Rectangle Color Split

Divide the screen area into two colors (left and right) using an if condition, mastering fragment judgment logic.

Overview

• Implement a horizontal gradient using UV as the factor.

Learning Objectives

• Understand how to use if conditional statements in GLSL.
• Learn to divide the screen based on the x-value of UV coordinates.
• Master the method of assigning different colors to different regions.

Prerequisites

• uv-coordinates
• solid-color

Key Concepts

• A horizontal gradient uses a 0-1 factor (usually UV) to blend colors.

float t = vUv.x;
vec3 color = vec3(t);

• Keep the factor inside [0,1].

t = clamp(t, 0.0, 1.0);

How To Implement (Step-by-step)

• Set factor: t = vUv.x.
• Map t to a color (grayscale or mix).
• Output gl_FragColor with alpha=1.

Self-check

• Does it compile without errors?
• Does the output match the goal?
• Are key values kept in [0,1]?

Common Mistakes

• If output is black, check your mask/factor isn’t always 0.