[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, 60 insertions, 0 deletions

diff --git a/render/fx_renderer/gles2/shaders/blur_effects.frag b/render/fx_renderer/gles2/shaders/blur_effects.frag
new file mode 100644
index 0000000..fcead5d
--- /dev/null
+++ b/render/fx_renderer/gles2/shaders/blur_effects.frag
@@ -0,0 +1,60 @@
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+precision highp float;
+#else
+precision mediump float;
+#endif
+
+varying vec2 v_texcoord;
+
+uniform sampler2D tex;
+
+uniform float noise;
+uniform float brightness;
+uniform float contrast;
+uniform float saturation;
+
+mat4 brightnessMatrix() {
+	float b = brightness - 1.0;
+	return mat4(1, 0, 0, 0,
+				0, 1, 0, 0,
+				0, 0, 1, 0,
+				b, b, b, 1);
+}
+
+mat4 contrastMatrix() {
+	float t = (1.0 - contrast) / 2.0;
+	return mat4(contrast, 0, 0, 0,
+				0, contrast, 0, 0,
+				0, 0, contrast, 0,
+				t, t, t, 1);
+}
+
+mat4 saturationMatrix() {
+	vec3 luminance = vec3(0.3086, 0.6094, 0.0820);
+	float oneMinusSat = 1.0 - saturation;
+	vec3 red = vec3(luminance.x * oneMinusSat);
+	red+= vec3(saturation, 0, 0);
+	vec3 green = vec3(luminance.y * oneMinusSat);
+	green += vec3(0, saturation, 0);
+	vec3 blue = vec3(luminance.z * oneMinusSat);
+	blue += vec3(0, 0, saturation);
+	return mat4(red, 0,
+				green, 0,
+				blue, 0,
+				0, 0, 0, 1);
+}
+
+// Fast generative noise function
+float hash(vec2 p) {
+	return fract(sin(dot(p, vec2(12.9898, 78.233))) * 43758.5453);
+}
+
+void main() {
+	vec4 color = texture2D(tex, v_texcoord);
+	color *= brightnessMatrix() * contrastMatrix() * saturationMatrix();
+	float noiseHash = hash(v_texcoord);
+	float noiseAmount = (mod(noiseHash, 1.0) - 0.5);
+	color.rgb += noiseAmount * noise;
+
+	gl_FragColor = color;
+}