1. 概述
QOpenGLTexture
是 Qt5 提供的一个类,用于表示和管理 OpenGL 纹理。它封装了 OpenGL 纹理的创建、分配存储、绑定和设置像素数据等操作,简化了 OpenGL 纹理的使用。
2. 重要函数
-
构造函数:
-
QOpenGLTexture(const QImage &image, QOpenGLTexture::MipMapGeneration genMipMaps = GenerateMipMaps)
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QOpenGLTexture(QOpenGLTexture::Target target)
-
-
纹理配置:
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void allocateStorage()
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void allocateStorage(QOpenGLTexture::PixelFormat pixelFormat, QOpenGLTexture::PixelType pixelType)
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void setFormat(QOpenGLTexture::TextureFormat format)
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void setLayers(int layers)
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void setSize(int width, int height = 1, int depth = 1)
-
-
绑定和解绑:
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void bind()
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void bind(uint unit, QOpenGLTexture::TextureUnitReset reset = DontResetTextureUnit)
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void release()
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void release(uint unit, QOpenGLTexture::TextureUnitReset reset = DontResetTextureUnit)
-
-
设置像素数据:
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void setData(int mipLevel, QOpenGLTexture::PixelFormat sourceFormat, QOpenGLTexture::PixelType sourceType, const void *data, const QOpenGLPixelTransferOptions *const options = nullptr)
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void setData(const QImage &image, QOpenGLTexture::MipMapGeneration genMipMaps = GenerateMipMaps)
-
-
生成 Mipmaps:
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void generateMipMaps()
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void generateMipMaps(int baseLevel, bool resetBaseLevel = true)
-
-
获取纹理属性:
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int width() const
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int height() const
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int depth() const
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GLuint textureId() const
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3. 常用枚举类型
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BindingTarget:纹理绑定目标,如
BindingTarget2D
、BindingTargetCubeMap
等。 -
ComparisonFunction:深度和模板比较函数。
-
ComparisonMode:比较模式,如
CompareRefToTexture
。 -
CubeMapFace:立方体贴图的各个面,如
CubeMapPositiveX
。 -
DepthStencilMode:深度和模板模式。
-
Feature:纹理特性,如
TextureRectangle
、TextureArrays
。 -
Filter:纹理过滤方式,如
Nearest
、Linear
。 -
MipMapGeneration:是否生成 Mipmaps,
GenerateMipMaps
或DontGenerateMipMaps
。 -
PixelFormat:像素格式,如
RGBA8888
。 -
PixelType:像素类型,如
UnsignedByte
。 -
SwizzleComponent:颜色通道,如
SwizzleRed
。 -
SwizzleValue:颜色值,如
RedValue
。 -
Target:纹理目标,如
Target2D
。 -
TextureFormat:纹理格式,如
RGB8_UNorm
。 -
WrapMode:纹理环绕模式,如
Repeat
、ClampToEdge
。
#include "widget.h"float vertices[] = {// positions // colors // texture coords0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom left-0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices[] = {0, 1, 3, // first triangle1, 2, 3 // second triangle
};MyGLWidget::MyGLWidget(QWidget *parent) : QOpenGLWidget(parent)
{}MyGLWidget::~MyGLWidget()
{glDeleteVertexArrays(1, &VAO);glDeleteBuffers(1, &VBO);glDeleteBuffers(1, &EBO);
}void MyGLWidget::initializeGL()
{initializeOpenGLFunctions(); // 初始化 OpenGL 函数bool success;m_shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex,":/shader/shader.vert");m_shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment,":/shader/shader.frag");success=m_shaderProgram.link();if(!success) qDebug()<<"ERR:"<<m_shaderProgram.log();//创建、绑定VAOglGenVertexArrays(1, &VAO);glBindVertexArray(VAO);//创建、绑定VBO + 填充数据glGenBuffers(1, &VBO);glBindBuffer(GL_ARRAY_BUFFER, VBO);glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);//设置顶点属性指针glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);glEnableVertexAttribArray(0);// 颜色属性glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3* sizeof(float)));glEnableVertexAttribArray(1);//纹理坐标glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));glEnableVertexAttribArray(2);//解绑缓冲区和 VAOglBindBuffer(GL_ARRAY_BUFFER, 0);glBindVertexArray(0);//创建、绑定纹理m_diffuseTex = new QOpenGLTexture(QImage(":/img/container.png").mirrored());m_specularTex = new QOpenGLTexture(QImage(":/img/awesomeface.png").mirrored());m_shaderProgram.bind();m_shaderProgram.setUniformValue("texture1", 0);m_shaderProgram.setUniformValue("texture2", 1);;
}void MyGLWidget::paintGL()
{glClearColor(0.2f, 0.3f, 0.3f, 1.0f);glClear(GL_COLOR_BUFFER_BIT); // 清除颜色缓冲区m_shaderProgram.bind();m_diffuseTex->bind(0);m_specularTex->bind(1);glBindVertexArray(VAO);//glDrawArrays(GL_TRIANGLES, 0, 3);glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);glBindVertexArray(0);
}void MyGLWidget::resizeGL(int w, int h)
{glViewport(0, 0, w, h); // 设置视口大小
}unsigned int MyGLWidget::loadTexture(const char *fileName, bool alpha)
{unsigned int texture;glGenTextures(1, &texture); // 生成纹理 IDglBindTexture(GL_TEXTURE_2D, texture); // 绑定纹理// 设置纹理参数glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
#if 0// 加载图片并转换为 OpenGL 格式QImage image;if (!image.load(fileName)){qWarning() << "Failed to load texture image";return 0;}image = QGLWidget::convertToGLFormat(image); // 转换为 OpenGL 格式unsigned char *data = image.bits();// 生成纹理glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width(), image.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, data);glGenerateMipmap(GL_TEXTURE_2D); // 生成多级渐远纹理
#elseQFile file(fileName);file.copy(file.fileName(), QFileInfo(file).fileName());int width, height, nrChannels;stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.unsigned char *data = stbi_load(QFileInfo(file).fileName().toStdString().c_str(), &width, &height, &nrChannels, 0);if (data)//awesomeface container{if(alpha)glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);elseglTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);glGenerateMipmap(GL_TEXTURE_2D);}else{std::cout << "Failed to load texture1" << std::endl;}stbi_image_free(data);
#endifreturn texture;
}
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