98 lines
2.6 KiB
Markdown
98 lines
2.6 KiB
Markdown
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---
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title: 3DS Programming - Touchscreen Input
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description: A guide to using the touchscreen on the 3DS. (Old)
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date: 2025-01-01
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tags: ['3ds', 'programming', 'c', 'devkitpro', 'old']
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previous: old3ds_romfs.md
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---
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# Touchscreen Input
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> [!warning]
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> This guide of mine is old - Like 3 years old at the time of posting. I prefer to keep it up, but I don't think it very highly - It should still work though.
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> I might make a new one in the future.
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> I'm doing some alterations at least to make it more readable.
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> It doesn't teach why things are done very well is my primary issue with it.
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Here we will find the position of a touch on the touchscreen.
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It is very simple to do this.
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## Getting the touch position
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To find the touch position, we need to request the touchPosition type from the OS, and read from that.
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We must first create a touchPosition like so:
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```c
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// Check for input
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// ...
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// Will contain the position of the touch
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touchPosition touch;
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// Will obtain that information
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hidTouchRead(&touch);
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// Exit program if START is pressed
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// ...
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```
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Then, we must read from it like so:
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The touch position is stored in our touchPosition as 'px' and 'py'.
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## Printing the information to the screen
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To print the position so we may see it, we should, instead of spamming the console with it, overwrite the X and Y position output by setting the position of the output first.
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This would make it much easier to read, although we would need some whitespace after it to prevent anything getting printed without overwriting:
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```c
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// Print the touch screen coordinates
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// Keep the whitespace if you do not want issues
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printf("\x1b[1;0H X=%u Y=%u ", touch.px, touch.py);
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// Exit program if START is pressed
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// ...
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```
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The position should default to [0, 0] when no touch is found:
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## Wrapping up
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Our code should now look like this:
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```c
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#include <stdio.h>
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#include <3ds.h>
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int main() {
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// Initialize the console
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gfxInitDefault();
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consoleInit(GFX_BOTTOM, NULL);
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// Will contain the position of the touch
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// This can either be inside or outside the main loop
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touchPosition touch;
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while (aptMainLoop()) {
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// Check for input
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hidScanInput();
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// Will obtain that information
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hidTouchRead(&touch);
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// Print the touch screen coordinates
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// Keep the whitespace if you do not want issues
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printf("\x1b[1;0H X=%u Y=%u ", touch.px, touch.py);
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// Exit program if START is pressed
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if (hidKeysDown() & KEY_START)
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break;
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}
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return 0;
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}
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```
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