绘制一个隧道
定义绘制批次类
GLShaderManager shaderManager; //着色器管理器
GLMatrixStack modelViewMatrix; //模型视图矩阵
GLMatrixStack projectionMatrix; //投影矩阵
GLFrustum viewFrustum; //视景体
GLGeometryTransform transformPipeline; //几何变换管线
//4个批次容器类
GLBatch floorBatch;//地面
GLBatch ceilingBatch;//天花板
GLBatch leftWallBatch;//左墙面
GLBatch rightWallBatch;//右墙面
//深度初始值，-65。
GLfloat viewZ = -65.0f;
// 纹理标识符号
#define TEXTURE_BRICK 0 //墙面
#define TEXTURE_FLOOR 1 //地板
#define TEXTURE_CEILING 2 //纹理天花板
#define TEXTURE_COUNT 3 //纹理个数
GLuint textures[TEXTURE_COUNT];//纹理标记数组
//文件tag名字数组
const char *szTextureFiles[TEXTURE_COUNT] = { "brick.tga", "floor.tga", "ceiling.tga" };
初始化
floor.png
ceiling.png
leftWall.png
rightWall.png
//在这个函数里能够在渲染环境中进行任何需要的初始化，它这里的设置并初始化纹理对象
void SetupRC()
{
GLbyte *pBytes;
GLint iWidth,iHeight,iComponents;
GLenum eFormat;
GLint iLoop;
//背景
glClearColor(0.0f, 0.0f, 0.0f,1.0f);
shaderManager.InitializeStockShaders();
//1.加载纹理
/*
glGenTextures (GLsizei n, GLuint *textures)
参数1:n,纹理数量
参数2:textures,纹理对象标识数组
*/
glGenTextures(TEXTURE_COUNT, textures);
for (iLoop =0; iLoop < TEXTURE_COUNT; iLoop++) {
//2.绑定纹理
/*
glBindTexture (GLenum target, GLuint texture);
参数1:target,使用的纹理类型GL_TEXTURE_1D\GL_TEXTURE_2D\GL_TEXTURE_3D
参数2:texture,纹理的标记
*/
glBindTexture(GL_TEXTURE_2D, textures[iLoop]);
//3.加载tga文件
/*
GLbyte *gltReadTGABits(const char *szFileName, GLint *iWidth, GLint *iHeight, GLint *iComponents, GLenum *eFormat, GLbyte *pData);
参数1:szFileName 纹理文件的名称
参数2:iWidth 获取纹理文件的宽度
参数3:iHeight获取纹理文件的高度
参数4:iComponents获取纹理文件的组件
参数5:eFormat获取纹理文件的格式
返回值:指向图像数据的指针
*/
pBytes = gltReadTGABits(szTextureFiles[iLoop], &iWidth, &iHeight, &iComponents, &eFormat);
//放大过滤器
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
//缩小过滤器
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
//环绕方式--S
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
//环绕方式--T
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
//载入纹理
/*
glTexImage2D (GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const GLvoid *pixels);
参数1:target,使用的纹理类型GL_TEXTURE_1D\GL_TEXTURE_2D\GL_TEXTURE_3D
参数2:level ,Mip贴图的层次
参数3:internalformat,纹理单元的颜色组成方式(从读取像素图中获得)
参数4:width
参数5:height
参数6:border
参数7:format
参数8:type,像素数据的数据类型-GL_UNSIGNED_BYTE
参数9:pixels,指向纹理图像数据的指针
*/
glTexImage2D(GL_TEXTURE_2D, 0, iComponents, iWidth, iHeight, 0, eFormat, GL_UNSIGNED_BYTE, pBytes);
//生成MIP图层
/*
参数1:GL_TEXTURE_1D\GL_TEXTURE_2D\GL_TEXTURE_3D
*/
glGenerateMipmap(GL_TEXTURE_2D);
free(pBytes);
}
//建立立体图像!!!
GLfloat z;
/*
void Begin(GLenum primitive, GLuint nVerts, GLuint nTextureUnits = 0);
参数1:绘图模式
参数2:顶点个数
参数3:纹理,默认等于0
*/
floorBatch.Begin(GL_TRIANGLE_STRIP, 28,1);//共绘制了7个四边形, 共28个顶点
//参考图 - floor.png
for (z = 60.0f; z >= 0.0f; z -= 10.0f) {
//指定顶点对应纹理的坐标
floorBatch.MultiTexCoord2f(0, 0, 0);
//指定左下角顶点
floorBatch.Vertex3f(-10.0f, -10.0f, z);
//指定右下角顶点以及纹理坐标
floorBatch.MultiTexCoord2f(0, 1, 0);
floorBatch.Vertex3f(10.0f, -10.0f, z);
//指定顶点对应纹理的坐标
floorBatch.MultiTexCoord2f(0, 0, 1.0f);
floorBatch.Vertex3f(-10.0f, -10.0f, z-10.0f);
//指定顶点对应纹理的坐标
floorBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
floorBatch.Vertex3f(10.0f, -10.0f, z-10.0f);
}
floorBatch.End();
//参考图- ceiling.png
ceilingBatch.Begin(GL_TRIANGLE_STRIP, 28, 1);
for(z = 60.0f; z >= 0.0f; z -=10.0f)
{
ceilingBatch.MultiTexCoord2f(0, 0.0f, 1.0f);
ceilingBatch.Vertex3f(-10.0f, 10.0f, z - 10.0f);
ceilingBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
ceilingBatch.Vertex3f(10.0f, 10.0f, z - 10.0f);
ceilingBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
ceilingBatch.Vertex3f(-10.0f, 10.0f, z);
ceilingBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
ceilingBatch.Vertex3f(10.0f, 10.0f, z);
}
ceilingBatch.End();
//参考图 - leftWall.png
leftWallBatch.Begin(GL_TRIANGLE_STRIP, 28, 1);
for(z = 60.0f; z >= 0.0f; z -=10.0f)
{
leftWallBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
leftWallBatch.Vertex3f(-10.0f, -10.0f, z);
leftWallBatch.MultiTexCoord2f(0, 0.0f, 1.0f);
leftWallBatch.Vertex3f(-10.0f, 10.0f, z);
leftWallBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
leftWallBatch.Vertex3f(-10.0f, -10.0f, z - 10.0f);
leftWallBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
leftWallBatch.Vertex3f(-10.0f, 10.0f, z - 10.0f);
}
leftWallBatch.End();
//参考图 - rightWall.png
rightWallBatch.Begin(GL_TRIANGLE_STRIP, 28, 1);
for(z = 60.0f; z >= 0.0f; z -=10.0f)
{
rightWallBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
rightWallBatch.Vertex3f(10.0f, -10.0f, z);
rightWallBatch.MultiTexCoord2f(0, 0.0f, 1.0f);
rightWallBatch.Vertex3f(10.0f, 10.0f, z);
rightWallBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
rightWallBatch.Vertex3f(10.0f, -10.0f, z - 10.0f);
rightWallBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
rightWallBatch.Vertex3f(10.0f, 10.0f, z - 10.0f);
}
rightWallBatch.End();
}
窗口设置
//改变视景体和视口，在改变窗口大小或初始化窗口调用
void ChangeSize(int w, int h)
{
if (h == 0) {
h = 1;
}
glViewport(0, 0, w, h);
//透视投影纵横比
GLfloat fAspect;
fAspect = (GLfloat)w / (GLfloat)h;
//设置透视投影
viewFrustum.SetPerspective(80.0f, fAspect, 1.0, 120.0);
//获取到投影矩阵
projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
//通过变换管线来管理投影矩阵堆栈
transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
}
调用，绘制场景
void RenderScene(void)
{
glClear(GL_COLOR_BUFFER_BIT);
modelViewMatrix.PushMatrix();
modelViewMatrix.Translate(0.0f, 0.0f, viewZ);
//纹理替换矩阵着色器
/*
参数1:GLT_SHADER_TEXTURE_REPLACE
参数2:模型视图矩阵 & 投影矩阵
参数3:纹理层次
*/
shaderManager.UseStockShader(GLT_SHADER_TEXTURE_REPLACE,transformPipeline.GetModelViewProjectionMatrix(),0);
//地板
glBindTexture(GL_TEXTURE_2D, textures[TEXTURE_FLOOR]);
floorBatch.Draw();
//天花板
glBindTexture(GL_TEXTURE_2D, textures[TEXTURE_CEILING]);
ceilingBatch.Draw();
//左右墙壁
glBindTexture(GL_TEXTURE_2D, textures[TEXTURE_BRICK]);
leftWallBatch.Draw();
rightWallBatch.Draw();
modelViewMatrix.PopMatrix();
glutSwapBuffers();
}
效果图
image.png