From 0edaebe192839083528c856bd0d9e1bcab7a8006 Mon Sep 17 00:00:00 2001 From: Michael Fabian Dirks Date: Fri, 28 Oct 2016 21:16:04 +0200 Subject: [PATCH] obs-transitions: Avoid branching in slide_transition.effect Branching is not recommended in shaders and only recently gained widespread support without causing massive branch misprediction issues. Also sampling inside a branch will cause cache misses and additional texture load instructions. --- plugins/obs-transitions/data/slide_transition.effect | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/plugins/obs-transitions/data/slide_transition.effect b/plugins/obs-transitions/data/slide_transition.effect index 91a9b8952..413212c17 100644 --- a/plugins/obs-transitions/data/slide_transition.effect +++ b/plugins/obs-transitions/data/slide_transition.effect @@ -28,11 +28,12 @@ float4 PSSlide(VertData v_in) : TARGET { float2 tex_a_uv = v_in.uv + tex_a_dir; float2 tex_b_uv = v_in.uv - tex_b_dir; - - return (tex_a_uv.x - saturate(tex_a_uv.x) != 0.0) || - (tex_a_uv.y - saturate(tex_a_uv.y) != 0.0) - ? tex_b.Sample(textureSampler, tex_b_uv) - : tex_a.Sample(textureSampler, tex_a_uv); + + float4 tex_a_sample = tex_a.Sample(textureSampler, tex_a_uv); + float4 tex_b_sample = tex_b.Sample(textureSampler, tex_b_uv); + + float val = saturate(abs((tex_a_uv.x - saturate(tex_a_uv.x)) + (tex_a_uv.y - saturate(tex_a_uv.y))) * 65535); + return lerp(tex_a_sample, tex_b_sample, val); } technique Slide