New Shader Image Processing

Cleanup shaders and add image processing shader for source
2025-12-13 11:19:58 +01:00 · 2020-04-25 23:58:49 +02:00
parent 0e24d1a083
commit 551acf25b9
24 changed files with 1009 additions and 65 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -202,6 +202,7 @@ set(VMIX_SRCS
    Log.cpp
    Shader.cpp
    ImageShader.cpp
+    ImageProcessingShader.cpp
    Scene.cpp
    Primitives.cpp
    Mesh.cpp
@@ -226,10 +227,11 @@ set(VMIX_SRCS
 )

 set(VMIX_RSC_FILES
-    ./rsc/shaders/simple-shader.fs
-    ./rsc/shaders/simple-shader.vs
-    ./rsc/shaders/texture-shader.fs
-    ./rsc/shaders/texture-shader.vs
+    ./rsc/shaders/simple.fs
+    ./rsc/shaders/simple.vs
+    ./rsc/shaders/image.fs
+    ./rsc/shaders/image.vs
+    ./rsc/shaders/imageprocessing.fs
    ./rsc/fonts/Hack-Regular.ttf
    ./rsc/fonts/Roboto-Regular.ttf
    ./rsc/fonts/Roboto-Bold.ttf
--- a/ImGuiVisitor.cpp
+++ b/ImGuiVisitor.cpp
@@ -8,6 +8,7 @@
 #include "Scene.h"
 #include "Primitives.h"
 #include "ImageShader.h"
+#include "ImageProcessingShader.h"
 #include "MediaPlayer.h"

 #include "imgui.h"
@@ -111,7 +112,11 @@ void ImGuiVisitor::visit(Shader &n)
 {
    ImGui::PushID(n.id());

-    ImGui::ColorEdit3("color", glm::value_ptr(n.color) ) ;
+    if (ImGuiToolkit::ButtonIcon(14, 8)) {
+        n.color = glm::vec4(1.f, 1.f, 1.f, 1.f);
+    }
+    ImGui::SameLine(0, 10);
+    ImGui::ColorEdit3("Color", glm::value_ptr(n.color) ) ;

    ImGui::PopID();
 }
@@ -120,13 +125,13 @@ void ImGuiVisitor::visit(ImageShader &n)
 {
    ImGui::PushID(n.id());

-    if (ImGuiToolkit::ButtonIcon(2, 1)) {
+    if (ImGuiToolkit::ButtonIcon(4, 1)) {
        n.brightness = 0.f;
        n.contrast = 0.f;
    }
    ImGui::SameLine(0, 10);
    float bc[2] = { n.brightness, n.contrast};
-    if ( ImGui::SliderFloat2("filter", bc, -1.0, 1.0) )
+    if ( ImGui::SliderFloat2("B & C", bc, -1.0, 1.0) )
    {
        n.brightness = bc[0];
        n.contrast = bc[1];
@@ -134,6 +139,63 @@ void ImGuiVisitor::visit(ImageShader &n)
    ImGui::PopID();
 }

+void ImGuiVisitor::visit(ImageProcessingShader &n)
+{
+    ImGui::PushID(n.id());
+
+    if (ImGuiToolkit::ButtonIcon(4, 1)) {
+        n.brightness = 0.f;
+        n.contrast = 0.f;
+    }
+    ImGui::SameLine(0, 10);
+    float bc[2] = { n.brightness, n.contrast};
+    if ( ImGui::SliderFloat2("B & C", bc, -1.0, 1.0) )
+    {
+        n.brightness = bc[0];
+        n.contrast = bc[1];
+    }
+
+    if (ImGuiToolkit::ButtonIcon(2, 1)) n.saturation = 0.f;
+    ImGui::SameLine(0, 10);
+    ImGui::SliderFloat("Saturation", &n.saturation, -1.0, 1.0);
+
+    if (ImGuiToolkit::ButtonIcon(12, 4)) n.hueshift = 0.f;
+    ImGui::SameLine(0, 10);
+    ImGui::SliderFloat("Hue shift", &n.hueshift, 0.0, 1.0);
+
+    if (ImGuiToolkit::ButtonIcon(8, 1)) n.threshold = 0.f;
+    ImGui::SameLine(0, 10);
+    ImGui::SliderFloat("Threshold", &n.threshold, 0.0, 1.0);
+
+    if (ImGuiToolkit::ButtonIcon(3, 1)) n.lumakey = 0.f;
+    ImGui::SameLine(0, 10);
+    ImGui::SliderFloat("Lumakey", &n.lumakey, 0.0, 1.0);
+
+    if (ImGuiToolkit::ButtonIcon(18, 1)) n.nbColors = 0;
+    ImGui::SameLine(0, 10);
+    ImGui::SliderInt("Posterize", &n.nbColors, 0, 16);
+
+    if (ImGuiToolkit::ButtonIcon(1, 7)) n.filter = 0;
+    ImGui::SameLine(0, 10);
+    ImGui::Combo("Filter", &n.filter, "None\0Blur\0Sharpen\0Edge\0Emboss\0Erode 3x3\0Erode 5x5\0Erode 7x7\0Dilate 3x3\0Dilate 5x5\0Dilate 7x7\0");
+
+    if (ImGuiToolkit::ButtonIcon(7, 1)) n.invert = 0;
+    ImGui::SameLine(0, 10);
+    ImGui::Combo("Invert", &n.invert, "None\0Invert color\0Invert Luminance\0");
+
+    if (ImGuiToolkit::ButtonIcon(14, 4)) n.chromadelta = 0.f;
+    ImGui::SameLine(0, 10);
+    ImGui::SliderFloat("Chromakey", &n.chromadelta, 0.0, 1.0);
+
+    if (ImGuiToolkit::ButtonIcon(6, 4))
+        n.chromakey = glm::vec4(0.f, 1.f, 0.f, 1.f);
+    ImGui::SameLine(0, 10);
+    ImGui::ColorEdit3("Chroma color", glm::value_ptr(n.chromakey) ) ;
+
+
+    ImGui::PopID();
+}
+
 void ImGuiVisitor::visit(Scene &n)
 {
    ImGui::SetNextItemOpen(true, ImGuiCond_Once);
--- a/ImGuiVisitor.h
+++ b/ImGuiVisitor.h
@@ -25,9 +25,10 @@ public:
    void visit(Mesh&) {}

    // Elements with attributes
-    void visit(MediaPlayer& n);
-    void visit(Shader& n);
-    void visit(ImageShader& n);
+    void visit(MediaPlayer& n) override;
+    void visit(Shader& n) override;
+    void visit(ImageShader& n) override;
+    void visit(ImageProcessingShader& n) override;
 };

 #endif // IMGUIVISITOR_H
--- a/ImageProcessingShader.cpp
+++ b/ImageProcessingShader.cpp
@@ -1,7 +1,9 @@
+#include "defines.h"
+#include "Visitor.h"
+#include "Log.h"
 #include "ImageProcessingShader.h"

-
-ShadingProgram imageProcessingShadingProgram("shaders/processing-shader.vs", "shaders/texture-shader.fs");
+ShadingProgram imageProcessingShadingProgram("shaders/image.vs", "shaders/imageprocessing.fs");

 ImageProcessingShader::ImageProcessingShader()
 {
@@ -13,9 +15,25 @@ void ImageProcessingShader::use()
 {
    Shader::use();

+    program_->setUniform("iChannelResolution[0]", iChannelResolution[0].x, iChannelResolution[0].y, iChannelResolution[0].z);
+    program_->setUniform("iChannelResolution[1]", iChannelResolution[1].x, iChannelResolution[1].y, iChannelResolution[1].z);
+
    program_->setUniform("brightness", brightness);
    program_->setUniform("contrast", contrast);
-    program_->setUniform("stipple", stipple);
+    program_->setUniform("saturation", saturation);
+    program_->setUniform("hueshift", hueshift);
+
+    program_->setUniform("threshold", threshold);
+    program_->setUniform("lumakey", lumakey);
+    program_->setUniform("nbColors", nbColors);
+    program_->setUniform("invert", invert);
+    program_->setUniform("filter", filter);
+
+    program_->setUniform("gamma", gamma);
+    program_->setUniform("levels", levels);
+    program_->setUniform("chromakey", chromakey);
+    program_->setUniform("chromadelta", chromadelta);
+
 }


@@ -23,18 +41,28 @@ void ImageProcessingShader::reset()
 {
    Shader::reset();

+    // no texture resolution yet
+    iChannelResolution[0] = glm::vec3(1.f);
+    iChannelResolution[1] = glm::vec3(1.f);
+
+    // default values for image processing
    brightness = 0.f;
    contrast = 0.f;
-    stipple = 0.f;
+    saturation = 0.f;
+    hueshift = 0.f;
+    threshold = 0.f;
+    lumakey = 0.f;
+    nbColors = 0;
+    invert = 0;
+    filter = 0;
+    gamma = glm::vec4(1.f, 1.f, 1.f, 1.f);
+    levels = glm::vec4(0.f, 1.f, 0.f, 1.f);
+    chromakey = glm::vec4(0.f, 1.f, 0.f, 0.f);
+    chromadelta = 0.f;
+
 }

 void ImageProcessingShader::accept(Visitor& v) {
    Shader::accept(v);
    v.visit(*this);
 }
-
-
-::ImageProcessingShader()
-{
-
-}
--- a/ImageProcessingShader.h
+++ b/ImageProcessingShader.h
@@ -1,6 +1,8 @@
 #ifndef IMAGEPROCESSINGSHADER_H
 #define IMAGEPROCESSINGSHADER_H

+#include <glm/glm.hpp>
+
 #include "Shader.h"

 class ImageProcessingShader : public Shader
@@ -8,15 +10,37 @@ class ImageProcessingShader : public Shader
 public:

    ImageProcessingShader();
-    virtual ~ImageShader() {}
+    virtual ~ImageProcessingShader() {}

    virtual void use();
    virtual void reset();
    virtual void accept(Visitor& v);

-    float brightness;
-    float contrast;
-    float stipple;
+    // textures resolution
+    glm::vec3 iChannelResolution[2];
+
+    // color effects
+    float brightness; // [-1 1]
+    float contrast;   // [-1 1]
+    float saturation; // [-1 1]
+    float hueshift;   // [0 1]
+    float threshold;  // [0 1]
+    float lumakey;    // [0 1]
+    // gamma
+    glm::vec4 gamma;
+    glm::vec4 levels;
+    // discrete operations
+    int nbColors;
+    int invert;
+    // chroma key
+    glm::vec4 chromakey;
+    float chromadelta;
+    // filter
+    // [0] No filter
+    // [1 4] 4 x kernel operations;  Blur, Sharpen, Edge, Emboss
+    // [5 10] 6 x convolutions: erosion 3, 5, 7, dilation 3, 5, 7
+    int filter;
+
 };


--- a/ImageShader.cpp
+++ b/ImageShader.cpp
@@ -2,7 +2,7 @@
 #include "Visitor.h"
 #include "ImageShader.h"

-ShadingProgram imageShadingProgram("shaders/texture-shader.vs", "shaders/texture-shader.fs");
+ShadingProgram imageShadingProgram("shaders/image.vs", "shaders/image.fs");

 ImageShader::ImageShader()
 {
--- a/PickingVisitor.h
+++ b/PickingVisitor.h
@@ -31,11 +31,6 @@ public:
    void visit(LineSquare&);
    void visit(LineCircle& n);
    void visit(Mesh&){}
-
-    // not picking other Elements with attributes
-    void visit(MediaPlayer&) {}
-    void visit(Shader&) {}
-    void visit(ImageShader&) {}
 };

 #endif // PICKINGVISITOR_H
--- a/SearchVisitor.h
+++ b/SearchVisitor.h
@@ -33,10 +33,6 @@ public:
    void visit(LineCircle&) {}
    void visit(Mesh&) {}

-    // not nodes
-    void visit(MediaPlayer&) {}
-    void visit(Shader&) {}
-    void visit(ImageShader&) {}
 };

 #endif // SEARCHVISITOR_H
--- a/SessionVisitor.cpp
+++ b/SessionVisitor.cpp
@@ -5,6 +5,7 @@
 #include "Primitives.h"
 #include "Mesh.h"
 #include "ImageShader.h"
+#include "ImageProcessingShader.h"
 #include "MediaPlayer.h"
 #include "GstToolkit.h"

@@ -157,13 +158,46 @@ void SessionVisitor::visit(ImageShader &n)
    // Shader of a textured type
    xmlCurrent_->SetAttribute("type", "ImageShader");

-    XMLElement *filter = xmlDoc_->NewElement("filter");
+    XMLElement *filter = xmlDoc_->NewElement("uniforms");
    filter->SetAttribute("brightness", n.brightness);
    filter->SetAttribute("contrast", n.contrast);
+    filter->SetAttribute("stipple", n.stipple);
    xmlCurrent_->InsertEndChild(filter);

 }

+void SessionVisitor::visit(ImageProcessingShader &n)
+{
+    // Shader of a textured type
+    xmlCurrent_->SetAttribute("type", "ImageProcessingShader");
+
+    XMLElement *filter = xmlDoc_->NewElement("uniforms");
+    filter->SetAttribute("brightness", n.brightness);
+    filter->SetAttribute("contrast", n.contrast);
+    filter->SetAttribute("saturation", n.saturation);
+    filter->SetAttribute("hueshift", n.hueshift);
+    filter->SetAttribute("threshold", n.threshold);
+    filter->SetAttribute("lumakey", n.lumakey);
+    filter->SetAttribute("nbColors", n.nbColors);
+    filter->SetAttribute("invertMode", n.invert);
+    filter->SetAttribute("chromadelta", n.chromadelta);
+    filter->SetAttribute("filter", n.filter);
+    xmlCurrent_->InsertEndChild(filter);
+
+    XMLElement *gamma = XMLElementFromGLM(xmlDoc_, n.gamma);
+    gamma->SetAttribute("type", "gamma");
+    xmlCurrent_->InsertEndChild(gamma);
+
+    XMLElement *levels = XMLElementFromGLM(xmlDoc_, n.levels);
+    levels->SetAttribute("type", "levels");
+    xmlCurrent_->InsertEndChild(levels);
+
+    XMLElement *chromakey = XMLElementFromGLM(xmlDoc_, n.chromakey);
+    chromakey->SetAttribute("type", "chromakey");
+    xmlCurrent_->InsertEndChild(chromakey);
+
+}
+
 void SessionVisitor::visit(LineStrip &n)
 {
    // Node of a different type
--- a/SessionVisitor.h
+++ b/SessionVisitor.h
@@ -35,6 +35,7 @@ public:
    void visit(MediaPlayer& n);
    void visit(Shader& n);
    void visit(ImageShader& n);
+    void visit(ImageProcessingShader& n);
 };

 #endif // XMLVISITOR_H
--- a/Shader.cpp
+++ b/Shader.cpp
@@ -20,7 +20,7 @@

 // Globals
 ShadingProgram *ShadingProgram::currentProgram_ = nullptr;
-ShadingProgram simpleShadingProgram("shaders/simple-shader.vs", "shaders/simple-shader.fs");
+ShadingProgram simpleShadingProgram("shaders/simple.vs", "shaders/simple.fs");

 // Blending presets for matching with Shader::BlendMode
 GLenum blending_equation[6] = { GL_FUNC_ADD, GL_FUNC_ADD, GL_FUNC_REVERSE_SUBTRACT, GL_FUNC_ADD, GL_FUNC_REVERSE_SUBTRACT, GL_FUNC_ADD};
@@ -194,8 +194,8 @@ void Shader::use()
    program_->setUniform("modelview", modelview);
    program_->setUniform("color", color);

-    resolution = glm::vec3( Rendering::manager().currentAttrib().viewport, 0.f);
-    program_->setUniform("resolution", resolution);
+    iResolution = glm::vec3( Rendering::manager().currentAttrib().viewport, 0.f);
+    program_->setUniform("iResolution", iResolution);

    // Blending Function
    if ( blending != BLEND_NONE) {
@@ -212,7 +212,7 @@ void Shader::reset()
 {
    projection = glm::identity<glm::mat4>();
    modelview  = glm::identity<glm::mat4>();
-    resolution = glm::vec3(1280.f, 720.f, 0.f);
+    iResolution = glm::vec3(1280.f, 720.f, 0.f);
    color = glm::vec4(1.f, 1.f, 1.f, 1.f);
 }

--- a/Shader.h
+++ b/Shader.h
@@ -66,7 +66,7 @@ public:

 protected:
    ShadingProgram *program_;
-    glm::vec3 resolution;
+    glm::vec3 iResolution;

 };

--- a/Source.cpp
+++ b/Source.cpp
@@ -7,6 +7,7 @@
 #include "defines.h"
 #include "FrameBuffer.h"
 #include "ImageShader.h"
+#include "ImageProcessingShader.h"
 #include "Resource.h"
 #include "Primitives.h"
 #include "Mesh.h"
@@ -23,7 +24,6 @@ Source::Source(std::string name) : name_(""), initialized_(false)
    rename(name);

    // create groups for each view
-
    // default rendering node
    groups_[View::RENDERING] = new Group;
    groups_[View::RENDERING]->scale_ = glm::vec3(5.f, 5.f, 1.f); // fit height full window
@@ -35,12 +35,18 @@ Source::Source(std::string name) : name_(""), initialized_(false)
    groups_[View::MIXING]->addChild(frame);
    groups_[View::MIXING]->scale_ = glm::vec3(0.2f, 0.2f, 1.f);

+    // will be associated to nodes later
+    rendershader_ = new ImageProcessingShader();
+
    // add source to the list
    sources_.push_front(this);
 }

 Source::~Source()
 {
+    // delete shader
+    delete rendershader_;
+
    // delete groups and their children
    delete groups_[View::RENDERING];
    delete groups_[View::MIXING];
@@ -148,14 +154,6 @@ MediaSource::~MediaSource()
    // TODO verify that all surfaces and node is deleted in Source destructor
 }

-ImageShader *MediaSource::shader() const
-{
-    if (!rendersurface_)
-        return nullptr;
-
-    return static_cast<ImageShader *>(rendersurface_->shader());
-}
-
 std::string MediaSource::uri() const
 {
    return uri_;
@@ -182,9 +180,12 @@ void MediaSource::init()
            // create Frame buffer matching size of media player
            renderbuffer_ = new FrameBuffer(mediaplayer()->width(), mediaplayer()->height());

+            // setup shader resolution for texture 0
+            rendershader_->iChannelResolution[0] = glm::vec3(mediaplayer()->width(), mediaplayer()->height(), 0.f);
+
            // create the surfaces to draw the frame buffer in the views
            // TODO Provide the source specific effect shader
-            rendersurface_ = new FrameBufferSurface(renderbuffer_);
+            rendersurface_ = new FrameBufferSurface(renderbuffer_, rendershader_);
            groups_[View::RENDERING]->addChild(rendersurface_);
            groups_[View::MIXING]->addChild(rendersurface_);

@@ -225,7 +226,7 @@ void MediaSource::render(bool current)

        // read position of the mixing node and interpret this as transparency of render output
        float alpha = 1.0 - CLAMP( SQUARE( glm::length(groups_[View::MIXING]->translation_) ), 0.f, 1.f );
-        rendersurface_->shader()->color.a = alpha;
+        rendershader_->color.a = alpha;


        // make Mixing Overlay visible if it is current source
--- a/Source.h
+++ b/Source.h
@@ -7,7 +7,7 @@

 #include "View.h"

-class ImageShader;
+class ImageProcessingShader;
 class Surface;
 class FrameBuffer;
 class MediaPlayer;
@@ -35,7 +35,7 @@ public:
    inline Group *group(View::Mode m) const { return groups_.at(m); }

    // every Source have a shader to control visual effects
-    virtual ImageShader *shader() const = 0;
+    inline ImageProcessingShader *shader() const { return rendershader_; }

    // every Source shall be rendered before draw
    virtual void render(bool current) = 0;
@@ -64,10 +64,14 @@ protected:
    FrameBuffer *renderbuffer_;

    // the rendersurface draws the renderbuffer in the scene
-    // It is associated to the sourceshader for mixing effects
+    // It is associated to the rendershader for mixing effects
    // (aka visual effect applied in scene, not in render() )
    FrameBufferSurface *rendersurface_;

+    // rendershader provides all image processing controls for
+    // mixing sources in the scene
+    ImageProcessingShader *rendershader_;
+
    // static global list of sources
    static SourceList sources_;
 };
@@ -101,9 +105,6 @@ public:

    void render(bool current);

-    // Source interface
-    ImageShader *shader() const;
-
    // Media specific interface
    std::string uri() const;
    MediaPlayer *mediaplayer() const;
--- a/Visitor.h
+++ b/Visitor.h
@@ -21,6 +21,7 @@ class Mesh;
 class MediaPlayer;
 class Shader;
 class ImageShader;
+class ImageProcessingShader;

 // Declares the interface for the visitors
 class Visitor {
@@ -42,9 +43,11 @@ public:
    virtual void visit (LineCircle&) = 0;
    virtual void visit (Mesh&) = 0;

-    virtual void visit (MediaPlayer&) = 0;
-    virtual void visit (Shader&) = 0;
-    virtual void visit (ImageShader&) = 0;
+    // not mandatory
+    virtual void visit (MediaPlayer&) {}
+    virtual void visit (Shader&) {}
+    virtual void visit (ImageShader&) {}
+    virtual void visit (ImageProcessingShader&) {}

 };

--- a/main.cpp
+++ b/main.cpp
@@ -33,6 +33,7 @@
 #include "RenderingManager.h"
 #include "UserInterfaceManager.h"
 #include "FrameBuffer.h"
+#include "ImageProcessingShader.h"

 #include "MediaPlayer.h"
 #include "Scene.h"
@@ -189,8 +190,14 @@ void drawScene()
    // draw GUI tree scene
    ImGui::Begin(IMGUI_TITLE_MAINWINDOW);
    static ImGuiVisitor v;
-    Mixer::manager().currentView()->scene.accept(v);
+//    Mixer::manager().currentView()->scene.accept(v);
 //    Mixer::manager().getView(View::RENDERING)->scene.accept(v);
+
+    Source *s = Mixer::manager().currentSource();
+    if ( s != nullptr) {
+        s->shader()->accept(v);
+    }
+
    ImGui::End();
 }

--- a/rsc/images/shadow.png
+++ b/rsc/images/shadow.png
--- a/rsc/images/shadow_dark.png
+++ b/rsc/images/shadow_dark.png
--- a/rsc/mesh/circle.ply
+++ b/rsc/mesh/circle.ply
@@ -0,0 +1,462 @@
+ply
+format ascii 1.0
+comment Created by Blender 2.82 (sub 7) - www.blender.org, source file: 'circle.blend'
+element vertex 192
+property float x
+property float y
+property float z
+property uchar red
+property uchar green
+property uchar blue
+property uchar alpha
+element face 256
+property list uchar uint vertex_indices
+end_header
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--- a/rsc/shaders/texture-shader.fs
+++ b/rsc/shaders/texture-shader.fs
@@ -5,17 +5,18 @@ out vec4 FragColor;
 in vec4 vertexColor;
 in vec2 vertexUV;

-uniform sampler2D sourceTexture;
+uniform sampler2D iChannel0;             // input channel (texture id).
+uniform vec3      iResolution;           // viewport resolution (in pixels)
+
 uniform vec4 color;
 uniform float contrast;
 uniform float brightness;
 uniform float stipple;
-uniform vec3  resolution;           // viewport resolution (in pixels)

 void main()
 {
    // color is a mix of texture (manipulated with brightness & contrast), vertex and uniform colors
-    vec4 textureColor = texture(sourceTexture, vertexUV);
+    vec4 textureColor = texture(iChannel0, vertexUV);
    vec3 RGB = mix(vec3(0.62), textureColor.rgb, contrast + 1.0) + brightness;
    RGB *= vertexColor.rgb * color.rgb;

--- a/rsc/shaders/texture-shader.vs
+++ b/rsc/shaders/texture-shader.vs
--- a/rsc/shaders/imageprocessing.fs
+++ b/rsc/shaders/imageprocessing.fs
@@ -0,0 +1,326 @@
+#version 330 core
+
+/*
+** Gamma correction
+** Details: http://blog.mouaif.org/2009/01/22/photoshop-gamma-correction-shader/
+*/
+#define GammaCorrection(color, gamma) pow( color, 1.0 / vec3(gamma))
+
+/*
+** Levels control (input (+gamma), output)
+** Details: http://blog.mouaif.org/2009/01/28/levels-control-shader/
+*/
+#define LevelsControlInputRange(color, minInput, maxInput)  min(max(color - vec3(minInput), 0.0) / (vec3(maxInput) - vec3(minInput)), 1.0)
+#define LevelsControlInput(color, minInput, gamma, maxInput) GammaCorrection(LevelsControlInputRange(color, minInput, maxInput), gamma)
+#define LevelsControlOutputRange(color, minOutput, maxOutput)  mix(vec3(minOutput), vec3(maxOutput), color)
+#define LevelsControl(color, minInput, gamma, maxInput, minOutput, maxOutput)   LevelsControlOutputRange(LevelsControlInput(color, minInput, gamma, maxInput), minOutput, maxOutput)
+
+#define ONETHIRD 0.333333
+#define TWOTHIRD 0.666666
+#define EPSILON  0.000001
+
+out vec4 FragColor;
+
+// from vertex shader (interpolated)
+in vec4 vertexColor;
+in vec2 vertexUV;
+
+// general shader uniforms
+uniform vec4 color;
+
+// image processing specific
+uniform sampler2D iChannel0;  // input channel (texture id).
+uniform sampler2D iChannel1;
+uniform vec3      iChannelResolution[2]; // input channel resolution (in pixels)
+uniform vec3      iResolution;           // viewport resolution (in pixels)
+
+uniform float contrast;
+uniform float brightness;
+uniform float saturation;
+uniform vec4  gamma;
+uniform vec4  levels;
+uniform float hueshift;
+uniform vec4  chromakey;
+uniform float chromadelta;
+uniform float threshold;
+uniform float lumakey;
+uniform int   nbColors;
+uniform int   invert;
+uniform int   filter;
+
+// conversion between rgb and YUV
+const mat4 RGBtoYUV = mat4(0.257,  0.439, -0.148, 0.0,
+                           0.504, -0.368, -0.291, 0.0,
+                           0.098, -0.071,  0.439, 0.0,
+                           0.0625, 0.500,  0.500, 1.0 );
+
+const mat3 KERNEL[5] = mat3[5]( mat3( 0.0, 0.0, 0.0,
+                                      0.0, 1.0, 0.0,
+                                      0.0, 0.0, 0.0),
+                                mat3( 0.0625, 0.125, 0.0625,
+                                      0.125, 0.25, 0.125,
+                                      0.0625, 0.125, 0.0625),
+                                mat3( -1.0, -1.0, -1.0,
+                                      -1.0, 9.0, -1.0,
+                                      -1.0, -1.0, -1.0),
+                                mat3( -2.0, 1.0, -2.0,
+                                      1.0, 4.0, 1.0,
+                                      -2.0, 1.0, -2.0),
+                                mat3( -2.0, -1.0, 0.0,
+                                      -1.0, 1.0, 1.0,
+                                      0.0, 1.0, 2.0)
+                                );
+
+vec3 erosion(int N, vec2 filter_step)
+{
+    vec3 minValue = vec3(1.0);
+
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0,0.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0,-1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0, 0.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (1.0, 0.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0, 1.0) * filter_step ).rgb, minValue);
+    if (N == 3)
+        return minValue;
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0, -2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0,-2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (1.0,-2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0,2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0, 2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (1.0, 2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-2.0, 1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0, 1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 1.0, 1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 2.0, 1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-2.0, -1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0, -1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 1.0, -1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 2.0, -1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-2.0, 0.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 2.0, 0.0) * filter_step ).rgb, minValue);
+    if (N == 5)
+        return minValue;
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0, -3.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0,-3.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (1.0,-3.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-1.0,3.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (0.0, 3.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (1.0, 3.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-2.0, 2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 2.0, 2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-2.0, -2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 2.0, -2.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-3.0, -1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (3.0, -1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-3.0, 1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 3.0, 1.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 (-3.0, 0.0) * filter_step ).rgb, minValue);
+    minValue = min(texture2D(iChannel0, vertexUV + vec2 ( 3.0, 0.0) * filter_step ).rgb, minValue);
+
+    return minValue;
+}
+
+vec3 dilation(int N, vec2 filter_step)
+{
+    vec3 maxValue = vec3(0.0);
+
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0, 0.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0,-1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0, 0.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (1.0, 0.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0, 1.0) * filter_step ).rgb, maxValue);
+    if (N == 3)
+        return maxValue;
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0, -2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0,-2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (1.0,-2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0,2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0, 2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (1.0, 2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-2.0, 1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0, 1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 1.0, 1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 2.0, 1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-2.0, -1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0, -1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 1.0, -1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 2.0, -1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-2.0, 0.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 2.0, 0.0) * filter_step ).rgb, maxValue);
+    if (N == 5)
+        return maxValue;
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0, -3.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0,-3.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (1.0,-3.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-1.0,3.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (0.0, 3.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (1.0, 3.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-2.0, 2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 2.0, 2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-2.0, -2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 2.0, -2.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-3.0, -1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (3.0, -1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-3.0, 1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 3.0, 1.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 (-3.0, 0.0) * filter_step ).rgb, maxValue);
+    maxValue = max(texture2D(iChannel0, vertexUV + vec2 ( 3.0, 0.0) * filter_step ).rgb, maxValue);
+
+    return maxValue;
+}
+
+vec3 convolution(mat3 kernel, vec2 filter_step)
+{
+    int i = 0, j = 0;
+    vec3 sum = vec3(0.0);
+
+    for (i = 0; i<3; ++i)
+        for (j = 0; j<3; ++j)
+            sum += texture(iChannel0, vertexUV + filter_step * vec2 (i-1, j-1) ).rgb * kernel[i][j];
+
+    return sum;
+}
+
+vec3 apply_filter() {
+
+    vec2 filter_step = vec2( 1.f / iChannelResolution[0].x, 1.f / iChannelResolution[0].y);
+//    vec2 filter_step = vec2( 1.f / 1280.0, 1.f / 720.0);
+
+    if (filter < 1 || filter > 10)
+        return texture(iChannel0, vertexUV).rgb;
+    else if (filter < 5)
+        return convolution( KERNEL[filter], filter_step);
+    else if (filter < 8)
+        return erosion( 3 + (filter -5) * 2, filter_step);
+    else
+        return dilation( 3 + (filter -8) * 2, filter_step);
+}
+
+/*
+** Hue, saturation, luminance <=> Red Green Blue
+*/
+
+float HueToRGB(float f1, float f2, float hue)
+{
+    float res;
+
+    hue += mix( -float( hue > 1.0 ), 1.0, float(hue < 0.0) );
+
+    res = mix( f1, mix( clamp( f1 + (f2 - f1) * ((2.0 / 3.0) - hue) * 6.0, 0.0, 1.0) , mix( f2,  clamp(f1 + (f2 - f1) * 6.0 * hue, 0.0, 1.0), float((6.0 * hue) < 1.0)),  float((2.0 * hue) < 1.0)), float((3.0 * hue) < 2.0) );
+
+    return res;
+}
+
+vec3 HSV2RGB(vec3 hsl)
+{
+    vec3 rgb;
+    float f1, f2;
+
+    f2 = mix( (hsl.z + hsl.y) - (hsl.y * hsl.z), hsl.z * (1.0 + hsl.y), float(hsl.z < 0.5) );
+
+    f1 = 2.0 * hsl.z - f2;
+
+    rgb.r = HueToRGB(f1, f2, hsl.x + ONETHIRD);
+    rgb.g = HueToRGB(f1, f2, hsl.x);
+    rgb.b = HueToRGB(f1, f2, hsl.x - ONETHIRD);
+
+    rgb =  mix( rgb, vec3(hsl.z), float(hsl.y < EPSILON));
+
+    return rgb;
+}
+
+vec3 RGB2HSV( vec3 color )
+{
+    vec3 hsl = vec3(0.0); // init to 0
+
+    float fmin = min(min(color.r, color.g), color.b);    //Min. value of RGB
+    float fmax = max(max(color.r, color.g), color.b);    //Max. value of RGB
+    float delta = fmax - fmin + EPSILON;             //Delta RGB value
+
+    vec3 deltaRGB = ( ( vec3(fmax) - color ) / 6.0  + vec3(delta) / 2.0 ) / delta ;
+
+    hsl.z = (fmax + fmin) / 2.0; // Luminance
+
+    hsl.y = delta / ( EPSILON + mix( 2.0 - fmax - fmin, fmax + fmin, float(hsl.z < 0.5)) );
+
+    hsl.x = mix( hsl.x, TWOTHIRD + deltaRGB.g - deltaRGB.r, float(color.b == fmax));
+    hsl.x = mix( hsl.x, ONETHIRD + deltaRGB.r - deltaRGB.b, float(color.g == fmax));
+    hsl.x = mix( hsl.x, deltaRGB.b - deltaRGB.g,  float(color.r == fmax));
+
+    hsl.x += mix( - float( hsl.x > 1.0 ), 1.0, float(hsl.x < 0.0) );
+
+    hsl = mix ( hsl, vec3(-1.0, 0.0, hsl.z), float(delta<EPSILON) );
+
+    return hsl;
+}
+
+float alphachromakey(vec3 color, vec3 colorKey, float delta)
+{
+   // magic values
+   vec2 tol = vec2(0.5, 0.4*delta);
+
+   //convert from RGB to YCvCr/YUV
+   vec4 keyYuv = RGBtoYUV * vec4(colorKey, 1.0);
+   vec4 yuv = RGBtoYUV * vec4(color, 1.0);
+
+   // color distance in the UV (CbCr, PbPr) plane
+   vec2 dif = yuv.yz - keyYuv.yz;
+   float d = sqrt(dot(dif, dif));
+
+   // tolerance clamping
+   return max( (1.0 - step(d, tol.y)), step(tol.x, d) * (d - tol.x) / (tol.y - tol.x));
+}
+
+
+void main(void)
+{
+
+    // deal with alpha separately
+    float ma = texture(iChannel0, vertexUV).a;
+//    float ma = texture(maskTexture, vertexUV).a * texture(iChannel0, vertexUV).a;
+    float alpha = clamp(ma * color.a, 0.0, 1.0);
+
+    // read color & apply basic filter
+    vec3 transformedRGB;
+    transformedRGB = apply_filter();
+
+    // chromakey
+    alpha -= mix( 0.0, 1.0 - alphachromakey( transformedRGB, chromakey.rgb, chromadelta), float(chromadelta > 0.0001) );
+
+    // color transformation
+    transformedRGB = mix(vec3(0.62), transformedRGB, contrast + 1.0) + brightness;
+    transformedRGB = LevelsControl(transformedRGB, levels.x, gamma.rgb * gamma.a, levels.y, levels.z, levels.w);
+
+    // RGB invert
+    transformedRGB = vec3(float(invert==1)) + ( transformedRGB * vec3(1.0 - 2.0 * float(invert==1)) );
+
+    // Convert to HSL
+    vec3 transformedHSL = RGB2HSV( transformedRGB );
+
+    // Luminance invert
+    transformedHSL.z = float(invert==2) +  transformedHSL.z * (1.0 - 2.0 * float(invert==2) );
+
+    // perform hue shift
+    transformedHSL.x = transformedHSL.x + hueshift;
+
+    // Saturation
+    transformedHSL.y *= saturation + 1.0;
+
+    // perform reduction of colors
+    transformedHSL = mix( transformedHSL, floor(transformedHSL * vec3(nbColors)) / vec3(nbColors-1),  float( nbColors > 0 ) );
+
+    // luma key
+    alpha -= mix( 0.0, step( transformedHSL.z, lumakey ), float(lumakey > EPSILON));
+
+    // level threshold
+    transformedHSL = mix( transformedHSL, vec3(0.0, 0.0, step( transformedHSL.z, threshold )), float(threshold > EPSILON));
+
+    // after operations on HSL, convert back to RGB
+    transformedRGB = HSV2RGB(transformedHSL);
+
+    // apply base color and alpha for final fragment color
+    FragColor = vec4(transformedRGB * vertexColor.rgb * color.rgb, clamp(alpha, 0.0, 1.0) );
+
+}
+
+
--- a/rsc/shaders/simple-shader.fs
+++ b/rsc/shaders/simple-shader.fs
@@ -5,7 +5,7 @@ out vec4 FragColor;
 in vec4 vertexColor;

 uniform vec4 color;            // drawing color
-uniform vec3 resolution;      // viewport resolution (in pixels)
+uniform vec3 iResolution;      // viewport resolution (in pixels)

 void main()
 {
--- a/rsc/shaders/simple-shader.vs
+++ b/rsc/shaders/simple-shader.vs