From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 14 Jun 2019 20:25:52 +0000 (+0300)
Subject: Add a vignette postprocessor
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=1e3954a988c6d6d946260019f25a4ad3262e01c4;p=libs%2Fdemoscene.git

Add a vignette postprocessor

All real cameras have some amount of vignetting, so adding some to the
rendered scene makes it feel more real.
---

diff --git a/data/vignette.glsl b/data/vignette.glsl
new file mode 100644
index 0000000..58822c4
--- /dev/null
+++ b/data/vignette.glsl
@@ -0,0 +1,32 @@
+import postprocess;
+
+uniform Vignette
+{
+	vec2 coord_scale;
+	vec4 optical;
+	vec2 optical_range;
+	float natural;
+};
+
+#pragma MSP stage(fragment)
+void main()
+{
+	vec4 incoming = texture(source, texcoord);
+	vec2 r = vertex.xy*coord_scale;
+	float r_sq = dot(r, r);
+
+	float vignette = 1.0;
+	if(r_sq>=optical_range.y)
+		vignette = 0.0;
+	else if(r_sq>=optical_range.x)
+	{
+		float r = sqrt(r_sq)-optical.x;
+		float v = (optical.z*acos(r/optical.y)-sqrt(optical.z-r*r)*r);
+		vignette = v/optical.w;
+	}
+
+	float c_sq = 1/(1+r_sq*natural);
+	vignette *= c_sq*c_sq;
+
+	frag_color = vec4(incoming.rgb*vignette, incoming.a);
+}
diff --git a/source/launcher.cpp b/source/launcher.cpp
index bad077d..7dc9b98 100644
--- a/source/launcher.cpp
+++ b/source/launcher.cpp
@@ -1,5 +1,6 @@
 #include <cmath>
 #include <msp/core/getopt.h>
+#include <msp/gl/pipelinetemplate.h>
 #include <msp/input/keys.h>
 #include <msp/io/console.h>
 #include <msp/io/file.h>
@@ -8,6 +9,7 @@
 #include "demo.h"
 #include "launcher.h"
 #include "launchscreen.h"
+#include "vignette.h"
 
 using namespace std;
 
@@ -102,6 +104,8 @@ LauncherBase::LauncherBase(int argc, char **argv):
 	gl_context.set_swap_interval(options.no_vsync ? 0 : 1);
 	window.signal_close.connect(sigc::bind(sigc::mem_fun(this, &LauncherBase::exit), 0));
 	keyboard.signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &LauncherBase::key_press), false));
+
+	GL::PipelineTemplate::register_postprocessor<Vignette>("vignette");
 }
 
 LauncherBase::~LauncherBase()
diff --git a/source/vignette.cpp b/source/vignette.cpp
new file mode 100644
index 0000000..e4d7de8
--- /dev/null
+++ b/source/vignette.cpp
@@ -0,0 +1,76 @@
+#include <algorithm>
+#include <msp/gl/mesh.h>
+#include <msp/gl/renderer.h>
+#include <msp/gl/texture2d.h>
+#include "resources.h"
+#include "vignette.h"
+
+using namespace std;
+
+namespace Msp {
+namespace DemoScene {
+
+Vignette::Vignette(float aspect):
+	mesh(get_fullscreen_quad()),
+	shprog(Resources::get_builtins().get<GL::Program>("vignette.glsl"))
+{
+	shdata.uniform("coord_scale", min(aspect, 1.0f), min(1.0f/aspect, 1.0f));
+	set_optical(1.0f, 0.5f);
+	set_natural(1.0f, 1.0f);
+}
+
+void Vignette::set_optical(float pupil, float aperture)
+{
+	if(pupil<0.0f || aperture<0.0f || aperture>pupil)
+		throw std::invalid_argument("Vignette::set_optical");
+
+	float p_sq = pupil*pupil;
+	float a_sq = aperture*aperture;
+	float two_ap = 2*pupil*aperture;
+	shdata.uniform("optical", pupil, aperture, a_sq, a_sq*M_PI);
+	shdata.uniform("optical_range", p_sq-two_ap+a_sq, p_sq+two_ap+a_sq);
+}
+
+void Vignette::set_natural(float radius, float darkening)
+{
+	if(radius<=0.0f || darkening<0.0f)
+		throw std::invalid_argument("Vignette::set_natural");
+
+	float v = pow(2.0f, -darkening);
+	float t_sq = 1/sqrt(v)-1;
+	shdata.uniform("natural", t_sq/(radius*radius));
+}
+
+void Vignette::render(GL::Renderer &renderer, const GL::Texture2D &color, const GL::Texture2D &)
+{
+	renderer.set_texture(&color);
+	renderer.set_shader_program(&shprog, &shdata);
+	mesh.draw(renderer);
+}
+
+
+Vignette::Template::Template():
+	pupil(1.0f),
+	aperture(0.5f),
+	radius(1.0f),
+	darkening(1.0f)
+{ }
+
+Vignette *Vignette::Template::create(unsigned w, unsigned h) const
+{
+	Vignette *vign = new Vignette(static_cast<float>(w)/h);
+	vign->set_optical(pupil, aperture);
+	vign->set_natural(radius, darkening);
+	return vign;
+}
+
+
+Vignette::Template::Loader::Loader(Template &t):
+	DerivedObjectLoader<Template, PostProcessor::Template::Loader>(t)
+{
+	add("optical", &Template::pupil, &Template::aperture);
+	add("natural", &Template::radius, &Template::darkening);
+}
+
+} // namespace DemoScene
+} // namespace Msp
diff --git a/source/vignette.h b/source/vignette.h
new file mode 100644
index 0000000..0cad6bf
--- /dev/null
+++ b/source/vignette.h
@@ -0,0 +1,52 @@
+#ifndef MSP_DEMOSCENE_VIGNETTE_H_
+#define MSP_DEMOSCENE_VIGNETTE_H_
+
+#include <msp/gl/postprocessor.h>
+#include <msp/gl/program.h>
+#include <msp/gl/programdata.h>
+
+namespace Msp {
+namespace DemoScene {
+
+class Vignette: public Msp::GL::PostProcessor
+{
+public:
+	struct Template: PostProcessor::Template
+	{
+		class Loader: public Msp::DataFile::DerivedObjectLoader<Template, PostProcessor::Template::Loader>
+		{
+		public:
+			Loader(Template &);
+		};
+
+		float pupil;
+		float aperture;
+		float radius;
+		float darkening;
+
+		Template();
+
+		virtual Vignette *create(unsigned, unsigned) const;
+	};
+
+private:
+	const Msp::GL::Mesh &mesh;
+	const Msp::GL::Program &shprog;
+	Msp::GL::ProgramData shdata;
+
+public:
+	Vignette(float);
+
+	void set_optical(float, float);
+	void set_natural(float, float);
+private:
+	void update_shdata();
+
+public:
+	virtual void render(Msp::GL::Renderer &, const Msp::GL::Texture2D &, const Msp::GL::Texture2D &);
+};
+
+} // namespace DemoScene
+} // namespace Msp
+
+#endif