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Ich beginne mit OpenGL und folge den Anleitungen und versuche ein strukturiertes Dreieck zu erstellen. Die Shader in diesem Code sind fest codiert, sodass sie zu einer minimalen ausführbaren Datei werden. Es kompiliert reibungslos, aber die Ausgabe ist nur ein farbiges Fenster ohne ein Dreieck. Was mache ich falsch? Hier ist der Code:Textur zum 2D Element hinzufügen
#include <iostream>
// GLEW
#define GLEW_STATIC
#include <GL/glew.h>
// GLFW
#include <GLFW/glfw3.h>
#include <soil.h>
// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
// Window dimensions
const GLuint WIDTH = 800, HEIGHT = 600;
// Texture co-ordinates
GLfloat texCoords[] = {
0.0f, 0.0f, // Lower-left corner
1.0f, 0.0f, // Lower-right corner
0.5f, 1.0f // Top-center corner
};
// Shaders
const GLchar* vertexShaderSource = "#version 330 core\n layout (location = 0) in vec3 position;\r\nlayout (location = 1) in vec3 color;\r\nlayout (location = 2) in vec2 texCoord;\r\n\r\nout vec3 ourColor;\r\nout vec2 TexCoord;\r\n\r\nvoid main()\r\n{\r\n gl_Position = vec4(position, 1.0f);\r\n ourColor = color;\r\n TexCoord = texCoord;\r\n}";
const GLchar* fragmentShaderSource = "#version 330 core\r\nin vec3 ourColor;\r\nin vec2 TexCoord;\r\n\r\nout vec4 color;\r\n\r\nuniform sampler2D ourTexture;\r\n\r\nvoid main()\r\n{\r\n color = texture(ourTexture, TexCoord);\r\n}";
// The MAIN function, from here we start the application and run the game loop
int main()
{
// Init GLFW
glfwInit();
// Set all the required options for GLFW
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
// Create a GLFWwindow object that we can use for GLFW's functions
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
glfwMakeContextCurrent(window);
// Set the required callback functions
glfwSetKeyCallback(window, key_callback);
// Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
glewExperimental = GL_TRUE;
// Initialize GLEW to setup the OpenGL Function pointers
glewInit();
// Define the viewport dimensions
int width, height;
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
// Build and compile our shader program
// Vertex shader
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
// Check for compile time errors
GLint success;
GLchar infoLog[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Fragment shader
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
// Check for compile time errors
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Link shaders
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
// Check for linking errors
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] = {
-0.5f, -0.5f, 0.0f, // Left
0.5f, -0.5f, 0.0f, // Right
0.0f, 0.5f, 0.0f // Top
};
GLuint VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind
glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs)
// Attach image to texture
int t_width, t_height;
unsigned char* image = SOIL_load_image("texm.jpg", &t_width, &t_height, 0, SOIL_LOAD_RGB);
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, t_width, t_height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
SOIL_free_image_data(image);
glBindTexture(GL_TEXTURE_2D, 0);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
// Game loop
while (!glfwWindowShouldClose(window))
{
// Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
glfwPollEvents();
// Render
// Clear the colorbuffer
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Draw our first triangle
glUseProgram(shaderProgram);
glBindTexture(GL_TEXTURE_2D, texture);
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
// Swap the screen buffers
glfwSwapBuffers(window);
}
// Properly de-allocate all resources once they've outlived their purpose
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
// Terminate GLFW, clearing any resources allocated by GLFW.
glfwTerminate();
return 0;
}
// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
Dank und Gruß.