设定金字塔坐标
金字塔.png
注意纹理坐标的设置方式:
//设置顶点对应的纹理坐标
// s , t 相当于 x , y
// MultiTexCoord2f(GLuint texture, GLclampf s, GLclampf t);
//参数1:纹理的层次
//参数2:s坐标
//参数3:t坐标
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
绘制金字塔纹理
1. 顶点/纹理坐标数据设置及图形绘制
GLBatch pyramidBatch;//绘制批次类
//1.pyramidBatch
//通过三角形批次类pyramidBatch 来组件图形
//参数1:类型
//参数2:顶点数 6 * 3 = 18
//参数3:需要使用到纹理,默认为0,可以不写这个参数
pyramidBatch.Begin(GL_TRIANGLES, 18,1);
//2.金字塔各个面的点坐标设置
//金字塔底部
//底部四边形 = 三角形X + 三角形Y
//三角形X
//----------vBlackLeft------------
//设置法线坐标-光照
pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
//设置顶点对应的纹理坐标
// MultiTexCoord2f(GLuint texture, GLclampf s, GLclampf t);
//参数1:纹理的层次
//参数2:s坐标
//参数3:t坐标
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
//设置顶点坐标
pyramidBatch.Vertex3f(-1.0f, -1.0f, -1.0f);
//------vBackRight------------
pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
pyramidBatch.Vertex3f(1.0f, -1.0f, -1.0f);
//------vFrontRight点------------
pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
pyramidBatch.Vertex3f(1.0f, -1.0f, 1.0f);
//三角形Y
pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
pyramidBatch.MultiTexCoord2f(0, 0.0f, 1.0f);
pyramidBatch.Vertex3f(-1.0f, -1.0f, 1.0f);
pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
pyramidBatch.Vertex3f(-1.0f, -1.0f, -1.0f);
pyramidBatch.Normal3f(0.0f, -1.0f, 0.0f);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 1.0f);
pyramidBatch.Vertex3f(1.0f, -1.0f, 1.0f);
//塔顶
M3DVector3f vApex = {0.0f,1.0f,0.0f};
M3DVector3f vFrontLeft = {-1.0f,-1.0f,1.0f};
M3DVector3f vFrontRight = {1.0f,-1.0f,1.0f};
M3DVector3f vBackLeft = {-1.0f,-1.0f,-1.0f};
M3DVector3f vBackRight = {1.0f,-1.0f,-1.0f};
//目的:为了临时存储法线向量
M3DVector3f n;
//金字塔的前面
//三角形:(Apex,vFrontLeft,vFrontRight)
//找法线
//m3dFindNormal(M3DVector3f result, const M3DVector3f point1, const M3DVector3f point2,const M3DVector3f point3);
//参数1:结果
//参数2-4:3个顶点
m3dFindNormal(n, vApex, vFrontLeft, vFrontRight);
//vApex
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.5, 1.0f);
pyramidBatch.Vertex3fv(vApex);
//vFrontLeft
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
pyramidBatch.Vertex3fv(vFrontLeft);
//vFrongRight
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
pyramidBatch.Vertex3fv(vFrontRight);
//金字塔的左边
//三角形:(Apex,vBackLeft,vFrontLeft)
m3dFindNormal(n, vApex, vBackLeft, vFrontLeft);
//vApex
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
pyramidBatch.Vertex3fv(vApex);
//vBackLeft
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
pyramidBatch.Vertex3fv(vBackLeft);
//vFrontLeft
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
pyramidBatch.Vertex3fv(vFrontLeft);
//金字塔右边
//三角形：（vApex, vFrontRight, vBackRight）
m3dFindNormal(n, vApex, vFrontRight, vBackRight);
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
pyramidBatch.Vertex3fv(vApex);
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
pyramidBatch.Vertex3fv(vFrontRight);
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
pyramidBatch.Vertex3fv(vBackRight);
//金字塔后边
//三角形：（vApex, vBackRight, vBackLeft）
m3dFindNormal(n, vApex, vBackRight, vBackLeft);
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.5f, 1.0f);
pyramidBatch.Vertex3fv(vApex);
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
pyramidBatch.Vertex3fv(vBackRight);
pyramidBatch.Normal3fv(n);
pyramidBatch.MultiTexCoord2f(0, 1.0f, 0.0f);
pyramidBatch.Vertex3fv(vBackLeft);
//结束批次设置
pyramidBatch.End();
2.加载2D纹理
// 将TGA文件加载为2D纹理。
//参数1:纹理文件名称
//参数2:缩小时过滤器使用的哪一种
//参数3:放大小时过滤器使用的哪一种
//参数4:纹理坐标环绕方式
bool LoadTGATexture(const char *szFileName, GLenum minFilter, GLenum magFilter, GLenum wrapMode)
{
GLbyte *pBits;
int nWidth,nHeight,nComponents;
GLenum eFormat;
//1.读取纹理的像素
//参数1:纹理文件的名称
//参数2:文件的宽度地址
//参数3:文件的高度地址
//参数4:文件的组件地址
//参数5:文件格式地址
//返回值:pBits ,指向图像数据的指针
pBits = gltReadTGABits(szFileName, &nWidth, &nHeight, &nComponents, &eFormat);
if (pBits == NULL) {
printf("读取纹理像素失败\n");
return false;
}
//2.设置纹理参数
//设置s,t的环绕方式
//glTexParameteri (GLenum target, GLenum pname, GLint param);
//参数1:纹理维度
//参数2:为S/T坐标设置环绕模式
//参数3:wrapMode,环绕模式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrapMode);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrapMode);
//设置放大\缩小的过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, minFilter);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, magFilter);
//3.精密包装像素数据
//glPixelStorei (GLenum pname, GLint param);
//参数1:GL_UNPACK_ALIGNMENT ,OpenGL 如何从数据缓存区中解包图像数据
//参数2:设置GL_UNPACK_ALIGNMENT的值
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
//4.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:纹理的维度
//参数2:mip贴图层次
//参数3:加载纹理颜色成分(从读取像素图获取的)
//参数4:加载纹理的宽
//参数5:加载纹理的高
//参数6:纹理的边框
//参数7:像素数据的类型
//参数8:指向纹理数据的指针
//详细可参考PPT
glTexImage2D(GL_TEXTURE_2D, 0, nComponents, nWidth, nHeight, 0, eFormat, GL_UNSIGNED_BYTE, pBits);
//使用完释放
free(pBits);
//只有minFilter 等于以下四种模式，才可以生成Mip贴图
//GL_NEAREST_MIPMAP_NEAREST具有非常好的性能，并且闪烁现象非常弱
//GL_LINEAR_MIPMAP_NEAREST常常用于对游戏进行加速，它使用了高质量的线性过滤器
//GL_LINEAR_MIPMAP_LINEAR 和GL_NEAREST_MIPMAP_LINEAR 过滤器在Mip层之间执行了一些额外的插值，以消除他们之间的过滤痕迹。
//GL_LINEAR_MIPMAP_LINEAR 三线性Mip贴图。纹理过滤的黄金准则，具有最高的精度。
if(minFilter == GL_LINEAR_MIPMAP_LINEAR ||
minFilter == GL_LINEAR_MIPMAP_NEAREST ||
minFilter == GL_NEAREST_MIPMAP_LINEAR ||
minFilter == GL_NEAREST_MIPMAP_NEAREST)
//加载Mip,纹理生成所有的Mip层
//参数：GL_TEXTURE_1D、GL_TEXTURE_2D、GL_TEXTURE_3D
glGenerateMipmap(GL_TEXTURE_2D);
return true;
}
3.SetUp
void SetupRC()
{
glClearColor(0.7f, 0.7f,0.7f, 1.0f);
shaderManager.InitializeStockShaders();
//开启深度测试
glEnable(GL_DEPTH_TEST);
//纹理对象的处理
//1.分配纹理对象
// glGenTextures (GLsizei n, GLuint *textures);
//参数1:纹理对象的个数
//参数2:纹理对象的指针
glGenTextures(1, &textureID);
//2.绑定纹理状态
//glBindTexture (GLenum target, GLuint texture);
//参数1:纹理的状态,GL_TEXTURE_1D\GL_TEXTURE_2D\GL_TEXTURE_3D
glBindTexture(GL_TEXTURE_2D, textureID);
//3.将TGA文件加载成2D纹理
//函数是开发者自己设计的
//参数1:纹理文件名称
//参数2:缩小时过滤器使用的哪一种
//参数3:放大小时过滤器使用的哪一种
//参数4:纹理坐标环绕方式
LoadTGATexture("brick.tga", GL_LINEAR, GL_LINEAR, GL_CLAMP_TO_EDGE);
//4.设置渲染图像的顶点--金字塔
MakePyramid(pyramidBatch);
cameraFrame.MoveForward(-10.0);
}
4.渲染
void RenderScene(void)
{
//光照位置
static GLfloat vLightPos[] = {1.0f,1.0f,0.0f};
//关照颜色
static GLfloat vWhite[] = {1.0f,0.0f,0.0f,1.0f};
//glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER|GL_STENCIL_BUFFER_BIT);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
modelViewMatrix.PushMatrix();
//观察者
M3DMatrix44f mCamera;
cameraFrame.GetCameraMatrix(mCamera);
modelViewMatrix.MultMatrix(mCamera);
//
M3DMatrix44f mObjectFrame;
objectFrame.GetMatrix(mObjectFrame);
modelViewMatrix.MultMatrix(mObjectFrame);
//错误地方!!!
//glBindTexture(GL_TEXTURE_2D, 0);
glBindTexture(GL_TEXTURE_2D, textureID);
//点光源着色器
//参数1:GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF
//参数2:模型视图矩阵
//参数3:投影矩阵
//参数4:光源的位置
//参数5:光的颜色
//参数6:图形颜色(如使用了纹理,则设置为0)
shaderManager.UseStockShader(GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF,transformPipeline.GetModelViewMatrix(),transformPipeline.GetProjectionMatrix(),vLightPos,vWhite,0);
pyramidBatch.Draw();
modelViewMatrix.PopMatrix();
glutSwapBuffers();
}
效果图
image.png
image.png
