gfx/blur/box-linear: Refactor Linear Box Blur

Box Blur is a prime candidate for Linear optimizations, and as such reducing the total necessary samples by about half. However due to the reduction in samples, only Area and Directional Blur are supported.

Related: #45, #6

data/effects/blur/box-linear.effect

@@ -0,0 +1,122 @@
+// Parameters:
+/// OBS Default
+uniform float4x4 ViewProj;
+/// Texture
+uniform texture2d pImage;
+uniform float2 pImageTexel;
+/// Blur
+uniform float pSize;
+uniform float pSizeInverseMul;
+uniform float pAngle; 
+uniform float2 pCenter;
+uniform float2 pStepScale;
+
+#define MAX_BLUR_SIZE 128
+
+// # Linear Optimization
+// While the normal way is to sample every texel in the pSize, linear optimization
+//  takes advantage of the fact that most people, especially after compression,
+//  will not be able to tell the difference between a linear approximation and
+//  the actual thing.
+//
+// Instead of sampling every texel like this:
+// 
+//       |Tx|Tx|Tx|Tx|Tx|
+//     Tx|-2|-1| 0|+1|+2|
+// 
+// Linear optimization will sample like this:
+// 
+//       |Tx|Tx|Tx|Tx|Tx|
+//     Tx| -1  | 0|  +1 |
+//
+// This effectively removes half the necessary samples and looks identical when
+//  when used with box blur. However there is an edge case when the blur width
+//  is not a multiple of two, where two additional samples have to be spent on
+//  reading the outer edge:
+// 
+//       |Tx|Tx|Tx|Tx|Tx|Tx|Tx|
+//     Tx|-2| -1  | 0|  +1 |+2|
+//
+// or this alternative pattern that uses two less samples:
+// 
+//       |Tx|Tx|Tx|Tx|Tx|Tx|Tx|
+//     Tx|  0  |  +1 |  +2 |+3|
+//
+// With careful planning this can even be used for other types of Blur, such as
+//  Gaussian Blur, which suffers a larger hit - however there are better and
+//  faster alternatives than linear sampling with Gaussian Blur, such as
+//  Dual Filtering ("Dual Kawase").
+
+// Sampler
+sampler_state linearSampler {
+	Filter    = Linear;
+	AddressU  = Clamp;
+	AddressV  = Clamp;
+	MinLOD    = 0;
+	MaxLOD    = 0;
+};
+
+// Default Vertex Shader and Data
+struct VertDataIn {
+	float4 pos : POSITION;
+	float2 uv  : TEXCOORD0;
+};
+
+struct VertDataOut {
+	float4 pos  : POSITION;
+	float2 uv   : TEXCOORD0;
+	bool is_odd : TEXCOORD1;
+};
+
+VertDataOut VSDefault(VertDataIn vtx) {
+	VertDataOut vert_out;
+	vert_out.pos = mul(float4(vtx.pos.xyz, 1.0), ViewProj);
+	vert_out.uv  = vtx.uv;
+	vert_out.is_odd = ((int(round(pSize)) % 2) == 1);
+	return vert_out;
+}
+
+// Blur 1 Dimensional
+float4 PSBlur1D(VertDataOut vtx) : TARGET {
+	float4 final = pImage.Sample(linearSampler, vtx.uv);
+
+	// y = yes, s = skip, b = break
+	// Size-> | 1| 2| 3| 4| 5| 6| 7|
+	// -------+--+--+--+--+--+--+--+
+	// n=1    | b| y| y| y| y| y| y|
+	// n=2    |  |bs| s| s| s| s| s|
+	// n=3    |  | b| b| y| y| y| y|
+	// n=4    |  |  |  |bs| s| s| s|
+	// n=5    |  |  |  | b| b| y| y|
+	// n=6    |  |  |  |  |  |bs| s|
+	// n=7    |  |  |  |  |  | b| b|
+	// n=8    |  |  |  |  |  |  |  |
+
+	// Loop unrolling is only possible with a fixed known maximum.
+	// Some compilers may unroll up to x iterations, but most will not.
+	for (int n = 1; n <= MAX_BLUR_SIZE; n+=2) {
+		// Different from normal box, early exit instead of late exit.
+		if (n >= pSize) {
+			break;
+		}
+
+		float2 nstep = (pImageTexel * pStepScale) * (n + 0.5);
+		final += pImage.Sample(linearSampler, vtx.uv + nstep) * 2.;
+		final += pImage.Sample(linearSampler, vtx.uv - nstep) * 2.;
+	}
+	if (vtx.is_odd) {
+		float2 nstep = (pImageTexel * pStepScale) * pSize;
+		final += pImage.Sample(linearSampler, vtx.uv + nstep);
+		final += pImage.Sample(linearSampler, vtx.uv - nstep);
+	}
+
+	final *= pSizeInverseMul;
+	return final;
+}
+
+technique Draw {
+	pass {
+		vertex_shader = VSDefault(vtx);
+		pixel_shader  = PSBlur1D(vtx);
+	}
+}

source/gfx/blur/gfx-blur-box-linear.cpp

@@ -0,0 +1,363 @@
+// Modern effects for a modern Streamer
+// Copyright (C) 2019 Michael Fabian Dirks
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+
+#include "gfx-blur-box-linear.hpp"
+#include <cmath>
+#include <memory>
+#include "plugin.hpp"
+#include "util-math.hpp"
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4201)
+#endif
+#include <obs-module.h>
+#include <obs.h>
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+#define MAX_BLUR_SIZE 128 // Also change this in box-linear.effect if modified.
+
+gfx::blur::box_linear_data::box_linear_data()
+{
+	try {
+		char* file = obs_module_file("effects/blur/box-linear.effect");
+		m_effect   = std::make_shared<::gs::effect>(file);
+		bfree(file);
+	} catch (...) {
+		P_LOG_ERROR("<gfx::blur::box_linear> Failed to load effect.");
+	}
+}
+
+gfx::blur::box_linear_data::~box_linear_data()
+{
+	m_effect.reset();
+}
+
+std::shared_ptr<::gs::effect> gfx::blur::box_linear_data::get_effect()
+{
+	return m_effect;
+}
+
+gfx::blur::box_linear_factory::box_linear_factory() {}
+
+gfx::blur::box_linear_factory::~box_linear_factory() {}
+
+bool gfx::blur::box_linear_factory::is_type_supported(::gfx::blur::type type)
+{
+	switch (type) {
+	case ::gfx::blur::type::Area:
+		return true;
+	case ::gfx::blur::type::Directional:
+		return true;
+	default:
+		return false;
+	}
+}
+
+std::shared_ptr<::gfx::blur::ibase> gfx::blur::box_linear_factory::create(::gfx::blur::type type)
+{
+	switch (type) {
+	case ::gfx::blur::type::Area:
+		return std::make_shared<::gfx::blur::box_linear>();
+	case ::gfx::blur::type::Directional:
+		return std::make_shared<::gfx::blur::box_linear_directional>();
+	default:
+		throw std::runtime_error("Invalid type.");
+	}
+}
+
+double_t gfx::blur::box_linear_factory::get_min_size(::gfx::blur::type)
+{
+	return double_t(1.0);
+}
+
+double_t gfx::blur::box_linear_factory::get_step_size(::gfx::blur::type)
+{
+	return double_t(1.0);
+}
+
+double_t gfx::blur::box_linear_factory::get_max_size(::gfx::blur::type)
+{
+	return double_t(MAX_BLUR_SIZE);
+}
+
+double_t gfx::blur::box_linear_factory::get_min_angle(::gfx::blur::type v)
+{
+	switch (v) {
+	case ::gfx::blur::type::Directional:
+	case ::gfx::blur::type::Rotational:
+		return -180.0;
+	default:
+		return 0;
+	}
+}
+
+double_t gfx::blur::box_linear_factory::get_step_angle(::gfx::blur::type)
+{
+	return double_t(0.01);
+}
+
+double_t gfx::blur::box_linear_factory::get_max_angle(::gfx::blur::type v)
+{
+	switch (v) {
+	case ::gfx::blur::type::Directional:
+	case ::gfx::blur::type::Rotational:
+		return 180.0;
+	default:
+		return 0;
+	}
+}
+
+bool gfx::blur::box_linear_factory::is_step_scale_supported(::gfx::blur::type v)
+{
+	switch (v) {
+	case ::gfx::blur::type::Area:
+	case ::gfx::blur::type::Zoom:
+	case ::gfx::blur::type::Directional:
+		return true;
+	default:
+		return false;
+	}
+}
+
+double_t gfx::blur::box_linear_factory::get_min_step_scale_x(::gfx::blur::type)
+{
+	return double_t(0.01);
+}
+
+double_t gfx::blur::box_linear_factory::get_step_step_scale_x(::gfx::blur::type)
+{
+	return double_t(0.01);
+}
+
+double_t gfx::blur::box_linear_factory::get_max_step_scale_x(::gfx::blur::type)
+{
+	return double_t(1000.0);
+}
+
+double_t gfx::blur::box_linear_factory::get_min_step_scale_y(::gfx::blur::type)
+{
+	return double_t(0.01);
+}
+
+double_t gfx::blur::box_linear_factory::get_step_step_scale_y(::gfx::blur::type)
+{
+	return double_t(0.01);
+}
+
+double_t gfx::blur::box_linear_factory::get_max_step_scale_y(::gfx::blur::type)
+{
+	return double_t(1000.0);
+}
+
+std::shared_ptr<::gfx::blur::box_linear_data> gfx::blur::box_linear_factory::data()
+{
+	std::unique_lock<std::mutex>           ulock(m_data_lock);
+	std::shared_ptr<::gfx::blur::box_linear_data> data = m_data.lock();
+	if (!data) {
+		data   = std::make_shared<::gfx::blur::box_linear_data>();
+		m_data = data;
+	}
+	return data;
+}
+
+::gfx::blur::box_linear_factory& gfx::blur::box_linear_factory::get()
+{
+	static ::gfx::blur::box_linear_factory instance;
+	return instance;
+}
+
+gfx::blur::box_linear::box_linear() : m_size(1.), m_step_scale({1., 1.}), m_data(::gfx::blur::box_linear_factory::get().data())
+{
+	m_rendertarget  = std::make_shared<::gs::rendertarget>(GS_RGBA, GS_ZS_NONE);
+	m_rendertarget2 = std::make_shared<::gs::rendertarget>(GS_RGBA, GS_ZS_NONE);
+}
+
+gfx::blur::box_linear::~box_linear() {}
+
+void gfx::blur::box_linear::set_input(std::shared_ptr<::gs::texture> texture)
+{
+	m_input_texture = texture;
+}
+
+::gfx::blur::type gfx::blur::box_linear::get_type()
+{
+	return ::gfx::blur::type::Area;
+}
+
+double_t gfx::blur::box_linear::get_size()
+{
+	return m_size;
+}
+
+void gfx::blur::box_linear::set_size(double_t width)
+{
+	m_size = width;
+	if (m_size < 1.0) {
+		m_size = 1.0;
+	}
+	if (m_size > MAX_BLUR_SIZE) {
+		m_size = MAX_BLUR_SIZE;
+	}
+}
+
+void gfx::blur::box_linear::set_step_scale(double_t x, double_t y)
+{
+	m_step_scale = {x, y};
+}
+
+void gfx::blur::box_linear::get_step_scale(double_t& x, double_t& y)
+{
+	x = m_step_scale.first;
+	y = m_step_scale.second;
+}
+
+double_t gfx::blur::box_linear::get_step_scale_x()
+{
+	return m_step_scale.first;
+}
+
+double_t gfx::blur::box_linear::get_step_scale_y()
+{
+	return m_step_scale.second;
+}
+
+std::shared_ptr<::gs::texture> gfx::blur::box_linear::render()
+{
+	float_t width, height;
+	width  = float_t(m_input_texture->get_width());
+	height = float_t(m_input_texture->get_height());
+
+	obs_enter_graphics();
+	gs_set_cull_mode(GS_NEITHER);
+	gs_enable_color(true, true, true, true);
+	gs_enable_depth_test(false);
+	gs_depth_function(GS_ALWAYS);
+	gs_blend_state_push();
+	gs_reset_blend_state();
+	gs_enable_blending(false);
+	gs_blend_function(GS_BLEND_ONE, GS_BLEND_ZERO);
+	gs_enable_stencil_test(false);
+	gs_enable_stencil_write(false);
+	gs_stencil_function(GS_STENCIL_BOTH, GS_ALWAYS);
+	gs_stencil_op(GS_STENCIL_BOTH, GS_ZERO, GS_ZERO, GS_ZERO);
+
+	// Two Pass Blur
+	std::shared_ptr<::gs::effect> effect = m_data->get_effect();
+	if (effect) {
+		// Pass 1
+		effect->get_parameter("pImage").set_texture(m_input_texture);
+		effect->get_parameter("pImageTexel").set_float2(float_t(1. / width), 0.);
+		effect->get_parameter("pStepScale").set_float2(float_t(m_step_scale.first), float_t(m_step_scale.second));
+		effect->get_parameter("pSize").set_float(float_t(m_size));
+		effect->get_parameter("pSizeInverseMul").set_float(float_t(1.0 / (float_t(m_size) * 2.0 + 1.0)));
+
+		{
+			auto op = m_rendertarget2->render(uint32_t(width), uint32_t(height));
+			gs_ortho(0, 1., 0, 1., 0, 1.);
+			while (gs_effect_loop(effect->get_object(), "Draw")) {
+				gs_draw_sprite(0, 0, 1, 1);
+			}
+		}
+
+		// Pass 2
+		effect->get_parameter("pImage").set_texture(m_rendertarget2->get_texture());
+		effect->get_parameter("pImageTexel").set_float2(0., float_t(1. / height));
+
+		{
+			auto op = m_rendertarget->render(uint32_t(width), uint32_t(height));
+			gs_ortho(0, 1., 0, 1., 0, 1.);
+			while (gs_effect_loop(effect->get_object(), "Draw")) {
+				gs_draw_sprite(0, 0, 1, 1);
+			}
+		}
+	}
+
+	gs_blend_state_pop();
+	obs_leave_graphics();
+
+	return m_rendertarget->get_texture();
+}
+
+std::shared_ptr<::gs::texture> gfx::blur::box_linear::get()
+{
+	return m_rendertarget->get_texture();
+}
+
+gfx::blur::box_linear_directional::box_linear_directional() : m_angle(0) {}
+
+::gfx::blur::type gfx::blur::box_linear_directional::get_type()
+{
+	return ::gfx::blur::type::Directional;
+}
+
+double_t gfx::blur::box_linear_directional::get_angle()
+{
+	return RAD_TO_DEG(m_angle);
+}
+
+void gfx::blur::box_linear_directional::set_angle(double_t angle)
+{
+	m_angle = DEG_TO_RAD(angle);
+}
+
+std::shared_ptr<::gs::texture> gfx::blur::box_linear_directional::render()
+{
+	float_t width, height;
+	width  = float_t(m_input_texture->get_width());
+	height = float_t(m_input_texture->get_height());
+
+	obs_enter_graphics();
+	gs_blend_state_push();
+	gs_reset_blend_state();
+	gs_enable_color(true, true, true, true);
+	gs_enable_blending(false);
+	gs_enable_depth_test(false);
+	gs_enable_stencil_test(false);
+	gs_enable_stencil_write(false);
+	gs_set_cull_mode(GS_NEITHER);
+	gs_depth_function(GS_ALWAYS);
+	gs_blend_function(GS_BLEND_ONE, GS_BLEND_ZERO);
+	gs_stencil_function(GS_STENCIL_BOTH, GS_ALWAYS);
+	gs_stencil_op(GS_STENCIL_BOTH, GS_ZERO, GS_ZERO, GS_ZERO);
+
+	// One Pass Blur
+	std::shared_ptr<::gs::effect> effect = m_data->get_effect();
+	if (effect) {
+		effect->get_parameter("pImage").set_texture(m_input_texture);
+		effect->get_parameter("pImageTexel")
+			.set_float2(float_t(1. / width * cos(m_angle)), float_t(1. / height * sin(m_angle)));
+		effect->get_parameter("pStepScale").set_float2(float_t(m_step_scale.first), float_t(m_step_scale.second));
+		effect->get_parameter("pSize").set_float(float_t(m_size));
+		effect->get_parameter("pSizeInverseMul").set_float(float_t(1.0 / (float_t(m_size) * 2.0 + 1.0)));
+
+		{
+			auto op = m_rendertarget->render(uint32_t(width), uint32_t(height));
+			gs_ortho(0, 1., 0, 1., 0, 1.);
+			while (gs_effect_loop(effect->get_object(), "Draw")) {
+				gs_draw_sprite(0, 0, 1, 1);
+			}
+		}
+	}
+
+	gs_blend_state_pop();
+	obs_leave_graphics();
+
+	return m_rendertarget->get_texture();
+}

source/gfx/blur/gfx-blur-box-linear.hpp

@@ -0,0 +1,129 @@
+// Modern effects for a modern Streamer
+// Copyright (C) 2019 Michael Fabian Dirks
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+
+#pragma once
+#include <cinttypes>
+#include <memory>
+#include <mutex>
+#include "gfx-blur-base.hpp"
+#include "obs/gs/gs-effect.hpp"
+#include "obs/gs/gs-rendertarget.hpp"
+#include "obs/gs/gs-texture.hpp"
+
+namespace gfx {
+	namespace blur {
+		class box_linear_data {
+			std::shared_ptr<::gs::effect> m_effect;
+
+			public:
+			box_linear_data();
+			~box_linear_data();
+
+			std::shared_ptr<::gs::effect> get_effect();
+		};
+
+		class box_linear_factory : public ::gfx::blur::ifactory {
+			std::mutex                           m_data_lock;
+			std::weak_ptr<::gfx::blur::box_linear_data> m_data;
+
+			public:
+			box_linear_factory();
+			virtual ~box_linear_factory();
+
+			virtual bool is_type_supported(::gfx::blur::type type) override;
+
+			virtual std::shared_ptr<::gfx::blur::ibase> create(::gfx::blur::type type) override;
+
+			virtual double_t get_min_size(::gfx::blur::type type) override;
+
+			virtual double_t get_step_size(::gfx::blur::type type) override;
+
+			virtual double_t get_max_size(::gfx::blur::type type) override;
+
+			virtual double_t get_min_angle(::gfx::blur::type type) override;
+
+			virtual double_t get_step_angle(::gfx::blur::type type) override;
+
+			virtual double_t get_max_angle(::gfx::blur::type type) override;
+
+			virtual bool is_step_scale_supported(::gfx::blur::type type) override;
+
+			virtual double_t get_min_step_scale_x(::gfx::blur::type type) override;
+
+			virtual double_t get_step_step_scale_x(::gfx::blur::type type) override;
+
+			virtual double_t get_max_step_scale_x(::gfx::blur::type type) override;
+
+			virtual double_t get_min_step_scale_y(::gfx::blur::type type) override;
+
+			virtual double_t get_step_step_scale_y(::gfx::blur::type type) override;
+
+			virtual double_t get_max_step_scale_y(::gfx::blur::type type) override;
+
+			std::shared_ptr<::gfx::blur::box_linear_data> data();
+
+			public: // Singleton
+			static ::gfx::blur::box_linear_factory& get();
+		};
+
+		class box_linear : public ::gfx::blur::ibase {
+			protected:
+			std::shared_ptr<::gfx::blur::box_linear_data> m_data;
+
+			double_t                            m_size;
+			std::pair<double_t, double_t>       m_step_scale;
+			std::shared_ptr<::gs::texture>      m_input_texture;
+			std::shared_ptr<::gs::rendertarget> m_rendertarget;
+
+			private:
+			std::shared_ptr<::gs::rendertarget> m_rendertarget2;
+
+			public:
+			box_linear();
+			~box_linear();
+
+			virtual void set_input(std::shared_ptr<::gs::texture> texture) override;
+
+			virtual ::gfx::blur::type get_type() override;
+
+			virtual double_t get_size() override;
+			virtual void     set_size(double_t width) override;
+
+			virtual void     set_step_scale(double_t x, double_t y) override;
+			virtual void     get_step_scale(double_t& x, double_t& y) override;
+			virtual double_t get_step_scale_x() override;
+			virtual double_t get_step_scale_y() override;
+
+			virtual std::shared_ptr<::gs::texture> render() override;
+			virtual std::shared_ptr<::gs::texture> get() override;
+		};
+
+		class box_linear_directional : public ::gfx::blur::box_linear, public ::gfx::blur::ibase_angle {
+			double_t m_angle;
+
+			public:
+			box_linear_directional();
+
+			virtual ::gfx::blur::type get_type() override;
+
+			virtual double_t get_angle() override;
+			virtual void     set_angle(double_t angle) override;
+
+			virtual std::shared_ptr<::gs::texture> render() override;
+		};
+	} // namespace blur
+} // namespace gfx