opengles之修改已有纹理glTexSubImage2D函数用法

时间:2023-02-09 11:23:47

opengles之修改已有纹理glTexSubImage2D函数用法

shader实现类:

#pragma once

#include <assert.h>

class    ShaderId
{
public:
	ShaderId()
	{
		_shaderId = -1;
	}
	int _shaderId;
};


/**
*   程序
*/
class   ProgramId
{
public:
	int         _programId;
	ShaderId    _vertex;
	ShaderId    _fragment;
public:
	ProgramId()
	{
		_programId = -1;
	}
public:
	/**
	*   加载函数
	*/
	bool    createProgram(const char* vertex, const char* fragment)
	{
		bool        error = false;
		do
		{
			if (vertex)
			{
				_vertex._shaderId = glCreateShader(GL_VERTEX_SHADER);
				glShaderSource(_vertex._shaderId, 1, &vertex, 0);
				glCompileShader(_vertex._shaderId);

				GLint   compileStatus;
				glGetShaderiv(_vertex._shaderId, GL_COMPILE_STATUS, &compileStatus);
				error = compileStatus == GL_FALSE;
				if (error)
				{
					GLchar messages[256];
					glGetShaderInfoLog(_vertex._shaderId, sizeof(messages), 0, messages);
					assert(messages && 0 != 0);
					break;
				}
			}
			if (fragment)
			{
				_fragment._shaderId = glCreateShader(GL_FRAGMENT_SHADER);
				glShaderSource(_fragment._shaderId, 1, &fragment, 0);
				glCompileShader(_fragment._shaderId);

				GLint   compileStatus;
				glGetShaderiv(_fragment._shaderId, GL_COMPILE_STATUS, &compileStatus);
				error = compileStatus == GL_FALSE;

				if (error)
				{
					GLchar messages[256];
					glGetShaderInfoLog(_fragment._shaderId, sizeof(messages), 0, messages);
					assert(messages && 0 != 0);
					break;
				}
			}
			_programId = glCreateProgram();

			if (_vertex._shaderId)
			{
				glAttachShader(_programId, _vertex._shaderId);
			}
			if (_fragment._shaderId)
			{
				glAttachShader(_programId, _fragment._shaderId);
			}

			glLinkProgram(_programId);

			GLint linkStatus;
			glGetProgramiv(_programId, GL_LINK_STATUS, &linkStatus);
			if (linkStatus == GL_FALSE)
			{
				GLchar messages[256];
				glGetProgramInfoLog(_programId, sizeof(messages), 0, messages);
				break;
			}
			glUseProgram(_programId);

		} while (false);

		if (error)
		{
			if (_fragment._shaderId)
			{
				glDeleteShader(_fragment._shaderId);
				_fragment._shaderId = 0;
			}
			if (_vertex._shaderId)
			{
				glDeleteShader(_vertex._shaderId);
				_vertex._shaderId = 0;
			}
			if (_programId)
			{
				glDeleteProgram(_programId);
				_programId = 0;
			}
		}
		return  true;
	}

	/**
	*   使用程序
	*/
	virtual void    begin()
	{
		glUseProgram(_programId);

	}
	/**
	*   使用完成
	*/
	virtual void    end()
	{
		glUseProgram(0);
	}
};



class   PROGRAM_P2_C4 :public ProgramId
{
public:
	typedef int attribute;
	typedef int uniform;
public:
	attribute   _position;
	uniform     _color;
	uniform     _MVP;
public:
	PROGRAM_P2_C4()
	{
		_position = -1;
		_color = -1;
		_MVP = -1;
	}
	~PROGRAM_P2_C4()
	{
	}

	/// 初始化函数
	virtual bool    initialize()
	{
		const char* vs =
		{
			"precision lowp float; "
			"uniform   mat4 _MVP;"
			"attribute vec2 _position;"

			"void main()"
			"{"
			"   vec4    pos =   vec4(_position,0,1);"
			"   gl_Position =   _MVP * pos;"
			"}"
		};
		const char* ps =
		{
			"precision  lowp float; "
			"uniform    vec4 _color;"
			"void main()"
			"{"
			"   gl_FragColor   =   _color;"
			"}"
		};

		bool    res = createProgram(vs, ps);
		if (res)
		{
			_position = glGetAttribLocation(_programId, "_position");
			_color = glGetUniformLocation(_programId, "_color");
			_MVP = glGetUniformLocation(_programId, "_MVP");
		}
		return  res;
	}

	/**
	*   使用程序
	*/
	virtual void    begin()
	{
		glUseProgram(_programId);
		glEnableVertexAttribArray(_position);

	}
	/**
	*   使用完成
	*/
	virtual void    end()
	{
		glDisableVertexAttribArray(_position);
		glUseProgram(0);
	}
};
class   PROGRAM_P2_AC4 :public ProgramId
{
public:
	typedef int attribute;
	typedef int uniform;
public:
	attribute   _position;
	attribute   _color;
	uniform     _MVP;
public:
	PROGRAM_P2_AC4()
	{
		_position = -1;
		_color = -1;
		_MVP = -1;
	}
	~PROGRAM_P2_AC4()
	{
	}

	/// 初始化函数
	virtual bool    initialize()
	{
		const char* vs =
		{
			"precision lowp float; "
			"uniform   mat4 _MVP;"
			"attribute vec2 _position;"
			"attribute vec4 _color;"
			"varying   vec4 _outColor;"

			"void main()"
			"{"
			"   vec4    pos =   vec4(_position,0,1);"
			"   _outColor   =   _color;"
			"   gl_Position =   _MVP * pos;"
			"}"
		};
		const char* ps =
		{
			"precision  lowp float; "
			"varying   vec4 _outColor;"
			"void main()"
			"{"
			"   gl_FragColor   =   _outColor;"
			"}"
		};

		bool    res = createProgram(vs, ps);
		if (res)
		{
			_position = glGetAttribLocation(_programId, "_position");
			_color = glGetAttribLocation(_programId, "_color");
			_MVP = glGetUniformLocation(_programId, "_MVP");
		}
		return  res;
	}

	/**
	*   使用程序
	*/
	virtual void    begin()
	{
		glUseProgram(_programId);
		glEnableVertexAttribArray(_position);
		glEnableVertexAttribArray(_color);

	}
	/**
	*   使用完成
	*/
	virtual void    end()
	{
		glDisableVertexAttribArray(_position);
		glDisableVertexAttribArray(_color);
		glUseProgram(0);
	}
};



class   PROGRAM_P2_UV_AC4 :public ProgramId
{
public:
	typedef int attribute;
	typedef int uniform;
public:
	attribute   _position;
	attribute   _color;
	attribute   _uv;
	uniform     _MVP;
	uniform     _texture;
public:
	PROGRAM_P2_UV_AC4()
	{
		_position = -1;
		_color = -1;
		_uv = -1;
		_texture = -1;
		_MVP = -1;
	}
	~PROGRAM_P2_UV_AC4()
	{
	}

	/// 初始化函数
	virtual bool    initialize()
	{
		const char* vs =
		{
			"precision lowp float; "
			"uniform   mat4 _MVP;"
			"attribute vec2 _position;"
			"attribute vec2 _uv;"
			"attribute vec4 _color;"
			"varying   vec4 _outColor;"
			"varying   vec2 _outUV;"

			"void main()"
			"{"
			"   vec4    pos =   vec4(_position,0,1);"
			"   _outColor   =   _color;"
			"   _outUV      =   _uv;"
			"   gl_Position =   _MVP * pos;"
			"}"
		};
		const char* ps =
		{
			"precision  lowp float; "
			"uniform   sampler2D _texture;\n"
			"varying   vec4      _outColor;\n"
			"varying   vec2      _outUV;\n"
			"void main()"
			"{"
			"   vec4    tColor  =   texture2D(_texture,_outUV);\n"
			"   gl_FragColor    =   tColor * _outColor;\n"
			"}"
		};

		bool    res = createProgram(vs, ps);
		if (res)
		{
			_position = glGetAttribLocation(_programId, "_position");
			_color = glGetAttribLocation(_programId, "_color");
			_uv = glGetAttribLocation(_programId, "_uv");
			_texture = glGetUniformLocation(_programId, "_texture");
			_MVP = glGetUniformLocation(_programId, "_MVP");
		}
		return  res;
	}

	/**
	*   使用程序
	*/
	virtual void    begin()
	{
		glUseProgram(_programId);
		glEnableVertexAttribArray(_position);
		glEnableVertexAttribArray(_uv);
		glEnableVertexAttribArray(_color);

	}
	/**
	*   使用完成
	*/
	virtual void    end()
	{
		glDisableVertexAttribArray(_position);
		glDisableVertexAttribArray(_uv);
		glDisableVertexAttribArray(_color);
		glUseProgram(0);
	}
};

窗口实现类:

#pragma once

#include <Windows.h>
#include <tchar.h>
#include <math.h>

#include <EGL/egl.h>
#include <gles2/gl2.h>

#include "freeImage/FreeImage.h"

#include "CELLMath.hpp"
#include "CELLShader.hpp"

namespace   CELL
{
	class   CELLWinApp
	{
	public:
		//! 实例句柄
		HINSTANCE   _hInstance;
		//! 窗口句柄
		HWND        _hWnd;
		//! 窗口的高度
		int         _width;
		//! 窗口的宽度
		int         _height;
		/// for gles2.0
		EGLConfig   _config;
		EGLSurface  _surface;
		EGLContext  _context;
		EGLDisplay  _display;
		//! 增加shader
		PROGRAM_P2_UV_AC4  _shader;
		unsigned        _textureId;
	public:
		CELLWinApp(HINSTANCE hInstance)
			:_hInstance(hInstance)
		{
			WNDCLASSEX  winClass;
			winClass.lpszClassName = _T("CELLWinApp");
			winClass.cbSize = sizeof(winClass);
			winClass.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
			winClass.lpfnWndProc = wndProc;
			winClass.hInstance = hInstance;
			winClass.hIcon = 0;
			winClass.hIconSm = 0;
			winClass.hCursor = LoadCursor(hInstance, IDC_ARROW);
			winClass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
			winClass.lpszMenuName = NULL;
			winClass.cbClsExtra = 0;
			winClass.cbWndExtra = 0;
			RegisterClassEx(&winClass);

			_textureId = 0;
		}
		virtual ~CELLWinApp()
		{
			UnregisterClass(_T("CELLWinApp"), _hInstance);
		}

		/**
		*   初始化 OpenGLES2.0
		*/
		bool    initOpenGLES20()
		{
			const EGLint attribs[] =
			{
				EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
				EGL_BLUE_SIZE, 8,
				EGL_GREEN_SIZE, 8,
				EGL_RED_SIZE, 8,
				EGL_DEPTH_SIZE, 24,
				EGL_NONE
			};
			EGLint 	format(0);
			EGLint	numConfigs(0);
			EGLint  major;
			EGLint  minor;

			//! 1
			_display = eglGetDisplay(EGL_DEFAULT_DISPLAY);

			//! 2init
			eglInitialize(_display, &major, &minor);

			//! 3
			eglChooseConfig(_display, attribs, &_config, 1, &numConfigs);

			eglGetConfigAttrib(_display, _config, EGL_NATIVE_VISUAL_ID, &format);
			//! 4 
			_surface = eglCreateWindowSurface(_display, _config, _hWnd, NULL);

			//! 5
			EGLint attr[] = { EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE, EGL_NONE };
			_context = eglCreateContext(_display, _config, 0, attr);
			//! 6
			if (eglMakeCurrent(_display, _surface, _surface, _context) == EGL_FALSE)
			{
				return false;
			}

			eglQuerySurface(_display, _surface, EGL_WIDTH, &_width);
			eglQuerySurface(_display, _surface, EGL_HEIGHT, &_height);

			return  true;

		}
		/**
		*   销毁OpenGLES2.0
		*/
		void    destroyOpenGLES20()
		{
			if (_display != EGL_NO_DISPLAY)
			{
				eglMakeCurrent(_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
				if (_context != EGL_NO_CONTEXT)
				{
					eglDestroyContext(_display, _context);
				}
				if (_surface != EGL_NO_SURFACE)
				{
					eglDestroySurface(_display, _surface);
				}
				eglTerminate(_display);
			}
			_display = EGL_NO_DISPLAY;
			_context = EGL_NO_CONTEXT;
			_surface = EGL_NO_SURFACE;
		}

		virtual unsigned    loadTexture(const char* fileName)
		{
			unsigned    textureId = 0;
			//1 获取图片格式
			FREE_IMAGE_FORMAT fifmt = FreeImage_GetFileType(fileName, 0);

			//2 加载图片
			FIBITMAP    *dib = FreeImage_Load(fifmt, fileName, 0);

			//3 转化为rgb 24色
			dib = FreeImage_ConvertTo24Bits(dib);



			//4 获取数据指针
			BYTE    *pixels = (BYTE*)FreeImage_GetBits(dib);

			int     width = FreeImage_GetWidth(dib);
			int     height = FreeImage_GetHeight(dib);

			for (size_t i = 0; i < width * height * 3; i += 3)
			{
				BYTE temp = pixels[i];
				pixels[i] = pixels[i + 2];
				pixels[i + 2] = temp;
			}

			/**
			*   产生一个纹理Id,可以认为是纹理句柄,后面的操作将书用这个纹理id
			*/
			glGenTextures(1, &textureId);

			/**
			*   使用这个纹理id,或者叫绑定(关联)
			*/
			glBindTexture(GL_TEXTURE_2D, textureId);
			/**
			*   指定纹理的放大,缩小滤波,使用线性方式,即当图片放大的时候插值方式
			*/
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

			/*
			*当纹理坐标超出[0,0]到[1,1]的范围时纹理坐标的处理由wrap参数指定,

			*1--GL_REPEAT:坐标的整数部分被忽略,重复纹理,这是OpenGL纹理默认的处理方式.
			*2--GL_MIRRORED_REPEAT: 纹理也会被重复,但是当纹理坐标的整数部分是奇数时会使用镜像重复。
			*3--GL_CLAMP_TO_EDGE: 坐标会被截断到[0,1]之间。结果是坐标值大的被截断到纹理的边缘部分,形成了一个拉伸的边缘(stretched edge pattern)。
			*/
			
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);

			/**
			*   将图片的rgb数据上传给opengl.
			*/
			glTexImage2D(
				GL_TEXTURE_2D,      //! 指定是二维图片
				0,                  //! 指定为第一级别,纹理可以做mipmap,即lod,离近的就采用级别大的,远则使用较小的纹理
				GL_RGB,             //! 纹理的使用的存储格式
				width,              //! 宽度,老一点的显卡,不支持不规则的纹理,即宽度和高度不是2^n。
				height,             //! 宽度,老一点的显卡,不支持不规则的纹理,即宽度和高度不是2^n。
				0,                  //! 是否的边
				GL_RGB,             //! 数据的格式,bmp中,windows,操作系统中存储的数据是bgr格式
				GL_UNSIGNED_BYTE,   //! 数据是8bit数据
				pixels
				);

			char    subData[100 * 100 * 3];
			memset(subData, 255, sizeof(subData));
			/**
			功能:提供修改图像的功能,因为修改一个纹理比重新创建一个纹理开销小很多,对于一些视频捕捉程序可以先将视频图像存储在更大的初始图像中
			(图像大小要是2^n,opengl2.0后没有这个限制),创建一个渲染用的纹理,然后反复调用glTexSubImage2D(修改的图像区域不用是2^n)函数从视频图像区域读取到渲染
			纹理图像中,渲染用的纹理图像只需要创建一次即可。
			函数原型 glTexSubImage2D (GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const GLvoid *pixels)
			target:必须是glCopyTexImage2D中对应的target可用值
			level:mipmap等级
			xoffset,yoffset是要修改的图像左上角偏移,width,height是要修改的图像宽高像素修改的范围在原图之外并不受影响
			format,type:表示图像的数据格式和类型
			pixels:子图像的纹理数据
			*/
			glTexSubImage2D(GL_TEXTURE_2D, 0, 100, 100, 100, 100, GL_RGB, GL_UNSIGNED_BYTE, subData);


			/**
			*   释放内存
			*/
			FreeImage_Unload(dib);

			return  textureId;
		}



	protected:
		static  LRESULT CALLBACK wndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
		{

			CELLWinApp*  pThis = (CELLWinApp*)GetWindowLong(hWnd, GWL_USERDATA);
			if (pThis)
			{
				return  pThis->onEvent(hWnd, msg, wParam, lParam);
			}
			if (WM_CREATE == msg)
			{
				CREATESTRUCT*   pCreate = (CREATESTRUCT*)lParam;
				SetWindowLong(hWnd, GWL_USERDATA, (DWORD_PTR)pCreate->lpCreateParams);
			}
			return  DefWindowProc(hWnd, msg, wParam, lParam);
		}
	public:
		/**
		*   事件函数
		*/
		virtual LRESULT onEvent(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
		{
			switch (msg)
			{
			case WM_CLOSE:
			case WM_DESTROY:
			{
				::PostQuitMessage(0);
			}
				break;
			case WM_MOUSEMOVE:
				break;
			default:
				return  DefWindowProc(hWnd, msg, wParam, lParam);
			}
			return  S_OK;

		}

		virtual void    render()
		{

			struct  Vertex
			{
				CELL::float2    pos;
				CELL::float2    uv;
				CELL::Rgba4Byte color;
			};
			//! 清空缓冲区
			glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
			//! 视口,在Windows窗口指定的位置和大小上绘制OpenGL内容
			glViewport(0, 0, _width, _height);

			//! 创建一个投影矩阵

			glBindTexture(GL_TEXTURE_2D, _textureId);

			CELL::matrix4   screenProj = CELL::ortho<float>(0, float(_width), float(_height), 0, -100.0f, 100);
			_shader.begin();
			{
				float   x = 100;
				float   y = 100;
				float   w = 400;
				float   h = 400;
				float   rt = 2;
				Vertex  vertex[] =
				{
					CELL::float2(x, y), CELL::float2(0, 0), CELL::Rgba4Byte(255, 255, 255, 255),
					CELL::float2(x + w, y), CELL::float2(rt, 0), CELL::Rgba4Byte(255, 255, 255, 255),
					CELL::float2(x, y + h), CELL::float2(0, rt), CELL::Rgba4Byte(255, 255, 255, 255),
					CELL::float2(x + w, y + h), CELL::float2(rt, rt), CELL::Rgba4Byte(255, 255, 255, 255),
				};

				CELL::matrix4       matMVP = screenProj;



				glUniformMatrix4fv(_shader._MVP, 1, false, matMVP.data());
				glUniform1i(_shader._texture, 0);
				glVertexAttribPointer(_shader._position, 2, GL_FLOAT, false, sizeof(Vertex), vertex);
				glVertexAttribPointer(_shader._uv, 2, GL_FLOAT, false, sizeof(Vertex), &vertex[0].uv);
				glVertexAttribPointer(_shader._color, 4, GL_UNSIGNED_BYTE, true, sizeof(Vertex), &vertex[0].color);
				glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

			}
			_shader.end();

		}
		/**
		*   主函数
		*/
		int     main(int width, int height)
		{
			_hWnd = CreateWindowEx(NULL,
				_T("CELLWinApp"),
				_T("CELLWinApp"),
				WS_OVERLAPPEDWINDOW,
				CW_USEDEFAULT,
				CW_USEDEFAULT,
				width,
				height,
				NULL,
				NULL,
				_hInstance,
				this
				);

			if (_hWnd == 0)
			{
				return  -1;
			}
			UpdateWindow(_hWnd);

			ShowWindow(_hWnd, SW_SHOW);

			if (!initOpenGLES20())
			{
				return  false;
			}
			_shader.initialize();

			_textureId = loadTexture("Debug/data/image/5.jpg");
			MSG msg = { 0 };
			while (msg.message != WM_QUIT)
			{
				if (msg.message == WM_DESTROY ||
					msg.message == WM_CLOSE)
				{
					break;
				}
				/**
				*   有消息,处理消息,无消息,则进行渲染绘制
				*/
				if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
				{
					TranslateMessage(&msg);
					DispatchMessage(&msg);
				}
				else
				{
					render();
					eglSwapBuffers(_display, _surface);
				}
			}
			/**
			*   销毁OpenGLES20
			*/
			destroyOpenGLES20();

			return  0;
		}
	};
}

程序入口:

#include "CELLWinApp.hpp"



int APIENTRY _tWinMain(HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPTSTR    lpCmdLine,
	int       nCmdShow)
{
	UNREFERENCED_PARAMETER(hPrevInstance);
	UNREFERENCED_PARAMETER(hInstance);
	UNREFERENCED_PARAMETER(lpCmdLine);
	UNREFERENCED_PARAMETER(nCmdShow);


	CELL::CELLWinApp  app(hInstance);
	app.main(800, 600);

	return 0;
}


完整项目下载地址:http://download.csdn.net/detail/hb707934728/9837754