18a3472df7
* Added hello world example to OpenGL guide * Fixed command * Fixed command * Added command for building * Update index.md
70 lines
1.5 KiB
Markdown
70 lines
1.5 KiB
Markdown
---
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title: Hello World
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---
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# Hello World
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This is a Hello World application of OpenGL
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```C
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#include <GLFW/glfw3.h>
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GLFWwindow* window = NULL;
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int main(void)
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{
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// Initialize GLFW
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if (!glfwInit())
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return -1;
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// Create window with dimensions 640 x 480
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window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
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if (!window)
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{
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glfwTerminate();
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return -1;
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}
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// Make the window to the current OpenGL context
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glfwMakeContextCurrent(window);
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// Loop until the window gets closed
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while (!glfwWindowShouldClose(window))
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{
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// Clear Screen with default color black
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glClear(GL_COLOR_BUFFER_BIT);
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// Render triangle
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glBegin(GL_TRIANGLES);
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// Left Down
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glColor3f(1.0f,0.0,0.0f);
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glVertex2f(-0.5f,-0.5f);
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// Right Down
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glColor3f(0.0f,1.0,0.0f);
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glVertex2f( 0.5f,-0.5f);
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// Mid Up
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glColor3f(0.0f,0.0f,1.0f);
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glVertex2f( 0.0f, 0.5f);
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glEnd();
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// Swap Buffers to render the new frame to the window
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glfwSwapBuffers(window);
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// Poll events to get the window close event
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glfwPollEvents();
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}
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// Terminate GLFW
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glfwTerminate();
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return 0;
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}
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```
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This code renders a triangle to a black window. To build this example you need the library [GLFW](https://www.glfw.org). <br>
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```
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sudo apt-get install libglfw3-dev
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```
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To build it just run <br>
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```
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gcc -o hello_world source.c -lglfw -lGL
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```
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