使用着色器更改纹理颜色

使用着色器更改纹理颜色的解决方法如下所示（使用OpenGL和GLSL作为示例）：

1. 创建并编译着色器程序：

// 顶点着色器
const char* vertexShaderSource = R"(
    #version 330 core
    layout (location = 0) in vec3 aPos;
    layout (location = 1) in vec2 aTexCoord;
    
    out vec2 TexCoord;
    
    void main()
    {
        gl_Position = vec4(aPos, 1.0);
        TexCoord = aTexCoord;
    }
)";
unsigned int vertexShader;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);

// 片段着色器
const char* fragmentShaderSource = R"(
    #version 330 core
    in vec2 TexCoord;
    
    out vec4 FragColor;
    
    uniform sampler2D texture1;
    
    void main()
    {
        FragColor = texture(texture1, TexCoord);
        // 修改纹理颜色
        FragColor.r = 1.0 - FragColor.r; // 将红色通道的值反转
    }
)";
unsigned int fragmentShader;
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);

// 创建着色器程序
unsigned int shaderProgram;
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);

glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);

2. 加载纹理并绑定到着色器程序：

// 加载纹理
unsigned int texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);

// 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);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

// 加载并生成纹理
int width, height, nrChannels;
unsigned char* data = stbi_load("texture.jpg", &width, &height, &nrChannels, 0);
if (data)
{
    GLenum format;
    if (nrChannels == 1)
        format = GL_RED;
    else if (nrChannels == 3)
        format = GL_RGB;
    else if (nrChannels == 4)
        format = GL_RGBA;

    glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);
}
else
{
    std::cout << "Failed to load texture" << std::endl;
}
stbi_image_free(data);

// 绑定纹理到着色器程序
glUseProgram(shaderProgram);
glUniform1i(glGetUniformLocation(shaderProgram, "texture1"), 0);

3. 渲染纹理：

// 渲染循环
while (!glfwWindowShouldClose(window))
{
    // 清空缓冲区
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // 绑定纹理
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture);

    // 绘制矩形
    glUseProgram(shaderProgram);
    glBindVertexArray(VAO);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    // 检查并调用事件，交换缓冲区
    glfwSwapBuffers(window);
    glfwPollEvents();
}

以上代码示例演示了如何使用着色器程序更改纹理颜色。在片段着色器中，我们使用texture()函数获取纹理颜色，并通过修改颜色通道实现了纹理颜色的更改。