Implementation of stippling in GLSL image shader and use in Mixing

Source. Creation of Mxing circle texture.

ImageShader.cpp

@@ -16,6 +16,7 @@ void ImageShader::use()
 
     program_->setUniform("brightness", brightness);
     program_->setUniform("contrast", contrast);
+    program_->setUniform("stipple", stipple);
 }
 
 
@@ -25,6 +26,7 @@ void ImageShader::reset()
 
     brightness = 0.f;
     contrast = 0.f;
+    stipple = 0.f;
 }
 
 void ImageShader::accept(Visitor& v) {

ImageShader.h

@@ -16,6 +16,7 @@ public:
 
     float brightness;
     float contrast;
+    float stipple;
 };
 
 #endif // IMAGESHADER_H

Mesh.cpp

@@ -332,20 +332,31 @@ Mesh::Mesh(const std::string& ply_path, const std::string& tex_path) : Primitive
         Log::Warning("Mesh could not be created from %s", ply_path.c_str());
     }
 
-    // selective creation of the shader (deleted in Primitive)
-    if (texture_resource_.empty())
+    // default non texture shader (deleted in Primitive)
     shader_ = new Shader;
-    else
-        shader_ = new ImageShader;
 }
 
 
+void Mesh::setTexture(uint textureindex)
+{
+    if (textureindex) {
+
+        // replace previous shader with a new Image Shader
+        if (shader_)
+            delete shader_;
+        shader_ = new ImageShader;
+
+        textureindex_ = textureindex;
+    }
+
+}
+
 void Mesh::init()
 {
     Primitive::init();
 
     if (!texture_resource_.empty())
-        textureindex_ = Resource::getTextureImage(texture_resource_);
+        setTexture(Resource::getTextureImage(texture_resource_));
 
 }
 

Mesh.h

@@ -18,6 +18,8 @@ class Mesh : public Primitive {
 public:
     Mesh(const std::string& ply_path, const std::string& tex_path = "");
 
+    void setTexture(uint textureindex);
+
     void init () override;
     void draw (glm::mat4 modelview, glm::mat4 projection) override;
     void accept (Visitor& v) override;

Primitives.cpp

@@ -125,6 +125,8 @@ void MediaSurface::init()
 
     mediaplayer_->open(uri_);
     mediaplayer_->play(true);
+
+
 }
 
 void MediaSurface::draw(glm::mat4 modelview, glm::mat4 projection)

RenderingManager.cpp

@@ -49,7 +49,6 @@
 // local statics
 static GstGLContext *global_gl_context = NULL;
 static GstGLDisplay *global_display = NULL;
-//static guintptr global_window_handle = 0;
 
 static void glfw_error_callback(int error, const char* description)
 {
@@ -167,8 +166,6 @@ bool Rendering::Init()
                                         (guintptr) glfwGetGLXContext(main_window_),
                                         GST_GL_PLATFORM_GLX, GST_GL_API_OPENGL);
 
-    global_window_handle =  (guintptr) glfwGetX11Window(main_window_);
-
 #endif
 
     // TODO : force GPU decoding

Source.cpp

@@ -3,6 +3,7 @@
 
 #include "Source.h"
 
+#include "defines.h"
 #include "FrameBuffer.h"
 #include "ImageShader.h"
 #include "Primitives.h"
@@ -14,7 +15,7 @@
 // gobal static list of all sources
 SourceList Source::sources_;
 
-Source::Source(std::string name) : name_("")
+Source::Source(std::string name) : name_(""), initialized_(false)
 {
     // set a name
     rename(name);
@@ -30,7 +31,7 @@ Source::Source(std::string name) : name_("")
     Frame *frame = new Frame;
     frame->translation_.z = 0.1;
     groups_[View::MIXING]->addChild(frame);
-    groups_[View::MIXING]->scale_ = glm::vec3(0.25f, 0.25f, 1.f);
+    groups_[View::MIXING]->scale_ = glm::vec3(0.2f, 0.2f, 1.f);
 
     // add source to the list
     sources_.push_front(this);
@@ -147,8 +148,19 @@ MediaPlayer *MediaSource::mediaplayer() const
     return surface_->getMediaPlayer();
 }
 
+void MediaSource::init()
+{
+    ImageShader *is = static_cast<ImageShader *>(surface_->shader());
+    if (is)
+        is->stipple = 1.0;
+
+    initialized_ = true;
+}
+
 void MediaSource::render()
 {
+    if (!initialized_)
+        init();
 //    surface_->shader()
 
     // scalle all mixing nodes to match scale of surface
@@ -158,7 +170,9 @@ void MediaSource::render()
     }
 
     // read position of the mixing node and interpret this as transparency change
-    float alpha = 1.0 - ABS( groups_[View::MIXING]->translation_.x );
+    float alpha = 1.0 - SQUARE( glm::length(groups_[View::MIXING]->translation_) );
     surface_->shader()->color.a = alpha;
 
+
+
 }

Source.h

@@ -51,6 +51,10 @@ protected:
     // name
     std::string name_;
 
+    // every Source shall be initialized on first draw
+    bool initialized_;
+    virtual void init() = 0;
+
     // nodes
     std::map<View::Mode, Group*> groups_;
 
@@ -96,6 +100,8 @@ public:
 
 protected:
 
+    virtual void init();
+
     MediaSurface *surface_;
 };
 

View.cpp

@@ -3,14 +3,20 @@
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 
+// memmove
+#include <string.h>
+
 #include "defines.h"
 #include "View.h"
 #include "Source.h"
 #include "Primitives.h"
+#include "Resource.h"
 #include "Mesh.h"
 #include "FrameBuffer.h"
 #include "Log.h"
 
+#define CIRCLE_PIXELS 64
+#define CIRCLE_PIXEL_RADIUS 1024.0
 
 View::View()
 {
@@ -24,8 +30,12 @@ void View::update(float dt)
 
 MixingView::MixingView() : View()
 {
+    // default settings
+    scene.root()->scale_ = glm::vec3(1.4, 1.4, 1.0);
+
     // Mixing scene
-    Mesh *disk = new Mesh("mesh/disk.ply", "images/transparencygrid.png");
+    Mesh *disk = new Mesh("mesh/disk.ply");
+    disk->setTexture(textureMixingQuadratic());
     backgound_.addChild(disk);
 
     glm::vec4 pink( 0.8f, 0.f, 0.8f, 1.f );
@@ -104,6 +114,55 @@ void MixingView::grab (glm::vec2 from, glm::vec2 to, Source *s)
 
 }
 
+
+uint MixingView::textureMixingQuadratic()
+{
+    static GLuint texid = 0;
+    if (texid == 0) {
+        // generate the texture with alpha exactly as computed for sources
+        glGenTextures(1, &texid);
+        glBindTexture(GL_TEXTURE_2D, texid);
+        GLubyte matrix[CIRCLE_PIXELS*CIRCLE_PIXELS * 4];
+        GLubyte color[4] = {0,0,0,0};
+        GLfloat luminance = 1.f;
+        GLfloat alpha = 0.f;
+        GLfloat distance = 0.f;
+        int l = -CIRCLE_PIXELS / 2 + 1, c = 0;
+
+        for (int i = 0; i < CIRCLE_PIXELS / 2; ++i) {
+            c = -CIRCLE_PIXELS / 2 + 1;
+            for (int j=0; j < CIRCLE_PIXELS / 2; ++j) {
+                // distance to the center
+                distance = (GLfloat) ((c * c) + (l * l)) / CIRCLE_PIXEL_RADIUS;
+                // luminance
+                luminance = 255.f * CLAMP( 0.95f - 0.8f * distance, 0.f, 1.f);
+                color[0] = color[1] = color[2] = static_cast<GLubyte>(luminance);
+                // alpha
+                alpha = 255.f * CLAMP( 1.f - distance , 0.f, 1.f);
+                color[3] = static_cast<GLubyte>(alpha);
+
+                // 1st quadrant
+                memmove(&matrix[ j * 4 + i * CIRCLE_PIXELS * 4 ], color, 4);
+                // 4nd quadrant
+                memmove(&matrix[ (CIRCLE_PIXELS -j -1)* 4 + i * CIRCLE_PIXELS * 4 ], color, 4);
+                // 3rd quadrant
+                memmove(&matrix[ j * 4 + (CIRCLE_PIXELS -i -1) * CIRCLE_PIXELS * 4 ], color, 4);
+                // 4th quadrant
+                memmove(&matrix[ (CIRCLE_PIXELS -j -1) * 4 + (CIRCLE_PIXELS -i -1) * CIRCLE_PIXELS * 4 ], color, 4);
+
+                ++c;
+            }
+            ++l;
+        }
+        // two components texture : luminance and alpha
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, CIRCLE_PIXELS, CIRCLE_PIXELS, 0, GL_RGBA, GL_UNSIGNED_BYTE, (float *) matrix);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+    }
+    return texid;
+}
+
 RenderView::RenderView() : View(), frame_buffer_(nullptr)
 {
     setResolution(1280, 720);

View.h

@@ -38,6 +38,8 @@ public:
     void drag (glm::vec2 from, glm::vec2 to) override;
     void grab (glm::vec2 from, glm::vec2 to, Source *s) override;
 
+private:
+    uint textureMixingQuadratic();
 };
 
 class RenderView : public View
@@ -53,5 +55,6 @@ public:
     void setResolution (uint width, uint height);
     inline FrameBuffer *frameBuffer () const { return frame_buffer_; }
 
+
 };
 #endif // VIEW_H

defines.h

@@ -10,6 +10,7 @@
 #define ABS(a)	   (((a) < 0) ? -(a) : (a))
 #define ABS_DIFF(a, b) ( (a) < (b) ? (b - a) : (a - b) )
 #define SIGN(a)	   (((a) < 0) ? -1.0 : 1.0)
+#define SQUARE(a)	   ((a) * (a))
 #define CLAMP(x, low, high)  (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
 #define EPSILON 0.00001
 #define LOG100(val) (50.0/log(10.0)*log((float)val + 1.0))

rsc/shaders/texture-shader.fs

@@ -9,13 +9,16 @@ uniform sampler2D sourceTexture;
 uniform vec4 color;
 uniform float contrast;
 uniform float brightness;
+uniform float stipple;
 uniform vec3  resolution;           // viewport resolution (in pixels)
 
 void main()
 {		
-    vec4 texturecolor = texture(sourceTexture, vertexUV);
-    vec3 transformedRGB = mix(vec3(0.62), texturecolor.rgb, contrast + 1.0) + brightness;
-    transformedRGB *= vertexColor.rgb;
+    vec4 textureColor = texture(sourceTexture, vertexUV);
+    vec3 transformedRGB = mix(vec3(0.62), textureColor.rgb, contrast + 1.0) + brightness;
+    transformedRGB *= vertexColor.rgb * color.rgb;
 
-    FragColor = color * vec4(transformedRGB, texturecolor.a * vertexColor.a);
+    float a = int(gl_FragCoord.x + gl_FragCoord.y)%2 > 1 - int(stipple) ? 1.0 : color.a;
+
+    FragColor = vec4(transformedRGB, textureColor.a * vertexColor.a * a);
 }