LearnOpenGL - 纹理贴图 源代码

      为了方便使用与代码观看,将Shader抽出来作为一个单独的Shader类,叫ShaderTex。其次,将vs与fs的代码写成单独的shader文件。

Shader类:将Shader构建代码抽出,文件名 shader_textures.h

#ifndef _SHADER_TEXTURES_H_
#define _SHADER_TEXTURES_H_
//纹理器

#include <glad/glad.h>
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>

class ShaderTex
{
public:
	unsigned int ID;  //程序id  即前文代码中的shaderProgram

	ShaderTex(const GLchar* vertexPath, const GLchar* fragmentPath)
	{
		std::string vertexCode;
		std::string fragmentCode;
		std::ifstream vShaderFile;
		std::ifstream fShaderFile;
		//保证可以抛出异常
		vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
		fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
		try
		{
			vShaderFile.open(vertexPath);
			fShaderFile.open(fragmentPath);
			std::stringstream vShaderStream, fShaderStream;
			//读取文件
			vShaderStream << vShaderFile.rdbuf();
			fShaderStream << fShaderFile.rdbuf();
			//关闭文件处理器
			vShaderFile.close();
			fShaderFile.close();
			//转换数据到string
			vertexCode = vShaderStream.str();
			fragmentCode = fShaderStream.str();
		}
		catch (std::ifstream::failure e)
		{
			std::cout << "error: shader file read failed   " << std::endl;
			return;
		}
		const char* vShaderCode = vertexCode.c_str();
		const char* fShaderCode = fragmentCode.c_str();

		int vertexShader = glCreateShader(GL_VERTEX_SHADER); //创建vs
		glShaderSource(vertexShader, 1, &vShaderCode, NULL); //shader源码附加到shader身上
		glCompileShader(vertexShader); //编译
		int success;
		glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success); //获得编译结果
		if (!success)
		{
			char infoLog[512];
			glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
			std::cout << "error: vertexshader compilation failed  " << infoLog << std::endl;
			return;
		}
		int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER); //创建fs
		glShaderSource(fragmentShader, 1, &fShaderCode, NULL);
		glCompileShader(fragmentShader);
		glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
		if (!success)
		{
			char infoLog[512];
			glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
			std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
			return;
		}

		ID = glCreateProgram(); //创建程序对象
		glAttachShader(ID, vertexShader);   //shader附加到程序对象
		glAttachShader(ID, fragmentShader); //shader附加到程序对象
		glLinkProgram(ID); //链接他们
		glGetProgramiv(ID, GL_LINK_STATUS, &success); //获得链接结果
		if (!success)
		{
			char infoLog[512];
			glGetProgramInfoLog(ID, 512, NULL, infoLog);
			std::cout << "error: programshader link failed   " << infoLog << std::endl;
			return;
		}
		glDeleteShader(vertexShader);   //附加完毕,已经没用了
		glDeleteShader(fragmentShader);
	}
	void use()
	{
		glUseProgram(ID);
	}
	void setBool(const std::string& name, bool value) const
	{
		glUniform1i(glGetUniformLocation(ID, name.c_str()), int(value));
	}
	void setInt(const std::string& name, int value) const
	{
		glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
	}
	void setFloat(const std::string& name, float value) const
	{
		glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
	}
};

#endif

shader代码:文件名,shader_textures.fs 、shader_textures.vs

#version 330 core

out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

uniform sampler2D ourTexture;

void main()
{
	FragColor = texture(ourTexture, TexCoord);
}
#version 330 core

layout(location = 0) in vec3 pos;
layout(location = 1) in vec3 color;
layout(location = 2) in vec2 texcoord;

out vec3 ourColor;
out vec2 TexCoord;

void main()
{
	gl_Position = vec4(pos, 1.0);
	ourColor = color;
	TexCoord = texcoord;
}

使用文件:

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "shader.h"
#include "shader_textures.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"


void processInput(GLFWwindow* window);
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
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, "LearnOpenGL", NULL, NULL);
	if (!window)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return 0;
	}
	glfwMakeContextCurrent(window);
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to init GLAD" << std::endl;
		return 0;
	}
	ShaderTex ourShader("shader_textures.vs", "shader_textures.fs");

	//前三个数表示坐标,后三个数表示颜色,最后是纹理坐标
	float vertices[] = {
		-0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
		-0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
		0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f,
		0.5f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f
	};
	int indices[] = {
		0,1,2,
		0,3,2
	};

	unsigned int VBO, VAO, EBO;
	glGenBuffers(1, &VBO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);
	glGenBuffers(1, &EBO);

	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);
	//位置属性0的继续配置  读取三个,步长6*float,偏移0
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	//位置属性1的  读取三个,步长6*float,偏移3*float      位置属性的含义对应 vShader中的location
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);
	//位置属性2的  读取两个
	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(6*sizeof(float)));
	glEnableVertexAttribArray(2);

    stbi_set_flip_vertically_on_load(true); //翻转y轴

	//texture 1
	unsigned int texture;
	glGenTextures(1, &texture);
	glBindTexture(GL_TEXTURE_2D, texture);
	//为绑定的纹理对象设置环绕、过滤方式
	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_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

	int width, height, nrChannels;
	unsigned char* data = stbi_load("aaa.jpg", &width, &height, &nrChannels, 0);
	if (!data) 
	{
		std::cout << "error: stbi_load failed" << std::endl;
		return 0;
	}
    //教程里这里都用的GL_RGB  我用的图片需要使用GL_RGBA,否则最后渲染很奇怪
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
	glGenerateMipmap(GL_TEXTURE_2D);
	//释放内存
	stbi_image_free(data);

	while (!glfwWindowShouldClose(window))
	{
		processInput(window); //输入
		glClearColor(0.2f, 0.3f, 0.4f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);
		
		glActiveTexture(GL_TEXTURE0);          //**纹理单元
		glBindTexture(GL_TEXTURE_2D, texture); //绑定
		ourShader.use();
		glBindVertexArray(VAO);
		glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

		glfwSwapBuffers(window); //双缓冲Buffer
		glfwPollEvents(); //检查事件触发 是否结束渲染
	}

	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	glfwTerminate();
	return 0;
}
void processInput(GLFWwindow* window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
	glViewport(0, 0, width, height);
}

结果图:

LearnOpenGL - 纹理贴图 源代码

 

将颜色与最终背景图融合,只需要改动shader_textures.fs文件,增加vec4的颜色输出,如下:

#version 330 core

out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

uniform sampler2D ourTexture;

void main()
{
	FragColor = texture(ourTexture, TexCoord) * vec4(ourColor, 1.0f);
}

最终效果图:

LearnOpenGL - 纹理贴图 源代码

 

组合两张贴图,修改shader_textures.fs代码如下:

#version 330 core

out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

uniform sampler2D texture1;
uniform sampler2D texture2;

void main()
{
	FragColor = mix(texture(texture1, TexCoord), texture(texture2, TexCoord), 0.2) *vec4(ourColor, 1.0f);
}

修改主程序:

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "shader.h"
#include "shader_textures.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"


void processInput(GLFWwindow* window);
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
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, "LearnOpenGL", NULL, NULL);
	if (!window)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return 0;
	}
	glfwMakeContextCurrent(window);
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to init GLAD" << std::endl;
		return 0;
	}
	ShaderTex ourShader("shader_textures.vs", "shader_textures.fs");

	//前三个数表示坐标,后三个数表示颜色,最后是纹理坐标
	float vertices[] = {
		0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f,
		0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,
		-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
		-0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f
	};
	int indices[] = {
		0,1,3,
		1,2,3
	};

	unsigned int VBO, VAO, EBO;
	glGenBuffers(1, &VBO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);
	glGenBuffers(1, &EBO);

	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);
	//位置属性0的继续配置  读取三个,步长6*float,偏移0
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	//位置属性1的  读取三个,步长6*float,偏移3*float      位置属性的含义对应 vShader中的location
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);
	//位置属性2的  读取两个
	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(6*sizeof(float)));
	glEnableVertexAttribArray(2);

	stbi_set_flip_vertically_on_load(true); //翻转y轴

	//texture 1
	unsigned int texture1;
	glGenTextures(1, &texture1);
	glBindTexture(GL_TEXTURE_2D, texture1);
	//为绑定的纹理对象设置环绕、过滤方式
	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);
	int width, height, nrChannels;
	unsigned char* data = stbi_load("aaa.jpg", &width, &height, &nrChannels, 0);
	if (!data) 
	{
		std::cout << "error: stbi_load failed" << std::endl;
		return 0;
	}
	else
	{
		//教程里这里都用的GL_RGB  我用的图片需要使用GL_RGBA,否则最后渲染很奇怪
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);
	}
	//释放内存
	stbi_image_free(data);

	//texture  2
	unsigned int texture2;
	glGenTextures(1, &texture2);
	glBindTexture(GL_TEXTURE_2D, texture2);
	//为绑定的纹理对象设置环绕、过滤方式
	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);
	data = stbi_load("bbb.png", &width, &height, &nrChannels, 0);
	if (!data)
	{
		std::cout << "error: stbi_load failed111" << std::endl;
		return 0;
	}
	else
	{
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);
	}
	//释放内存
	stbi_image_free(data);

	ourShader.use();
	glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
	ourShader.setInt("texture2", 1);

	while (!glfwWindowShouldClose(window))
	{
		processInput(window); //输入
		glClearColor(0.2f, 0.3f, 0.4f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);
		
		glActiveTexture(GL_TEXTURE0);          //**纹理单元
		glBindTexture(GL_TEXTURE_2D, texture1); //绑定
		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, texture2);
		ourShader.use();
		glBindVertexArray(VAO);
		glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

		glfwSwapBuffers(window); //双缓冲Buffer
		glfwPollEvents(); //检查事件触发 是否结束渲染
	}

	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	glfwTerminate();
	return 0;
}
void processInput(GLFWwindow* window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
	glViewport(0, 0, width, height);
}

最终效果如下:

LearnOpenGL - 纹理贴图 源代码

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