尝试用不同的纹理环绕方式，设定一个从0.0f到2.0f范围内的（而不是原来的0.0f到1.0f）纹理坐标。试试看能不能在箱子的角落放置4个笑脸
1 #include <glad/glad.h>
2 #include <GLFW/glfw3.h>
3 #define STB_IMAGE_IMPLEMENTATION
4 #include <stb/stb_image.h>
5
6 #include <Shader/shader.h>
7
8 #include <iostream>
9
10 void framebuffer_size_callback(GLFWwindow* window, int width, int height);
11 void processInput(GLFWwindow *window);
12
13 // settings
14 const unsigned int SCR_WIDTH = 800;
15 const unsigned int SCR_HEIGHT = 600;
16
17 int main()
18 {
19 // glfw: initialize and configure
20 // ------------------------------
21 glfwInit();
22 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
23 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
24 glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
25
26 #ifdef __APPLE__
27 glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
28 #endif
29
30 // glfw window creation
31 // --------------------
32 GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
33 if (window == NULL)
34 {
35 std::cout << "Failed to create GLFW window" << std::endl;
36 glfwTerminate();
37 return -1;
38 }
39 glfwMakeContextCurrent(window);
40 glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
41
42 // glad: load all OpenGL function pointers
43 // ---------------------------------------
44 if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
45 {
46 std::cout << "Failed to initialize GLAD" << std::endl;
47 return -1;
48 }
49
50 // build and compile our shader zprogram
51 // ------------------------------------
52 Shader ourShader("vs.in", "fs.in");
53
54 // set up vertex data (and buffer(s)) and configure vertex attributes
55 // ------------------------------------------------------------------
56 float vertices[] = {
57 // positions // colors // texture coords
58 0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 2.0f, 2.0f, // top right
59 0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 2.0f, 0.0f, // bottom right
60 -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom left
61 -0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 2.0f // top left
62 };
63 unsigned int indices[] = {
64 0, 1, 3, // first triangle
65 1, 2, 3 // second triangle
66 };
67 unsigned int VBO, VAO, EBO;
68 glGenVertexArrays(1, &VAO);
69 glGenBuffers(1, &VBO);
70 glGenBuffers(1, &EBO);
71
72 glBindVertexArray(VAO);
73
74 glBindBuffer(GL_ARRAY_BUFFER, VBO);
75 glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
76
77 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
78 glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
79
80 // position attribute
81 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
82 glEnableVertexAttribArray(0);
83 // color attribute
84 glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
85 glEnableVertexAttribArray(1);
86 // texture coord attribute
87 glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
88 glEnableVertexAttribArray(2);
89
90
91 // load and create a texture
92 // -------------------------
93 unsigned int texture1, texture2;
94 // texture 1
95 // ---------
96 glGenTextures(1, &texture1);
97 glBindTexture(GL_TEXTURE_2D, texture1);
98 // set the texture wrapping parameters
99 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); // set texture wrapping to GL_REPEAT (default wrapping method)
100 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
101 // set texture filtering parameters
102 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
103 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
104 // load image, create texture and generate mipmaps
105 int width, height, nrChannels;
106 stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
107 // The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.
108 unsigned char *data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
109 if (data)
110 {
111 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
112 glGenerateMipmap(GL_TEXTURE_2D);
113 }
114 else
115 {
116 std::cout << "Failed to load texture" << std::endl;
117 }
118 stbi_image_free(data);
119 // texture 2
120 // ---------
121 glGenTextures(1, &texture2);
122 glBindTexture(GL_TEXTURE_2D, texture2);
123 // set the texture wrapping parameters
124 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)
125 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
126 // set texture filtering parameters
127 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
128 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
129 // load image, create texture and generate mipmaps
130 data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
131 if (data)
132 {
133 // note that the awesomeface.png has transparency and thus an alpha channel, so make sure to tell OpenGL the data type is of GL_RGBA
134 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
135 glGenerateMipmap(GL_TEXTURE_2D);
136 }
137 else
138 {
139 std::cout << "Failed to load texture" << std::endl;
140 }
141 stbi_image_free(data);
142
143 // tell opengl for each sampler to which texture unit it belongs to (only has to be done once)
144 // -------------------------------------------------------------------------------------------
145 ourShader.use(); // don't forget to activate/use the shader before setting uniforms!
146 // either set it manually like so:
147 glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
148 // or set it via the texture class
149 ourShader.setInt("texture2", 1);
150
151
152
153 // render loop
154 // -----------
155 while (!glfwWindowShouldClose(window))
156 {
157 // input
158 // -----
159 processInput(window);
160
161 // render
162 // ------
163 glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
164 glClear(GL_COLOR_BUFFER_BIT);
165
166 // bind textures on corresponding texture units
167 glActiveTexture(GL_TEXTURE0);
168 glBindTexture(GL_TEXTURE_2D, texture1);
169 glActiveTexture(GL_TEXTURE1);
170 glBindTexture(GL_TEXTURE_2D, texture2);
171
172 // render container
173 ourShader.use();
174 glBindVertexArray(VAO);
175 glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
176
177 // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
178 // -------------------------------------------------------------------------------
179 glfwSwapBuffers(window);
180 glfwPollEvents();
181 }
182
183 // optional: de-allocate all resources once they've outlived their purpose:
184 // ------------------------------------------------------------------------
185 glDeleteVertexArrays(1, &VAO);
186 glDeleteBuffers(1, &VBO);
187 glDeleteBuffers(1, &EBO);
188
189 // glfw: terminate, clearing all previously allocated GLFW resources.
190 // ------------------------------------------------------------------
191 glfwTerminate();
192 return 0;
193 }
194
195 // process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
196 // ---------------------------------------------------------------------------------------------------------
197 void processInput(GLFWwindow *window)
198 {
199 if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
200 glfwSetWindowShouldClose(window, true);
201 }
202
203 // glfw: whenever the window size changed (by OS or user resize) this callback function executes
204 // ---------------------------------------------------------------------------------------------
205 void framebuffer_size_callback(GLFWwindow* window, int width, int height)
206 {
207 // make sure the viewport matches the new window dimensions; note that width and
208 // height will be significantly larger than specified on retina displays.
209 glViewport(0, 0, width, height);
210 }
将坐标扩大到0.0f-2.0f，箱子的环绕方式改为GL_CLAMP_TO_EDGE
2019/11/27