render/gles2: move shaders to individual files

Instead of having a C file with strings for each shader, move each
shader into its own file. Use a small POSIX shell script to convert
the files into C strings (can't wait for C23 #embed...).

The benefits from this are:

- Improved readability and syntax highlighting.
- Line numbers in shader compiler errors are easier to make sense of.
- Consistency with the Vulkan renderer.
- Shaders will become more complicated as we add color management
  features.

1 files changed, 8 insertions, 0 deletions

diff --git a/render/gles2/shaders/tex_rgba.frag b/render/gles2/shaders/tex_rgba.frag
new file mode 100644
index 00000000..c2e17a90
--- /dev/null
+++ b/render/gles2/shaders/tex_rgba.frag
@@ -0,0 +1,8 @@
+precision mediump float;
+varying vec2 v_texcoord;
+uniform sampler2D tex;
+uniform float alpha;
+
+void main() {
+	gl_FragColor = texture2D(tex, v_texcoord) * alpha;
+}