fixed translating, added zooming

Vertex.glsl

@@ -8,7 +8,6 @@ out vec2 complexPos;
 
 void main(){
     vec2 offset = (pos + 1) / 2 * size;
-    offset.y *= -1;
     complexPos = origin + offset;
-    gl_Position = vec4(pos.xy, 0.0, 1.);
+    gl_Position = vec4(pos.xy, 0, 1);
 }

headers/Mandelbrot.h

@@ -11,10 +11,10 @@ public:
 	void draw(GLuint, QOpenGLShaderProgram&);
 	void setIterations(int);
 	void translateRelative(QVector2D);
-	void zoomRelative(double, QVector2D);
+	void zoomRelative(float, QVector2D);
 private:
 	int iterations = 0;
-	QVector2D origin {-2, 1};
+	QVector2D origin {-2, -1};
 	QVector2D size {2, 2};
 	void setShaderValues(QOpenGLShaderProgram&) const;
 };

src/Mandelbrot.cpp

@@ -19,8 +19,12 @@ void Mandelbrot::setShaderValues(QOpenGLShaderProgram &shader) const {
 	shader.setUniformValue("iterationCount", iterations);
 }
 
-void Mandelbrot::zoomRelative(double delta, QVector2D posRelative) {
-
+void Mandelbrot::zoomRelative(float delta, QVector2D posRelative) {
+	QVector2D newSize = size * delta;
+	QVector2D fixPos = origin + posRelative * size;
+	QVector2D newOrigin = fixPos - posRelative * newSize;
+	size = newSize;
+	origin = newOrigin;
 }
 
 void Mandelbrot::setIterations(int value) {

src/OutputWidget.cpp

@@ -72,12 +72,15 @@ QVector2D relative(QPoint p, QSize s){
 }
 
 void OutputWidget::wheelEvent(QWheelEvent *e) {
-	double modifier = 1;
+	QPoint pos = e->position().toPoint();
+	float modifier = 1;
 	if (e->angleDelta().y() > 0)
-		modifier *= 1.1;
-	else
 		modifier /= 1.1;
-	getMandelbrot()->zoomRelative(modifier, relative(mousePos, size()));
+	else
+		modifier *= 1.1;
+	QVector2D relativePos = relative(pos, size());
+	relativePos.setY(1 - relativePos.y());
+	getMandelbrot()->zoomRelative(modifier, relativePos);
 	update();
 }
 
@@ -85,7 +88,9 @@ void OutputWidget::mouseMoveEvent(QMouseEvent *e) {
 	QPoint newMousePos = e->pos();
 	QPoint diff = newMousePos - mousePos;
 	mousePos = newMousePos;
-	getMandelbrot()->translateRelative(relative(diff, size()));
+	QVector2D relativeDiff = relative(diff, size());
+	relativeDiff.setY(-relativeDiff.y());
+	getMandelbrot()->translateRelative(relativeDiff);
 	update();
 }