From 03db97fdda4f5fae46630fcdcaa7e9342c98a13d Mon Sep 17 00:00:00 2001 From: Simon Schneegans Date: Fri, 31 Dec 2021 20:34:50 +0100 Subject: [PATCH] :memo: Add comments --- src/extension/TVEffectShader.js | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/src/extension/TVEffectShader.js b/src/extension/TVEffectShader.js index a949584..e27f82a 100644 --- a/src/extension/TVEffectShader.js +++ b/src/extension/TVEffectShader.js @@ -20,7 +20,9 @@ const Me = imports.misc.extensionUtils.getCurrentExtension(); const shaderSnippets = Me.imports.src.extension.shaderSnippets; ////////////////////////////////////////////////////////////////////////////////////////// -// The TVEffectShader ... // +// The TVEffectShader hides the actor by making it first transparent from top and // +// bottom towards the middle and then hiding the resulting line from left and right // +// towards the center. // ////////////////////////////////////////////////////////////////////////////////////////// var TVEffectShader = GObject.registerClass( @@ -33,28 +35,36 @@ var TVEffectShader = GObject.registerClass( // Inject some common shader snippets. ${shaderSnippets.standardUniforms()} - const float BLUR_WIDTH = 0.01; - const float TB_TIME = 0.7; - const float LR_TIME = 0.4; - const float LR_DELAY = 0.6; - const float FF_TIME = 0.2; + const float BLUR_WIDTH = 0.01; // Width of the gradients. + const float TB_TIME = 0.7; // Relative time for the top/bottom animation. + const float LR_TIME = 0.4; // Relative time for the left/right animation. + const float LR_DELAY = 0.6; // Delay after which the left/right animation starts. + const float FF_TIME = 0.2; // Relative time for the final fade to transparency. void main() { + // All of these are in [0..1] during the different stages of the animation. + // tb refers to the top-bottom animation. + // lr refers to the left-right animation. + // ff refers to the final fade animation. float tbProgress = smoothstep(0, 1, clamp(uProgress/TB_TIME, 0, 1)); float lrProgress = smoothstep(0, 1, clamp((uProgress - LR_DELAY)/LR_TIME, 0, 1)); float ffProgress = smoothstep(0, 1, clamp((uProgress - 1.0 + FF_TIME)/FF_TIME, 0, 1)); + // This is a top-center-bottom gradient in [0..1..0] float tb = cogl_tex_coord_in[0].t * 2; tb = tb < 1 ? tb : 2 - tb; + // This is a left-center-right gradient in [0..1..0] float lr = cogl_tex_coord_in[0].s * 2; lr = lr < 1 ? lr : 2 - lr; + // Combine the progress values with the gradients to create the alpha masks. float tbMask = 1 - smoothstep(0, 1, clamp((tbProgress - tb) / BLUR_WIDTH, 0, 1)); float lrMask = 1 - smoothstep(0, 1, clamp((lrProgress - lr) / BLUR_WIDTH, 0, 1)); float ffMask = 1 - smoothstep(0, 1, ffProgress); + // Assemble the final alpha value. float mask = tbMask * lrMask * ffMask; vec4 windowColor = texture2D(uTexture, cogl_tex_coord_in[0].st);