🚚 Move shader code to GLSL files

resources/shaders/tv.glsl

@@ -0,0 +1,42 @@
+float progress = uForOpening ? 1.0 - uProgress : uProgress;
+
+// 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(progress / TB_TIME, 0, 1));
+float lrProgress = smoothstep(0, 1, clamp((progress - LR_DELAY) / LR_TIME, 0, 1));
+float ffProgress = smoothstep(0, 1, clamp((progress - 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;
+
+cogl_color_out = texture2D(uTexture, cogl_tex_coord_in[0].st);
+
+// Shell.GLSLEffect uses straight alpha. So we have to convert from premultiplied.
+if (cogl_color_out.a > 0) {
+  cogl_color_out.rgb /= cogl_color_out.a;
+}
+
+cogl_color_out.rgb =
+  mix(cogl_color_out.rgb, uColor* cogl_color_out.a, smoothstep(0, 1, progress));
+cogl_color_out.a *= mask;
+
+// These are pretty useful for understanding how this works.
+// cogl_color_out = vec4(vec3(tbMask), 1);
+// cogl_color_out = vec4(vec3(lrMask), 1);
+// cogl_color_out = vec4(vec3(ffMask), 1);
+// cogl_color_out = vec4(vec3(mask), 1);