Basic Gradient Effects

Learn how to create linear and radial gradient effects using GLSL

Overview

• Implement a vertical gradient using UV as the factor.

Learning Objectives

• Understand the principles of linear gradients
• Learn the mathematical foundations of radial gradients
• Master color blending techniques in GLSL

Inputs

• vec2 u_resolution — Canvas size in pixels.
• float u_time — Time in seconds.

Key Concepts

• Normalize pixel coordinates to UV.

vec2 uv = gl_FragCoord.xy / u_resolution.xy;

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

float t = uv.y;
vec3 color = vec3(t);

• Keep the factor inside [0,1].

t = clamp(t, 0.0, 1.0);

How To Implement (Step-by-step)

• Normalize coordinates: uv = gl_FragCoord.xy / u_resolution.xy.
• Set factor: t = uv.y.
• 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

• Don’t use raw pixels without normalization.