Contents
How to pass a Bezier curve to the shader?
The Bezier curve is represented by two endpoints and two control points. Therefore, in order to pass to the shader a Bezier curve (or a set of the curves), we have to provide all the control points.
How are cubic Bezier curves rendered on GPU?
Our algorithm for rendering cubic spline curves is similar in spirit to the one for rendering quadratic curves. An oriented closed path is defined by cubic Bézier curve segments, each consisting of four control points. See Figure 25-3a. We assume the right-hand side of the curve to be considered inside.
What does a positive result mean for a convex curve?
For convex curves, a positive result means the pixel is outside the curve; otherwise it is inside. For concave curves, this test is reversed. At the end of the article an example implementation of that algorithm is provided (reproduced below).
How is color interpolated in a Bezier line?
A few words on the color interpolation. For that part the main idea is to define to which of the three Bezier fragment the current point belongs to, and then interpolate between the two colors of endpoints of that Bezier segment based on the location of the point to the endpoints of the segment. Refer to the source code for concrete example.
Can you draw two geometries with GLSL shaders?
This code demonstrates how a GLSL shaders can help to solve the above problems. It is possible to draw two types of geometries with the provided shaders: Both of the geometries can be placed in a 3D space with any line thickness.
Is there a GLSL function to draw a Bezier line?
Hi! i thought i could leave my 2c 🙂 It’s about the bezier function. There’s a built-in GLSL function that could help speed up the process. It is an interpolation function, mix ( vec4 A, vec4 B, float t ) that returns A + t (B – A).
How to draw a Bezier line given four control points?
For that part the main idea is to define to which of the three Bezier fragment the current point belongs to, and then interpolate between the two colors of endpoints of that Bezier segment based on the location of the point to the endpoints of the segment. Refer to the source code for concrete example. We were unable to load Disqus.