How To Draw a Pixel

Summary

In this video, the presenter demonstrates how to create a simple program using the SDL2 library in C++ to draw a single pixel on the screen. He explains the necessary includes, initializes the SDL library, and sets up the window and renderer with specified dimensions. The tutorial emphasizes configuring the draw color to black for clearing the screen and white for drawing the pixel at the center. Finally, he compiles and runs the program, showcasing the drawn pixel, and hints at extending the tutorial to include line drawing in the next section.

Takeaways

• 🖥️ SDL2 is a library for C and C++ that simplifies drawing graphics to the screen.
• 📐 To draw graphics, two structures need to be declared: SDL_Window and SDL_Renderer.
• 🔄 SDL must be initialized before using any drawing functions.
• 📏 The window dimensions are set by multiplying the width and height by 4 for high DPI screens.
• 🎨 The renderer's draw color is initially set to black to clear the screen.
• 🌈 The draw color is changed to white before drawing a point on the screen.
• 📍 The point is drawn at the center of the screen using the scaled coordinates.
• 👁️ The renderer is presented to show the drawing in the window.
• ⏳ A delay of 10 seconds is implemented to ensure the window stays open for viewing.
• 💻 The program is compiled using GCC on Linux with SDL2 linked.

Q & A

What library is being used for drawing graphics in this program?

The program uses the SDL2 library, which facilitates drawing graphics to the screen in C and C++.

What two structures are required to draw a pixel using SDL2?

The two required structures are SDL_Window and SDL_Renderer.

What is the purpose of initializing SDL before using drawing functions?

Initializing SDL is necessary because it prepares the library for use, ensuring all functions can operate correctly.

Why is the window size multiplied by four in the code?

The window size is multiplied by four to accommodate high DPI screens, making the pixel visible on such displays.

What color is set for the renderer before drawing?

The renderer's color is initially set to black to clear the renderer before any drawing occurs.

What color is used to draw the pixel, and why?

The pixel is drawn in white because the color needs to be visible against the black background.

How are the coordinates for the pixel's position determined?

The pixel's position is set to the center of the screen, calculated by dividing the window dimensions by two.

What does the function SDL_RenderPresent do?

SDL_RenderPresent displays the current rendering in the window, making the drawn graphics visible to the user.

Why is there a delay of 10,000 milliseconds in the program?

The delay ensures that the window remains open long enough for the user to see the drawn pixel before the program closes.

What will the next section of the tutorial cover after drawing a pixel?

The next section will transition from drawing a pixel to drawing a line.