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c++openglpolygonsfmltexture-mapping

How do I map a texture correctly onto a convex polygon in SFML or OpenGL?

I want to represent my Objects as textured convex Polygons. For the most part those will just be rotated rectangles but i want to support convex shapes too and thats where the problems arise.

I worked with Blender a while ago and there you could unwrap the 3D-Objects and explicetely tell Blender which vertex of the Shape has which Position on the Texture.

Would it maybe be better to just request the Texture to have the size of the bounding Rectangle of the Shape so I can just apply the texture with SFML?

PS: Im sorry i cant post pictures to clarify my question.

Solution

  • or OpenGL

    In OpenGL, typically you'll have two (or more!) vertex attributes: position and texture coordinate. That's basically saying which vertex of the Shape has which Position on the Texture.

    That's what SFML has to be doing internally, and since its Open-Source, you might just peek inside and see if your "bounding rectangle" idea has a chance of working (my guess is that it indeed does).