[FX Renderer] Add blur (#30)

* Initial blur implementation

* Added additional blur effects from SwayFX

* Simplified blur pass functions to match the other pass functions

* Minor fixes

* Added support for optimized blur

* tinywl: Don't set decoration values every frame

* Updated public blur function docs

* Simplified blur buffer management

* Moved ignore transparent bool into a per buffer option

* Clip the scene_buffer when blur is enabled

* Added back corner and shadow checks in opaque_region function

* Renamed fx_render_blur_options to fx_render_blur_pass_options

* Fixed nits

* Removed unused fx_framebuffer_bind_wlr_fbo function

* Removed wlr_scene impl. Should be moved into future PR instead

* Made blur impl independent of wlr_scene

* Moved shader init back into fx_renderer.c

* Renamed fx_framebuffer_get_or_create_bufferless to fx_framebuffer_get_or_create_custom

1 files changed, 18 insertions, 0 deletions

diff --git a/render/fx_renderer/gles2/shaders/blur1.frag b/render/fx_renderer/gles2/shaders/blur1.frag
new file mode 100644
index 0000000..e7cb1be
--- /dev/null
+++ b/render/fx_renderer/gles2/shaders/blur1.frag
@@ -0,0 +1,18 @@
+precision mediump float;
+varying mediump vec2 v_texcoord;
+uniform sampler2D tex;
+
+uniform float radius;
+uniform vec2 halfpixel;
+
+void main() {
+    vec2 uv = v_texcoord * 2.0;
+
+    vec4 sum = texture2D(tex, uv) * 4.0;
+    sum += texture2D(tex, uv - halfpixel.xy * radius);
+    sum += texture2D(tex, uv + halfpixel.xy * radius);
+    sum += texture2D(tex, uv + vec2(halfpixel.x, -halfpixel.y) * radius);
+    sum += texture2D(tex, uv - vec2(halfpixel.x, -halfpixel.y) * radius);
+
+    gl_FragColor = sum / 8.0;
+}