Merge Dockerfiles and use build arg instead

Dockerfile

@@ -2,13 +2,23 @@ FROM devkitpro/devkita64:20260215
 
 SHELL ["/bin/bash", "-c"]
 
+ARG GIMP_VERSION=2
+
 # Build tools + GIMP (for BCn texture conversion)
-RUN apt-get update && apt-get install -y --no-install-recommends \
+RUN if [ "$GIMP_VERSION" = "3" ]; then \
+        echo 'deb http://deb.debian.org/debian trixie main' > /etc/apt/sources.list.d/trixie.list \
+        && printf 'Package: *\nPin: release n=trixie\nPin-Priority: 100\n' > /etc/apt/preferences.d/trixie; \
+    fi \
+    && apt-get update && apt-get install -y --no-install-recommends \
     autoconf automake libtool \
     bison flex \
-    python3-pip python3-mako ninja-build \
+    python3-pip ninja-build \
     wget ca-certificates \
-    gimp \
+    && if [ "$GIMP_VERSION" = "3" ]; then \
+        apt-get install -y -t trixie --no-install-recommends gimp python3-mako; \
+    else \
+        apt-get install -y --no-install-recommends gimp python3-mako; \
+    fi \
     && pip3 install --break-system-packages meson \
     && rm -rf /var/lib/apt/lists/*
 

README.md

@@ -40,10 +40,9 @@ A hardware-accelerated media player for the Nintendo Switch, built on mpv and FF
 ```
 This builds the toolchain image and compiles everything automatically. Output will be found in `build/`.
 
-To test with GIMP 3 instead of the default GIMP 2, use `Dockerfile.gimp3`:
+To build with GIMP 3 instead of the default GIMP 2:
 ```sh
-docker build -f Dockerfile.gimp3 -t switchwave-builder .
-./build-docker.sh
+GIMP_VERSION=3 ./build-docker.sh
 ```
 
 ### Manual

build-docker.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -eo pipefail
 
-docker build  -t switchwave-builder .
+docker build --build-arg GIMP_VERSION="${GIMP_VERSION:-2}" -t switchwave-builder .
 
 docker run --rm --name devkitpro-switchwave \
     -v "$(pwd)":/mnt/ \