![]() Īnother solution is to move that seam to somewhere where its way less obvious. The “correct” solution to this is to calculate the mipmap level yourself and then pass it to tex2Dlod, but because thats too much for this tutorial, I’m just going to link this other excellent article to you on that. Thats because there the coordinates jump from -1.5 to 1.5, they still sample the same point in a repeating texture, but tex2D uses partial derivatives internally which then in those pixels conclude that we’re watching the texture from very far away, and choose a lower mipmap level. return the final color to be drawn on screen return col īut as you can see theres sometimes a weird seam opposite of “ 0 degree”. make input uvs centered and scaled to -1 to 1įixed4 col = tex2D(_MainTex, uv) * _Color As a small addition, I divided the angle by 2pi to make it go from -0.5 to 0.5, instead of -pi to pi, which is usually a more annoying number to work with. I put it in a function in a include file for reuse, but you can of course put the function in your shader file, or even do the calculations inline. So we use the the atan2 to calculate the angle and calculate the length of the position for the distance and store it in a float2 (I used that because its convenient, you can also build your own struct for that if you prefer that). While in cartesian 2d space the 2 variables we use are the “right-ness” as well as the “up-ness”(or “down-ness” depending on context), in polar coordinates the 2 variables are the angle around the center and the distance from that center. While you manipulate polar coordinates, remember that not all rules from geometry in cartesian coordinates apply, but I encourage you to play with all ideas you have and see what happens.Ĭonverting cartesian to polar coordinates □︎ Now I want to introduce you to polar coordinates, how to convert to and from them and show you how to use them. ![]() That pushing things to the right, pushes them to the right, up is up etc… This is called “cartesian coordinates”. There were multiple spaces of those like object, world, screen, uv space and maybe more but the base rules were always the same most of the time. Move point B and you will see that the perp is always the same with the x and y swapped and one negated.So far whenever we used coordinates we had a clear grid of 2 or 3 axes in which we could manipulate things and push them around. The perpendicular ( aka normal )can be found by simply swapping the x and y values and negating one of the two -> ĭepending on which on you negate gives you the directing your vector goes into.Įdit: Geogebra can easily visualize this. Note: if two vectors are parallel the resulting vector will be. Provided that both vectors are normalized. ![]() The c vector is your perpendicular vector to the plane. Shift the x component to the bottom, multiply each component with their diagonal and subtract The cross product can be calculated very quick by applying the following trick: If GLM doesn't have the cross product function you can simply do it manually: Your fingers represent the vectors, that's your plane. Visualize this by making a right angle between your thumb and index finger. To get the perpendicular of a plane you simply need 2 vectors and take the cross product of the two. So the question was for 3D and It isn't very clear whether you're drawing 2 vectors or 3. Apply it to the point in space we are rotating around To_return = glm::rotate(to_return, angle* RAD_TO_DEG, normal) ![]() Glm::vec3 to_return = glm::normalize(glm::cross(normal,to_cross)) Make sure that the normal and cross vector are not the same, if they are change the cross vector Create a vector that will be used for the dot product Normalize the normal (axis to rotate on) Solution Code glm::vec3 CreateAngledPoint(glm::vec3 rotation_point, float radius, float angle, glm::vec3 normal) The reason for this is so I can loop through and create a point cloud in 3D space and then join them together to make shapes such as cylinders (see photo) The function's purpose is to pass a direction vector into a function, radius, and an angle and it will create a point around the origin at x angle in space. Here is a basic visualization of what I need. ![]() I would like to keep the solution compatible with GLM as I wish to have everything standardized. I have been using GLM and have tried using its built in vector rotation functions but to no avail. I understand that in 3D there is an infinite amount of vectors that could be produced from this calculation, but I only require 1. I need a function that can take a vector as an input and provide a vector that is at a 90-degree angle to the provided vector. ![]()
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