The 2d-viewer from nikolausrauch

Memory Corruption on MacOS

In your demo, there's a code passage at

Lines 71 to 77 in 9bb5068

    
           viewer.drawCircles(circles.begin(), circles.end(), [](auto& c, auto& pos, auto& radius, auto& color) 
        
           { 
        
               pos = c.first; 
        
               radius = c.second; 
        
               color = {0.0, 1.0, 0.0, 1.0}; 
        
               return true; 
        
           });

When executed on a MacBook (with an M1 processor), it leads to the following error:

demo(55959,0x1dc8fd000) malloc: Incorrect checksum for freed object 0x14a608310: probably modified after being freed.
Corrupt value: 0x343bbd2e3f800000
demo(55959,0x1dc8fd000) malloc: *** set a breakpoint in malloc_error_break to debug
[1]    55959 abort      ./bin/demo

It appears that the initialization of the new vector (vertices) in this function is broken on MacOS. Specifically, referring to

2D-viewer/viewer/viewer.inl

Lines 50 to 58 in 9bb5068

    
           std::vector<glm::vec2> vertices(mRender.circleVertices); 
        
           for(unsigned int i = 0; i <= mRender.circleVertices; i++) 
        
           { 
        
               vertices[i] = 
        
               { 
        
                   radius * glm::cos(2.0*glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices), 
        
                   radius * glm::sin(2.0*glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices) 
        
               }; 
        
           }

There could be two (or more) ways (for now) to fix this:

You could do something like:

#ifndef __APPLE__
std::vector<glm::vec2> vertices(mRender.circleVertices);
for (unsigned int i = 0; i <= mRender.circleVertices; i++) {
    vertices[i] = {
        radius * glm::cos(2.0 * glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices),
        radius * glm::sin(2.0 * glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices)};
}
#endif

...

for (unsigned int i = 0; i <= mRender.circleVertices; i++) {
#ifdef __APPLE__
    glVertex2f(position.x + radius * radius * glm::cos(2.0 * glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices),
                       position.y + radius * radius * glm::sin(2.0 * glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices));
#else
    glVertex2f(position.x + radius * vertices[i].x,
                       position.y + radius * vertices[i].y);
#endif
}

Or, without the #ifdef:

...
for (unsigned int i = 0; i <= mRender.circleVertices; i++) {
    const float angle = 2.0 * glm::pi<float>() * static_cast<float>(i) / mRender.circleVertices;  // For readability purposes
    glVertex2f(position.x + radius * radius * glm::cos(angle),
                       position.y + radius * radius * glm::sin(angle));
}

As you mentioned, you're not exactly sure why this happens, but with these changes, it wouldn't occur anymore. Additionally, you questioned why the vertices array is used in the first place, since, from your understanding, these vertices are only used once.

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	viewer.drawCircles(circles.begin(), circles.end(), [](auto& c, auto& pos, auto& radius, auto& color)
	{
	pos = c.first;
	radius = c.second;
	color = {0.0, 1.0, 0.0, 1.0};
	return true;
	});

	std::vector<glm::vec2> vertices(mRender.circleVertices);
	for(unsigned int i = 0; i <= mRender.circleVertices; i++)
	{
	vertices[i] =
	{
	radius * glm::cos(2.0glm::pi<float>() static_cast<float>(i) / mRender.circleVertices),
	radius * glm::sin(2.0glm::pi<float>() static_cast<float>(i) / mRender.circleVertices)
	};
	}