main.c File Reference

SNES mouse input with cursor sprite, buttons, and sensitivity. More...

#include <snes.h>
#include <snes/input.h>
#include <snes/text.h>
#include <snes/dma.h>
#include "res/cursor.inc"

Functions
int	main (void)
	Main entry point – mouse detection, initialization, and input loop.

Variables
static s16	pos_x
	Cursor sprite tile data (16x16, 4bpp) defined in data.asm.
static s16	pos_y
	Absolute cursor Y position on screen.
static const char	sens_hi [] = "HIGH"
	Sensitivity label: high speed (largest deltas per physical movement).
static const char	sens_low [] = "LOW "
	Sensitivity label: low speed (smallest deltas per physical movement).
static const char	sens_med [] = "MED "
	Sensitivity label: medium speed.

Detailed Description

SNES mouse input with cursor sprite, buttons, and sensitivity.

Demonstrates the SNES Mouse peripheral connected to controller port 1. The SNES mouse is a standard serial device that reports relative X/Y deltas and two buttons each frame via the auto-joypad read registers. This example accumulates the deltas into absolute screen coordinates and drives a 16x16 hardware sprite as a cursor.

The mouse supports three sensitivity levels (low, medium, high) that scale the delta values. Sensitivity is toggled by right-clicking. If no mouse is detected at startup, a diagnostic message is shown.

SNES Concepts

• Mouse peripheral detection and initialization via auto-joypad
• Relative-to-absolute coordinate accumulation from mouse deltas
• Sensitivity control (hardware-level scaling of mouse movement)
• Sprite used as a cursor overlay on a text background

What to Observe

• A 16x16 cursor sprite follows mouse movement on screen
• Left click changes the background color to blue
• Right click cycles sensitivity (LOW / MED / HIGH)
• Button states ("PRESSED") appear next to L-click / R-click labels
• Without a mouse connected, a "No mouse detected" message appears

Modules Used

console, input, sprite, dma, text, background

See also

input.h, sprite.h, dma.h, text.h

Function Documentation

main()

int main

(

void

)

Main entry point – mouse detection, initialization, and input loop.

Sets up Mode 0 with a text background for status display and a 16x16 hardware sprite as a mouse cursor. The mouse is detected via mouseInit() on port 1. If absent, the program halts with a diagnostic message. Otherwise, the main loop reads relative mouse deltas each frame, accumulates them into absolute screen coordinates, and updates the cursor sprite position and button/sensitivity status on screen.

Returns

0 (never reached – infinite game loop)

Variable Documentation

pos_x

s16 pos_x

static

Cursor sprite tile data (16x16, 4bpp) defined in data.asm.

Cursor sprite palette (SNES BGR555 format) defined in data.asm

Absolute cursor X position on screen.

Accumulated from relative mouse X deltas each frame. The SNES mouse reports displacement, not position, so we must integrate the deltas ourselves and clamp to the visible screen range (0-255).

pos_y

s16 pos_y

static

Absolute cursor Y position on screen.

Same accumulation strategy as pos_x, clamped to 0-223 (NTSC visible).

sens_hi

const char sens_hi[] = "HIGH"

static

Sensitivity label: high speed (largest deltas per physical movement).

sens_low

const char sens_low[] = "LOW "

static

Sensitivity label: low speed (smallest deltas per physical movement).

sens_med

const char sens_med[] = "MED "

static

Sensitivity label: medium speed.