opengles中使用vbo(顶点缓冲区)
为什么要使用VBO:
如果不使用vbo，要绘制物体的顶点信息需要从内存传递到显存，当绘制的模型比较复杂时，频繁的在内存和显存中做数据传递会降低效率。因此使用VBO，可以先把一部分顶点数据缓存起来，绘制的时候直接从缓存中获取，大大降低内存和显存之间数据拷贝的开销,总而言之是为了提高绘制效率。
如何使用vbo：
//申明顶点数据结构
struct Vertex
{
float x, y, z;
float u, v;
float r, g, b, a;
};
Vertex vertexs[] =
{
{ -1.0f, -1.0f, -8.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ 1.0f, -1.0f, -8.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ 1.0f, 1.0f, -8.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ -1.0f, -1.0f, -8.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ 1.0f, 1.0f, -8.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ -1.0f, 1.0f, -8.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
};
/*
为什么要使用vbo (顶点缓冲区):如果不使用vbo，要绘制物体的顶点信息需要从内存传递到显存，
当绘制的模型比较复杂时，频繁的在内存和显存中做数据传递会降低效率。
因此使用VBO，可以先把一部分顶点数据缓存起来，绘制的时候直接从缓存中获取，
大大降低内存和显存之间数据拷贝的开销。
*/
glGenBuffers(1,&_vbo);//声明一个vbo
glBindBuffer(GL_ARRAY_BUFFER,_vbo);//指定buffer类型为顶点buffer
glBufferData(GL_ARRAY_BUFFER,sizeof(vertexs),vertexs,GL_STATIC_DRAW);//将顶点数据拷贝到显存
glBindBuffer(GL_ARRAY_BUFFER, 0);//禁用缓存
//使用vbo绘制
glBindTexture(GL_TEXTURE_2D, _texGrass);
glBindBuffer(GL_ARRAY_BUFFER, _vbo);
glUniformMatrix4fv(_shader._MVP, 1, false, MVP1.data());
glVertexAttribPointer(_shader._positionAttr, 3, GL_FLOAT, false, sizeof(Vertex), (void*)0);//sizeof(Vertex) 偏移量:(void*)0 起始地址
glVertexAttribPointer(_shader._uvAttr, 2, GL_FLOAT, false, sizeof(Vertex), (void*)12);// (void*)12 起始地址 每个float4个字节 每个顶点有3个float(x,y,z)
glVertexAttribPointer(_shader._colorAttr, 4, GL_FLOAT, false, sizeof(Vertex), (void*)20);//12+8 三个位置坐标占12byte 两个纹理坐标占8byte 故颜色坐标的偏移量是20
glDrawArrays(GL_TRIANGLES, 0, 6);
//这步是必须的
glBindBuffer(GL_ARRAY_BUFFER, 0);//禁用缓存shader实现类:
#pragma once
#include
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;
//! 第二阶段文理
uniform _texture1;
uniform _uvAnim;
public:
PROGRAM_P2_UV_AC4()
{
_position = -1;
_color = -1;
_uv = -1;
_texture = -1;
_texture1 = -1;
_uvAnim = -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"
"uniform sampler2D _texture1;\n"
"uniform float _uvAnim;\n"
"varying vec4 _outColor;\n"
"varying vec2 _outUV;\n"
"void main()"
"{"
" vec4 tColor0 = texture2D(_texture,_outUV);\n"
" vec2 newUV = vec2(_uvAnim + _outUV.x,_outUV.y);"
" vec4 tColor1 = texture2D(_texture1,newUV);\n"
" gl_FragColor = tColor0 * tColor1;\n"
"}"
};
bool res = createProgram(vs, ps);
if (res)
{
_position = glGetAttribLocation(_programId, "_position");
_color = glGetAttribLocation(_programId, "_color");
_uv = glGetAttribLocation(_programId, "_uv");
_texture = glGetUniformLocation(_programId, "_texture");
_texture1 = glGetUniformLocation(_programId, "_texture1");
_MVP = glGetUniformLocation(_programId, "_MVP");
_uvAnim = glGetUniformLocation(_programId, "_uvAnim");
}
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);
}
};
class PROGRAM_P3_UV :public ProgramId
{
public:
typedef int attribute;
typedef int uniform;
public:
attribute _position;
attribute _uv;
uniform _MVP;
uniform _texture;
public:
PROGRAM_P3_UV()
{
_position = -1;
_uv = -1;
_texture = -1;
_MVP = -1;
}
~PROGRAM_P3_UV()
{
}
/// 初始化函数
virtual bool initialize()
{
const char* vs =
{
"precision lowp float; "
"uniform mat4 _MVP;"
"attribute vec2 _position;"
"attribute vec2 _uv;"
"varying vec2 _outUV;"
"void main()"
"{"
" vec4 pos = vec4(_position,0,1);"
" _outUV = _uv;"
" gl_Position = _MVP * pos;"
"}"
};
const char* ps =
{
"precision lowp float; "
"uniform sampler2D _texture;\n"
"varying vec2 _outUV;\n"
"void main()"
"{"
" vec4 tColor0 = texture2D(_texture,_outUV);\n"
" gl_FragColor = tColor0;\n"
"}"
};
bool res = createProgram(vs, ps);
if (res)
{
_position = glGetAttribLocation(_programId, "_position");
_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);
}
/**
* 使用完成
*/
virtual void end()
{
glDisableVertexAttribArray(_position);
glDisableVertexAttribArray(_uv);
glUseProgram(0);
}
};
class PROGRAM_P2_T2_C3 :public ProgramId
{
public:
typedef int location;
public:
location _positionAttr;
location _colorAttr;
location _uvAttr;
location _MVP;
location _texture;
public:
PROGRAM_P2_T2_C3()
{
_positionAttr = -1;
_colorAttr = -1;
_uvAttr = -1;
_MVP = -1;
}
~PROGRAM_P2_T2_C3()
{
}
/// 初始化函数
virtual bool initialize()
{
const char* vs =
{
"uniform mat4 _MVP;"
"attribute vec3 _position;"
"attribute vec4 _color;"
"attribute vec2 _uv;"
"varying vec4 _outColor;"
"varying vec2 _outUV;"
"void main()"
"{"
" vec4 pos = vec4(_position.x,_position.y,_position.z,1);"
" gl_Position = _MVP * pos;"
" _outColor = _color;"
" _outUV = _uv;"
"}"
};
const char* ps =
{
"precision lowp float; "
"uniform sampler2D _texture;\n"
"varying vec4 _outColor;\n"
"varying vec2 _outUV;"
"void main()"
"{"
" vec4 color = texture2D(_texture,_outUV);"
" if(color.a < 0.2)"
" discard;"
" gl_FragColor = color * _outColor;"
"}"
};
bool res = createProgram(vs, ps);
if (res)
{
_positionAttr = glGetAttribLocation(_programId, "_position");
_colorAttr = glGetAttribLocation(_programId, "_color");
_uvAttr = glGetAttribLocation(_programId, "_uv");
_MVP = glGetUniformLocation(_programId, "_MVP");
_texture = glGetUniformLocation(_programId, "_texture");
}
return res;
}
/**
* 使用程序
*/
virtual void begin()
{
glUseProgram(_programId);
glEnableVertexAttribArray(_positionAttr);
glEnableVertexAttribArray(_uvAttr);
glEnableVertexAttribArray(_colorAttr);
}
/**
* 使用完成
*/
virtual void end()
{
glDisableVertexAttribArray(_positionAttr);
glDisableVertexAttribArray(_uvAttr);
glDisableVertexAttribArray(_colorAttr);
glUseProgram(0);
}
};
窗口实现类：
#pragma once
#include
#include
#include
#include
#include
#include "freeImage/FreeImage.h"
#include "CELLMath.hpp"
#include "CELLShader.hpp"
namespace CELL
{
class FirstCameraInfor
{
public:
FirstCameraInfor()
{
_moveSpeed = 5;
_eye = CELL::float3(0.0f, 10.0f, 0.0f);
_look = CELL::float3(0.5f, -0.4f, -0.5f);
_up = CELL::float3(0, 1, 0);
_right = CELL::float3(1, 0, 0);
}
CELL::float3 _eye;
CELL::float3 _look;
CELL::float3 _up;
CELL::float3 _right;
float _moveSpeed;
public:
void updateCamera(float fElapsed)
{
CELL::float3 tmpLook = _look;
CELL::float3 dir = _look - _eye;
dir = normalize(dir);
//! 这里调用windows函数获取键盘的状态
unsigned char keys[256];
GetKeyboardState(keys);
if (keys[VK_UP] & 0x80)
{
_eye -= dir*-_moveSpeed * fElapsed;
_look -= dir*-_moveSpeed * fElapsed;
}
if (keys[VK_DOWN] & 0x80)
{
_eye += (dir*-_moveSpeed) * fElapsed;
_look += (dir*-_moveSpeed) * fElapsed;
}
if (keys[VK_LEFT] & 0x80)
{
_eye -= (_right*_moveSpeed) * fElapsed;
_look -= (_right*_moveSpeed) * fElapsed;
}
if (keys[VK_RIGHT] & 0x80)
{
_eye += (_right*_moveSpeed) * fElapsed;
_look += (_right*_moveSpeed) * fElapsed;
}
}
};
class CELLWinApp
{
public:
//申明顶点数据结构
struct Vertex
{
float x, y, z;
float u, v;
float r, g, b, a;
};
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_T2_C3 _shader;
unsigned _textureId;
unsigned _texDynamic;
unsigned _texGrass;
FirstCameraInfor _camera;
unsigned _vbo;
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 createTexture(int width, int height)
{
unsigned textureId;
glGenTextures(1, &textureId);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexImage2D(
GL_TEXTURE_2D
, 0
, GL_RGB
, width
, height
, 0
, GL_RGB
, GL_UNSIGNED_BYTE
, 0);
return textureId;
}
virtual unsigned buildMipMap(char* fileNames[], int size)
{
unsigned textureId = 0;
/**
* 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_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
for (int i = 0; i < size; ++i)
{
//1 获取图片格式
FREE_IMAGE_FORMAT fifmt = FreeImage_GetFileType(fileNames[i], 0);
//2 加载图片
FIBITMAP *dib = FreeImage_Load(fifmt, fileNames[i], 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 (int x = 0; x < width * height * 3; x += 3)
{
BYTE temp = pixels[x];
pixels[x] = pixels[x + 2];
pixels[x + 2] = temp;
}
/**
* 将图片的rgb数据上传给opengl.
*/
glTexImage2D(
GL_TEXTURE_2D, //! 指定是二维图片
i, //! 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
);
FreeImage_Unload(dib);
}
return textureId;
}
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);
int fmt = GL_RGB;
//4 获取数据指针
BYTE *pixels = (BYTE*)FreeImage_GetBits(dib);
int width = FreeImage_GetWidth(dib);
int height = FreeImage_GetHeight(dib);
if (fifmt == FIF_PNG)
{
dib = FreeImage_ConvertTo32Bits(dib);
fmt = GL_RGBA;
for (int i = 0; i < width * height * 4; i += 4)
{
BYTE temp = pixels[i];
pixels[i] = pixels[i + 2];
pixels[i + 2] = temp;
}
}
else
{
//3 转化为rgb 24色
dib = FreeImage_ConvertTo24Bits(dib);
for (int 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_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
/**
* 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
fmt, //! 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
fmt, //! 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
);
/**
* 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()
{
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
glViewport(0, 0, _width, _width);
_camera.updateCamera(0.016f);
CELL::matrix4 matView = CELL::lookAt(_camera._eye, _camera._look, _camera._up);
float x = 0;
float y = 0;
float w = 200;
float h = 200;
Vertex vertex[] =
{
{ x, y, 0, 0, 1, 1.0f, 1.0f, 1.0f, 1.0f },
{ x + w, y, 0, 1, 1, 1.0f, 1.0f, 1.0f, 1.0f },
{ x, y + h, 0, 0, 0, 1.0f, 1.0f, 1.0f, 1.0f },
{ x + w, y + h, 0, 1, 0, 1.0f, 1.0f, 1.0f, 1.0f },
};
float gSize = 100;
float gPos = -5;
float rept = 100;
Vertex grounds[] =
{
{ -gSize, gPos, -gSize, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ gSize, gPos, -gSize, rept, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ gSize, gPos, gSize, rept, rept, 1.0f, 1.0f, 1.0f, 1.0f },
{ -gSize, gPos, -gSize, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ gSize, gPos, gSize, rept, rept, 1.0f, 1.0f, 1.0f, 1.0f },
{ -gSize, gPos, gSize, 0.0f, rept, 1.0f, 1.0f, 1.0f, 1.0f },
};
_shader.begin();
{
CELL::matrix4 matWorld(1);
CELL::matrix4 matProj = CELL::perspective(45.0f, (GLfloat)_width / (GLfloat)_height, 0.1f, 100.0f);
CELL::matrix4 MVP = matProj * matView * matWorld;
glUniform1i(_shader._texture, 0);
//! 绘制地面
glBindTexture(GL_TEXTURE_2D, _textureId);
glUniformMatrix4fv(_shader._MVP, 1, false, MVP.data());
glVertexAttribPointer(_shader._positionAttr, 3, GL_FLOAT, false, sizeof(Vertex), &grounds[0].x);
glVertexAttribPointer(_shader._uvAttr, 2, GL_FLOAT, false, sizeof(Vertex), &grounds[0].u);
glVertexAttribPointer(_shader._colorAttr, 4, GL_FLOAT, false, sizeof(Vertex), &grounds[0].r);
glDrawArrays(GL_TRIANGLES, 0, sizeof(grounds) / sizeof(grounds[0]));
CELL::matrix4 matRot;
static float angle = 0;
matRot.translate(0, 0, -1);
angle += 1;
CELL::matrix4 MVP1 = matProj * matView * matRot;
//使用vbo绘制
glBindTexture(GL_TEXTURE_2D, _texGrass);
glBindBuffer(GL_ARRAY_BUFFER, _vbo);
glUniformMatrix4fv(_shader._MVP, 1, false, MVP1.data());
glVertexAttribPointer(_shader._positionAttr, 3, GL_FLOAT, false, sizeof(Vertex), (void*)0);//sizeof(Vertex) 偏移量:(void*)0 起始地址
glVertexAttribPointer(_shader._uvAttr, 2, GL_FLOAT, false, sizeof(Vertex), (void*)12);// (void*)12 起始地址 每个float4个字节 每个顶点有3个float(x,y,z)
glVertexAttribPointer(_shader._colorAttr, 4, GL_FLOAT, false, sizeof(Vertex), (void*)20);//12+8 三个位置坐标占12byte 两个纹理坐标占8byte 故颜色坐标的偏移量是20
glDrawArrays(GL_TRIANGLES, 0, 6);
//这步是必须的
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindTexture(GL_TEXTURE_2D, _texDynamic);
glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, _width, _height);
CELL::matrix4 screenProj = CELL::ortho(0, float(_width), float(_height), 0, -100.0f, 100);
glUniformMatrix4fv(_shader._MVP, 1, false, screenProj.data());
glVertexAttribPointer(_shader._positionAttr, 3, GL_FLOAT, false, sizeof(Vertex), &vertex[0].x);
glVertexAttribPointer(_shader._uvAttr, 2, GL_FLOAT, false, sizeof(Vertex), &vertex[0].u);
glVertexAttribPointer(_shader._colorAttr, 4, GL_FLOAT, false, sizeof(Vertex), &vertex[0].r);
glDrawArrays(GL_TRIANGLE_STRIP, 0, sizeof(vertex) / sizeof(vertex[0]));
}
_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;
}
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_DEPTH_TEST);
//Vertex vertexs[] =
//{
// { -1.0f, -1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
// { 1.0f, -1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
// { 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
// { -1.0f, -1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
// { 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
// { -1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
//};
Vertex vertexs[] =
{
{ -1.0f, -1.0f, -8.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ 1.0f, -1.0f, -8.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ 1.0f, 1.0f, -8.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ -1.0f, -1.0f, -8.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ 1.0f, 1.0f, -8.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
{ -1.0f, 1.0f, -8.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
};
/*
为什么要使用vbo (顶点缓冲区):如果不使用vbo，要绘制物体的顶点信息需要从内存传递到显存，
当绘制的模型比较复杂时，频繁的在内存和显存中做数据传递会降低效率。
因此使用VBO，可以先把一部分顶点数据缓存起来，绘制的时候直接从缓存中获取，
大大降低内存和显存之间数据拷贝的开销。
*/
glGenBuffers(1,&_vbo);//声明一个vbo
glBindBuffer(GL_ARRAY_BUFFER,_vbo);//指定buffer类型为顶点buffer
glBufferData(GL_ARRAY_BUFFER,sizeof(vertexs),vertexs,GL_STATIC_DRAW);//将顶点数据拷贝到显存
glBindBuffer(GL_ARRAY_BUFFER, 0);
_shader.initialize();
char* szName[] =
{
"Debug/data/image/tex33X32.bmp",
"Debug/data/image/tex16X16.bmp",
"Debug/data/image/tex8x8.bmp",
"Debug/data/image/tex4x4.bmp",
"Debug/data/image/tex2X2.bmp",
"Debug/data/image/tex1x1.bmp",
};
_textureId = buildMipMap(szName, 6);
_texGrass = loadTexture("Debug/data/image/grass.png");
_texDynamic = createTexture(_width, _height);
_camera._eye = CELL::float3(1, 1, 5);
_camera._look = CELL::float3(0.5f, -0.4f, -5.5f);
_camera._up = CELL::float3(0.0f, 1.0f, 0.0f);
_camera._right = CELL::float3(1.0f, 0.0f, 0.0f);
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;
}
完整代码下载地址：http://download.csdn.net/detail/hb707934728/9843449