Lighthouse Zoom In

WebGL Shader

This page includes the GLSL shader source code to zoom in. The example zooms into a photograph of a lighthouse.

Shader Effect WebGL Animation Shader Effect Zoom In

Vertex Shader

 
attribute vec4 a_position;   
attribute vec2 a_tex_coord0;
varying vec2 v_tex_coord0;

uniform float uf_time;          
uniform mat4 um4_matrix;
uniform mat4 um4_pmatrix;
           
void main(void) {

 vec2 tex_coord = a_tex_coord0;
 
 // Adjust the amount
 // of zoom per frame.
 float f_time = uf_time * 0.75;
 
 if (tex_coord.s == 1.0){
  tex_coord.s -= f_time;
 }
 else {
  tex_coord.s += f_time;
 }
 
 if (tex_coord.t == 1.0){
  tex_coord.t -= f_time;
 }
 else {
  tex_coord.t += f_time;
 } 

 gl_Position = um4_pmatrix * um4_matrix * a_position;
 v_tex_coord0 =  tex_coord; 
 
}

Fragment Shader

precision mediump float;
uniform sampler2D u_sampler0;
varying vec2 v_tex_coord0;

void main(void) {
 gl_FragColor = texture2D(u_sampler0, v_tex_coord0); 
}

Texture Map

Summary

This example applies WebGL shaders to zoom into a photograph of a lighthouse.

Simple Shaders: Learn WebGL Book 4

Simple Shaders explains how to prepare basic WebGL GLSL shaders. This new Kindle book includes detailed instruction and links to many interesting WebGL shader examples online. Learn to program WebGL shaders. Harness the power of the Graphics Processing Unit (GPU).

Simple Shaders: Learn WebGL Book 4