建设网站有什么作用,网站建设与维护是什么意思,外包服务平台,网站欣赏网站欣赏深度测试#xff1a;OpenGL将一个片段的深度值与深度缓冲的内容进行对比。执行一个深度测试#xff0c;测试通过则深度缓冲将会更新为新的深度值。测试失败则片段被丢弃。 深度测试片段着色器及模版测试之后执行。 片段着色器中内置变量gl_FragCoord的z值即为深度值。
提前深…深度测试OpenGL将一个片段的深度值与深度缓冲的内容进行对比。执行一个深度测试测试通过则深度缓冲将会更新为新的深度值。测试失败则片段被丢弃。 深度测试片段着色器及模版测试之后执行。 片段着色器中内置变量gl_FragCoord的z值即为深度值。
提前深度测试允许深度测试在片段着色器之前运行。片段着色器通常开销很大。使用提前深度测试时片段着色器不可写入深度值因为OpenGl不能提前知道深度值。
默认禁用glEnable(GL_DEPTH_TEST);启用
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);清楚上一帧深度缓冲
实际运用的深度缓冲是非线性的
深度冲突两个平面或三角形z值一样两个形状会不断切换前后顺序
防止深度冲突 1.不要把多个物体放的太近导致它们的一些三角形重叠 2.将进平面设置远一些因为精度在靠近进平面时较高。注意进平面太远会导致近处的一些物体被裁减掉 3.牺牲一些性能使用更高精度的深度缓冲。大部分深度缓冲的精度都是24位但现在大部分显卡支持32位
main.cpp
#define GLEW_STATIC
#include GL/glew.h
#include GLFW/glfw3.h
#include iostream
#include shader.h
#include stb_image.h
#include glm.hpp
#include gtc/matrix_transform.hpp
#include gtc/type_ptr.hpp
#include Camera.h
#include Model.hCamera* myCamera new Camera(glm::vec3(0.0f, 0.0f, 3.0f), glm::vec3(0.0f, 0.0f, -1.0f), glm::vec3(0.0f, 1.0f, 0.0f));void mouse_callback(GLFWwindow* window, double xpos, double ypos) {myCamera-mouseCb(xpos, ypos);
};void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{myCamera-scrollCb(xoffset, yoffset);
}GLfloat deltaTime 0.0f;
GLfloat lastFrame 0.0f;void processInput(GLFWwindow* window) {GLfloat currentFrame glfwGetTime();deltaTime currentFrame - lastFrame;lastFrame currentFrame;if (glfwGetKey(window, GLFW_KEY_ESCAPE) GLFW_PRESS)glfwSetWindowShouldClose(window, true);if (glfwGetKey(window, GLFW_KEY_W) GLFW_PRESS) {myCamera-pressKeyW(deltaTime);}if (glfwGetKey(window, GLFW_KEY_S) GLFW_PRESS) {myCamera-pressKeyS(deltaTime);}if (glfwGetKey(window, GLFW_KEY_A) GLFW_PRESS) {myCamera-pressKeyA(deltaTime);}if (glfwGetKey(window, GLFW_KEY_D) GLFW_PRESS) {myCamera-pressKeyD(deltaTime);}
}glm::vec3 pointLightPositions[] {glm::vec3(2.0f, 10.2f, 2.0f),glm::vec3(-2.3f, 7.3f, -4.0f)
};float cubeVertices[] {// positions // texture Coords-0.5f, -0.5f, -0.5f, 0.0f, 0.0f,0.5f, -0.5f, -0.5f, 1.0f, 0.0f,0.5f, 0.5f, -0.5f, 1.0f, 1.0f,0.5f, 0.5f, -0.5f, 1.0f, 1.0f,-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,-0.5f, -0.5f, -0.5f, 0.0f, 0.0f,-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,0.5f, -0.5f, 0.5f, 1.0f, 0.0f,0.5f, 0.5f, 0.5f, 1.0f, 1.0f,0.5f, 0.5f, 0.5f, 1.0f, 1.0f,-0.5f, 0.5f, 0.5f, 0.0f, 1.0f,-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,-0.5f, 0.5f, 0.5f, 1.0f, 0.0f,-0.5f, 0.5f, -0.5f, 1.0f, 1.0f,-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,-0.5f, 0.5f, 0.5f, 1.0f, 0.0f,0.5f, 0.5f, 0.5f, 1.0f, 0.0f,0.5f, 0.5f, -0.5f, 1.0f, 1.0f,0.5f, -0.5f, -0.5f, 0.0f, 1.0f,0.5f, -0.5f, -0.5f, 0.0f, 1.0f,0.5f, -0.5f, 0.5f, 0.0f, 0.0f,0.5f, 0.5f, 0.5f, 1.0f, 0.0f,-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,0.5f, -0.5f, -0.5f, 1.0f, 1.0f,0.5f, -0.5f, 0.5f, 1.0f, 0.0f,0.5f, -0.5f, 0.5f, 1.0f, 0.0f,-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,0.5f, 0.5f, -0.5f, 1.0f, 1.0f,0.5f, 0.5f, 0.5f, 1.0f, 0.0f,0.5f, 0.5f, 0.5f, 1.0f, 0.0f,-0.5f, 0.5f, 0.5f, 0.0f, 0.0f,-0.5f, 0.5f, -0.5f, 0.0f, 1.0f
};
float planeVertices[] {// positions // texture Coords (note we set these higher than 1 (together with GL_REPEAT as texture wrapping mode). this will cause the floor texture to repeat)5.0f, -0.5f, 5.0f, 2.0f, 0.0f,-5.0f, -0.5f, 5.0f, 0.0f, 0.0f,-5.0f, -0.5f, -5.0f, 0.0f, 2.0f,5.0f, -0.5f, 5.0f, 2.0f, 0.0f,-5.0f, -0.5f, -5.0f, 0.0f, 2.0f,5.0f, -0.5f, -5.0f, 2.0f, 2.0f
};int main()
{glfwInit();glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);GLFWwindow* window glfwCreateWindow(800, 600, test, nullptr, nullptr);if (window nullptr){std::cout Failed to create GLFW window std::endl;glfwTerminate();return -1;}glfwMakeContextCurrent(window);//glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);glfwSetCursorPosCallback(window, mouse_callback);glfwSetScrollCallback(window, scroll_callback);glewExperimental GL_TRUE;if (glewInit() ! GLEW_OK){std::cout Failed to initialize GLEW std::endl;glfwTerminate();return -1;}glViewport(0, 0, 800, 600);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);glEnableVertexAttribArray(0);glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));glEnableVertexAttribArray(1);glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));glEnableVertexAttribArray(2);glEnableVertexAttribArray(0);glBindVertexArray(0);GLuint cubeVAO, cubeVBO;glGenVertexArrays(1, cubeVAO);glBindVertexArray(cubeVAO);glGenBuffers(1, cubeVBO);glBindBuffer(GL_ARRAY_BUFFER, cubeVBO);glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertices), cubeVertices, GL_STATIC_DRAW);glEnableVertexAttribArray(0);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);glEnableVertexAttribArray(1);glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));glBindVertexArray(0);unsigned int planeVAO, planeVBO;glGenVertexArrays(1, planeVAO);glGenBuffers(1, planeVBO);glBindVertexArray(planeVAO);glBindBuffer(GL_ARRAY_BUFFER, planeVBO);glBufferData(GL_ARRAY_BUFFER, sizeof(planeVertices), planeVertices, GL_STATIC_DRAW);glEnableVertexAttribArray(0);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);glEnableVertexAttribArray(1);glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));glBindVertexArray(0);GLuint tex;glGenTextures(1, tex);int width, height, nrComponents;unsigned char* image stbi_load(container.jpg, width, height, nrComponents, 0);if (image) {GLenum format;if (nrComponents 1)format GL_RED;else if (nrComponents 3)format GL_RGB;else if (nrComponents 4)format GL_RGBA;glBindTexture(GL_TEXTURE_2D, tex);glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, format, GL_UNSIGNED_BYTE, image);glGenerateMipmap(GL_TEXTURE_2D);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);stbi_image_free(image);}glm::mat4 model;glm::mat4 view;glm::mat4 projection;glEnable(GL_DEPTH_TEST);//深度测试函数glDepthFunc(GL_LESS);/** GL_ALWAYS 永远通过深度测试* GL_NEVER 永远不通过深度测试* GL_LESS 在片段深度值小于缓冲的深度值时通过测试* GL_EQUAL 在片段深度值等于缓冲区的深度值时通过测试* GL_LEQUAL 在片段深度值小于等于缓冲区的深度值时通过测试* GL_GREATER 在片段深度值大于缓冲区的深度值时通过测试* GL_NOTEQUAL 在片段深度值不等于缓冲区的深度值时通过测试* GL_GEQUAL 在片段深度值大于等于缓冲区的深度值时通过测试*/Shader* testShader new Shader(test.vert, test.frag);Shader* lightShader new Shader(test.vert, light.frag);while (!glfwWindowShouldClose(window)){processInput(window);glfwPollEvents();glClearColor(0.1f, 0.1f, 0.1f, 1.0f);glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);testShader-Use();glUniform1i(glGetUniformLocation(testShader-getProgram(), texture1), 0);glBindVertexArray(cubeVAO);glActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, tex);view myCamera-getViewMat4();glUniformMatrix4fv(glGetUniformLocation(testShader-getProgram(), view), 1, GL_FALSE, glm::value_ptr(view));projection glm::perspective(glm::radians(myCamera-getFov()), 800.0f / 600.0f, 0.1f, 100.0f);glUniformMatrix4fv(glGetUniformLocation(testShader-getProgram(), projection), 1, GL_FALSE, glm::value_ptr(projection));model glm::translate(model, glm::vec3(-1.0f, 0.0f, -1.0f));glUniformMatrix4fv(glGetUniformLocation(testShader-getProgram(), model), 1, GL_FALSE, glm::value_ptr(model));glDrawArrays(GL_TRIANGLES, 0, 36);model glm::mat4(1.0f);model glm::translate(model, glm::vec3(2.0f, 0.0f, 0.0f));glUniformMatrix4fv(glGetUniformLocation(testShader-getProgram(), model), 1, GL_FALSE, glm::value_ptr(model));glDrawArrays(GL_TRIANGLES, 0, 36);glBindVertexArray(planeVAO);glUniformMatrix4fv(glGetUniformLocation(testShader-getProgram(), model), 1, GL_FALSE, glm::value_ptr(glm::mat4(1.0f)));glDrawArrays(GL_TRIANGLES, 0, 6);glBindVertexArray(0);glfwSwapBuffers(window);}glfwTerminate();return 0;
}顶点着色器
#version 330 core
layout (location 0) in vec3 aPos;
layout (location 1) in vec2 aTexCoords;out vec2 TexCoords;uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;void main()
{TexCoords aTexCoords; gl_Position projection * view * model * vec4(aPos, 1.0);
}片段着色器
#version 330 core
out vec4 FragColor;in vec2 TexCoords;uniform sampler2D texture1;float near 0.1;
float far 100.0; float LinearizeDepth(float depth)
{float z depth * 2.0 - 1.0; // back to NDC [0,1]变换到[-1,1]标准化设备坐标/裁剪空间return (2.0 * near * far) / (far near - z * (far - near));
}void main()
{ FragColor texture(texture1, TexCoords);//FragColor vec4(vec3(gl_FragCoord.z), 1.0);//float depth LinearizeDepth(gl_FragCoord.z) / far; // 为了演示除以 far//FragColor vec4(vec3(depth), 1.0);
}
