![]() HSB was originally designed to be represented in polar coordinates (based on the angle and radius) instead of cartesian coordinates (based on x and y). This spatial distribution of color can be very handy it's more intuitive to pick a color with HSB than with RGB. Take a moment to read the rgb2hsv() and hsv2rgb() functions in the following code.īy mapping the position on the x axis to the Hue and the position on the y axis to the Brightness, we obtain a nice spectrum of visible colors. HSB stands for Hue, Saturation and Brightness (or Value) and is a more intuitive and useful organization of colors. As you probably know there are different ways to organize color besides by red, green and blue channels. We can't talk about color without speaking about color space. Use the step() function to create a colorful flag.Try the following exercises:Ĭompose a gradient that resembles a William Turner sunsetĪnimate a transition between a sunrise and sunset using u_time.Ĭan you make a rainbow using what we have learned so far? Play with them! It's time for you to explore and show off your skills from the previous chapter and make interesting gradients. You probably recognize the three shaping functions we are using on lines 25 to 27. Remember that the lines visualize the amount of colorA and colorB to mix per channel. Now, uncomment line number 25 and watch what happens. Right now all the channels go along the same line. Like the examples in the previous chapter, we are hooking the transition to the normalized x coordinate and visualizing it with a line. By doing that we gain control over the mixing percentages of each individual color channel, r, g and b. Instead of a single float, we can pass a variable type that matches the two first arguments, in our case a vec3. Robert Penner developed a series of popular shaping functions for computer animation known as easing functions, you can use this example as research and inspiration but the best result will come from making your own transitions. Then animate the transition using shaping functions. Change the beginning and ending color of the above code to match those emotions. What color seems most representative of it? How does it appear? How does it fade away? Think of another emotion and the matching color for it. Make an expressive transition between colors.Can you guess what the percentage range is? Yes, values between 0.0 and 1.0! Which is perfect for you, after those long hours practicing your karate moves with the fence - it is time to use them!Ĭheck the following code at line 18 and see how we are using the absolute values of a sin wave over time to mix colorA and colorB. ![]() In GLSL there is a very useful function, mix(), that lets you mix two values in percentages. Now that you know how colors are defined, it's time to integrate this with our previous knowledge. Green.rgb = yellow.bgb // Assign the blue channel of Yellow (0) to red and blue channels Mixing color Magenta = yellow.rbg // Assign the channels with green and blue swapped This flexibility embedded in shading language is a door for you to start thinking interchangeably about color and space coordinates.Īnother great feature of vector types in GLSL is that the properties can be combined in any order you want, which makes it easy to cast and mix values. These different ways of pointing to the variables inside a vector are just nomenclatures designed to help you write clear code. The following lines show all the ways to access the same data: vec4 vector p are usually used for spatial coordinates of a texture, which we'll see in a later chapter.) You can also access the data in a vector by using the index position,, and. vec3 red = vec3(1.0,0.0,0.0) ĭefining color using an x, y and z notation can be confusing and misleading, right? That's why there are other ways to access this same information, but with different names. If you are familiar with object oriented programming paradigms you've probably noticed that we have been accessing the data inside the vectors like any regular C-like struct. Before going further it's important to learn more about these variables and the subject of colors is a great way to find out more about them. We haven't much of a chance to talk about GLSL vector types.
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