Add small example

include/opengl-playground/openglgraphics.hpp

@@ -0,0 +1,19 @@
+#ifndef OPENGLGRAPHICS_H
+#define OPENGLGRAPHICS_H
+
+#include <string>
+#include <epoxy/gl.h>
+#include <opengl-playground/openglshader.hpp>
+
+class OpenGlGraphics
+{
+	public:
+		OpenGlGraphics(OpenGlShaderProgram &prog);
+		~OpenGlGraphics();
+		virtual void realize() = 0;
+		virtual void render() = 0;
+	protected:
+		OpenGlShaderProgram shaderprog;
+};
+
+#endif // OPENGLGRAPHICS_H

include/opengl-playground/openglshader.hpp

@@ -12,6 +12,9 @@ class OpenGlShaderProgram
 		int compile();
 		void unload();
 		int use();
+		int getUniformLoc(const std::string &uniform);
+		void setUniformFloat(const std::string &uniform, float value);
+		void setUniformVec2(const std::string &uniform, float *vector);
 	private:
 		bool compiled;
 		GLuint shader_program;

include/opengl-playground/textured-rectangle.hpp

@@ -0,0 +1,27 @@
+#ifndef TEXTURED_RECTANGLE_H
+#define TEXTURED_RECTANGLE_H
+
+#include <opengl-playground/openglgraphics.hpp>
+#include <epoxy/gl.h>
+
+class TexturedRectangle : OpenGlGraphics
+{
+	public:
+		TexturedRectangle(float x0, float y0, float x1, float y1, OpenGlShaderProgram &shaderprog);
+		void realize();
+		void render();
+		void setZoom(float zoom);
+		float getZoom();
+		void setOffset(float x_off, float y_off);
+		float getOffsetX();
+		float getOffsetY();
+	private:
+		float pos1[2];
+		float pos2[2];
+		float x_offset;
+		float y_offset;
+		float zoom;
+		GLuint vao;
+};
+
+#endif // TEXTURED_RECTANGLE_H