New ImageFilter applied to Clone Sources

Preliminary implementation, effective but without consequence on the rendering.

ImageFilter.h

@@ -0,0 +1,69 @@
+#ifndef IMAGEFILTER_H
+#define IMAGEFILTER_H
+
+#include <map>
+
+class Surface;
+class FrameBuffer;
+
+#include "Shader.h"
+
+class ImageFilteringShader : public Shader
+{
+    ShadingProgram custom_shading_;
+
+    // fragment shader GLSL code
+    std::string code_;
+
+    // list of uniform vars in GLSL
+    // with associated pair (current_value, default_values) in range [0.f 1.f]
+    std::map<std::string, glm::vec2> uniforms_;
+
+public:
+
+    ImageFilteringShader();
+    ~ImageFilteringShader();
+
+    void use() override;
+    void reset() override;
+    void accept(Visitor& v) override;
+    void copy(ImageFilteringShader const& S);
+
+    // set fragment shader code and uniforms (with default values)
+    void setFragmentCode(const std::string &code, std::map<std::string, float> parameters);
+};
+
+
+class ImageFilter
+{
+    Surface *surface_;
+    FrameBuffer *buffer_;
+    ImageFilteringShader *shader_;
+    uint type_;
+
+public:
+
+    // instanciate an image filter at given resolution, with alpha channel
+    ImageFilter(glm::vec3 resolution, bool useAlpha = false);
+    ~ImageFilter();
+
+    // set the texture to draw into the framebuffer
+    void setInputTexture(uint t);
+
+//    typedef enum {
+
+//    } ;
+
+
+    void setFilter(uint filter);
+
+    // draw the input texture with filter on the framebuffer
+    void draw();
+
+    // get the texture id of the rendered framebuffer
+    uint getOutputTexture() const;
+
+};
+
+
+#endif // IMAGEFILTER_H