clip_x, min_clip_y, max_clip_x, max_clip_y);if (!(iSpStatus1 | iSpStatus2))return 0;x1 = xc1;y1 = yc1;x2 = xc2;y2 = yc2;return 1;
}int GetInterSectionPoint(int p_code, int& xc, int& yc, int x1, int y1, int x2, int y2, int min_clip_x, int min_clip_y, int max_clip_x, int max_clip_y)
{switch (p_code){case CLIP_CODE_N:yc = min_clip_y;xc = x1 + (min_clip_y - y1) * (x2 - x1) / (y2 - y1);break;case CLIP_CODE_S:yc = max_clip_y;xc = x1 + (max_clip_y - y1) * (x2 - x1) / (y2 - y1);break;case CLIP_CODE_W:xc = min_clip_x;yc = y1 + (min_clip_x - x1) * (y2 - y1) / (x2 - x1);break;case CLIP_CODE_E:xc = max_clip_x;yc = y1 + (max_clip_x - x1) * (y2 - y1) / (x2 - x1);break;case CLIP_CODE_NW:yc = min_clip_y;xc = x1 + (min_clip_y - y1) * (x2 - x1) / (y2 - y1);if (xc < min_clip_x){xc = min_clip_x;yc = y1 + (min_clip_x - x1) * (y2 - y1) / (x2 - x1);}break;case CLIP_CODE_SW:yc = max_clip_y;xc = x1 + (max_clip_y - y1) * (x2 - x1) / (y2 - y1);if (xc < min_clip_x){xc = min_clip_x;yc = y1 + (min_clip_x - x1) * (y2 - y1) / (x2 - x1);}break;case CLIP_CODE_NE:yc = min_clip_y;xc = x1 + (min_clip_y - y1) * (x2 - x1) / (y2 - y1);if (xc > max_clip_x){xc = max_clip_x;yc = y1 + (max_clip_x - x1) * (y2 - y1) / (x2 - x1);}break;case CLIP_CODE_SE:yc = max_clip_y;xc = x1 + (max_clip_y - y1) * (x2 - x1) / (y2 - y1);if (xc > max_clip_x){xc = max_clip_x;yc = y1 + (max_clip_x - x1) * (y2 - y1) / (x2 - x1);}break;}if (xc < min_clip_x || xc > max_clip_x || yc < min_clip_y || yc > max_clip_y)return 0;return 1;
}int Draw_Clip_Line(int x1, int y1, int x2, int y2, LONG color, LONG* vb_start, int iPitch)
{int iDcStatus = Clip_Line(x1, y1, x2, y2);if (!iDcStatus)return 0;Draw_Line(x1, y1, x2, y2, color, vb_start, iPitch);return 1;
}int Draw_Polygon2D(POLYGON2D_PTR poly, LONG* vb_strat, int iPitch)
{if (poly->state){for (int i = 0; i < poly->num_verts - 1; i++){Draw_Clip_Line(poly->vlist[i].x, poly->vlist[i].y, poly->vlist[i + 1].x, poly->vlist[i + 1].y, poly->color, vb_strat, iPitch);}Draw_Clip_Line(poly->vlist[poly->num_verts - 1].x, poly->vlist[poly->num_verts - 1].y, poly->vlist[0].x, poly->vlist[0].y, poly->color, vb_strat, iPitch);return 1;}return 0;
}int Rotate_Polygon2D(POLYGON2D_PTR poly, int theta)
{if (!poly)return 0;for (int curr_vert = 0; curr_vert < poly->num_verts; curr_vert++){float xr = poly->vlist[curr_vert].x * cos_look[theta] - poly->vlist[curr_vert].y * sin_look[theta];float yr = poly->vlist[curr_vert].x * sin_look[theta] + poly->vlist[curr_vert].y * cos_look[theta];poly->vlist[curr_vert].x = xr;poly->vlist[curr_vert].y = yr;}return 1;
}
下面是效果图：
