图形学基础概念(画布/位图/像素等)
这里写目录标题
- 1 介绍
- 2 基本概念
- 3 基础demo框架搭建
-
- 3.1 win32窗口原理
- 3.2 搭建demo框架
- 4 点/直线/雪花效果
1 介绍
看过那些书，走过那些路，依然过不好这一生；用过很多框架，依然成不了好的架构师。
本系列主要是介绍如果只给你一个点，让你实现一个3D的实现的过程以及会涉及到那些图形学知识。
2 基本概念
像素: RGBA四元素组成 (每个元素都是1byte，8个bit位)
含义：R红色 G绿色 B蓝色 A透明度
四元素计算出来就是像素点的颜色
画布：屏幕
位图：很多像素点组成
HDC：
3 基础demo框架搭建
3.1 win32窗口原理
1.编写WinMain函数
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR lpCmdLine,
_In_ int nCmdShow)
2.设计窗口类（WNDCLASS）
// 初始化全局字符串
LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadStringW(hInstance, IDC_WINDOWSPROJECT1, szWindowClass, MAX_LOADSTRING);
3.注册窗口类（RegisterClass）
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEXW wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WINDOWSPROJECT1));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassExW(&wcex);
}
4.创建窗口（CreatWindow）
hWnd = CreateWindowW(szWindowClass, szTitle, WS_POPUP,
CW_USEDEFAULT, 0, wWidth, wHeight, nullptr, nullptr, hInstance, nullptr);
5.显示并更新窗口
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
6.编写消息循环
while (GetMessage(&msg, nullptr, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
7.编写窗口过程函数
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// 分析菜单选择:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: 在此处添加使用 hdc 的任何绘图代码...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
3.2 搭建demo框架
//基础坐标
#pragma once
namespace GT
{
template<typename T>
struct tVec2
{
T x;
T y;
tVec2(T _x, T _y)
{
x = _x;
y = _y;
}
tVec2()
{
x = -1;
y = -1;
}
};
typedef tVec2<int> intV2;
typedef tVec2<float> floatV2;
typedef unsigned int uint;
typedef unsigned char byte;
}
//像素描述
#pragma once
#include //main函数
// WindowsProject1.cpp : 定义应用程序的入口点。
//
#include "framework.h"
#include "WindowsProject1.h"
#include "Canvas.h"
#define MAX_LOADSTRING 100
// 全局变量:
HINSTANCE hInst; // 当前实例
WCHAR szTitle[MAX_LOADSTRING]; // 标题栏文本
WCHAR szWindowClass[MAX_LOADSTRING]; // 主窗口类名
HWND hWnd;
int wWidth = 800;
int wHeight = 600;
HDC hDC = NULL;
HDC hMem = NULL;
GT::Canvas* _canvas = NULL;
// 此代码模块中包含的函数的前向声明:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM);
void Render();
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// 初始化全局字符串
LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadStringW(hInstance, IDC_WINDOWSPROJECT1, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// 执行应用程序初始化:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_WINDOWSPROJECT1));
//*******************创建绘图用的位图********************
void* buffer = 0;
hDC = GetDC(hWnd);
hMem = ::CreateCompatibleDC(hDC);
BITMAPINFO bmpInfo;
bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmpInfo.bmiHeader.biWidth = wWidth;
bmpInfo.bmiHeader.biHeight = wHeight;
bmpInfo.bmiHeader.biPlanes = 1;
bmpInfo.bmiHeader.biBitCount = 32;
bmpInfo.bmiHeader.biCompression = BI_RGB; //实际上存储的RGB
bmpInfo.bmiHeader.biSizeImage = 0;
bmpInfo.bmiHeader.biXPelsPerMeter = 0;
bmpInfo.bmiHeader.biYPelsPerMeter = 0;
bmpInfo.bmiHeader.biClrUsed = 0;
bmpInfo.bmiHeader.biClrImportant = 0;
HBITMAP hBmp = CreateDIBSection(hDC, &bmpInfo, DIB_RGB_COLORS, (void**)&buffer, 0, 0); //在这里创建Buffer内存
SelectObject(hMem, hBmp);
memset(buffer, 0, wWidth * wHeight * 4); //清空buffer为0
//*******************创建绘图用的位图********************
_canvas = new GT::Canvas(wWidth, wHeight, buffer);
MSG msg;
// 主消息循环:
while (GetMessage(&msg, nullptr, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
Render();
}
return (int) msg.wParam;
}
void Render()
{
_canvas->clear();
GT::RGBA _color(255, 0, 0, 0);
//点 为何是蓝色
_canvas->drawPoint(rand() % wWidth, rand() % wHeight, _color);
//直线
for (int x = 0; x < wWidth; x++)
{
_canvas->drawPoint(x, 100, _color);
}
//雪花
//for (int x = 0; x < wWidth; x++)
//{
// for (int y = 0; y < wHeight; y++)
// {
// GT::RGBA _color(rand() % 255, rand() % 255, rand() % 255);
// _canvas->drawPoint(x, y, _color);
// }
//
//}
//在这里画到设备上,hMem相当于缓冲区(将缓冲区buffer画到hdc上)
BitBlt(hDC, 0, 0, wWidth, wHeight, hMem, 0, 0, SRCCOPY);
}
//
// 函数: MyRegisterClass()
//
// 目标: 注册窗口类。
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEXW wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WINDOWSPROJECT1));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassExW(&wcex);
}
//
// 函数: InitInstance(HINSTANCE, int)
//
// 目标: 保存实例句柄并创建主窗口
//
// 注释:
//
// 在此函数中，我们在全局变量中保存实例句柄并
// 创建和显示主程序窗口。
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
hInst = hInstance; // 将实例句柄存储在全局变量中
hWnd = CreateWindowW(szWindowClass, szTitle, WS_POPUP,
CW_USEDEFAULT, 0, wWidth, wHeight, nullptr, nullptr, hInstance, nullptr);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
//
// 函数: WndProc(HWND, UINT, WPARAM, LPARAM)
//
// 目标: 处理主窗口的消息。
//
// WM_COMMAND - 处理应用程序菜单
// WM_PAINT - 绘制主窗口
// WM_DESTROY - 发送退出消息并返回
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// 分析菜单选择:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: 在此处添加使用 hdc 的任何绘图代码...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// “关于”框的消息处理程序。
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(lParam);
switch (message)
{
case WM_INITDIALOG:
return (INT_PTR)TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return (INT_PTR)TRUE;
}
break;
}
return (INT_PTR)FALSE;
}
4 点/直线/雪花效果
GT::RGBA _color(255, 0, 0, 0);
//点 为何是蓝色
_canvas->drawPoint(rand() % wWidth, rand() % wHeight, _color);
//直线
for (int x = 0; x < wWidth; x++)
{
_canvas->drawPoint(x, 100, _color);
}
//雪花
//for (int x = 0; x < wWidth; x++)
//{
// for (int y = 0; y < wHeight; y++)
// {
// GT::RGBA _color(rand() % 255, rand() % 255, rand() % 255);
// _canvas->drawPoint(x, y, _color);
// }
//
//}
线是很多点绘制而成