From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 25 Jan 2022 17:56:39 +0000 (+0200)
Subject: Use a dummy transmittance lookup texture to render the lookup in Sky
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=5ced451549e2238bb1195d03419437a395b9afec

Use a dummy transmittance lookup texture to render the lookup in Sky

Ideally the compiler should optimize the shader so the texture isn't
used, but that'll take some extra effort to implement.
---

diff --git a/source/effects/sky.cpp b/source/effects/sky.cpp
index eef6a58c..2732b7ad 100644
--- a/source/effects/sky.cpp
+++ b/source/effects/sky.cpp
@@ -25,6 +25,7 @@ Sky::Sky(Renderable &c, DirectionalLight &s):
 	backdrop_shprog(Resources::get_global().get<Program>("_sky_backdrop.glsl.shader")),
 	sampler(Resources::get_global().get<Sampler>("_linear_clamp.samp")),
 	wrap_sampler(Resources::get_global().get<Sampler>("_linear_clamp_v.samp")),
+	dummy_texture(Resources::get_global().get<Texture>("_placeholder.png")),
 	rendered(false)
 {
 	shdata.uniform("n_steps", 50);
@@ -112,6 +113,7 @@ void Sky::setup_frame(Renderer &renderer)
 			renderer.set_pipeline_key(this);
 			renderer.set_framebuffer(&transmittance_lookup.get_framebuffer());
 			renderer.set_shader_program(&transmittance_shprog);
+			renderer.set_texture("transmittance_lookup", &dummy_texture, &sampler);
 			fullscreen_mesh.draw(renderer);
 		}
 
diff --git a/source/effects/sky.h b/source/effects/sky.h
index 7d8933d4..cb8403e7 100644
--- a/source/effects/sky.h
+++ b/source/effects/sky.h
@@ -74,6 +74,7 @@ private:
 	const Program &backdrop_shprog;
 	const Sampler &sampler;
 	const Sampler &wrap_sampler;
+	const Texture &dummy_texture;
 	mutable ProgramData shdata;
 	float view_height;
 	bool rendered;