Skip to main content

OpenGL SL - Select compiler (Shader Toy)

GLSL (OpenGL Shading Language) is a language that enables developers to directly control the graphics pipeline. We will do GPU programming using GLSL. And I recommend the Shadertoy to easily program it. By using Shadertoy, you can see the results of GLSL programming on the screen without OpenGL. It looks like below.

comfortable glsl compiler : shadertoy


I made simple mosaic effect. The great thing of this is you can program and take result on the screen in real time. We do not need to write GL code directly :)

But this tool also has some rules.
Because we don't program GL, there are some promised uniform variables. And I'll introduce some important input uniforms.


uniform vec3 iResolution   (x,y,z of your screen resolution)
uniform float iTime            (current time second info)
uniform float iFrame             (current frame number info)
uniform vec4 iMouse                 (mouse click position)
uniform samplerXX iChanneli     (sampler image, video of iChannel0 ~ iChannel4)


If you want to see more rules, please go to Shadertoy site.

Labels:

Comments

Post a Comment

Popular posts from this blog

OpenGL SL - Translate, roate, and scale

Translate, rotate and scale are most basic element of image effect. If you didn't understand how make effect at each pixel, please read again before post "Show Video and Image" . 1. Translate Translation means each pixel move parallel on the x, y-axis. In other words, if you want to translate 0.25 on the x-axis, a pixel should point to a distance of -0.25 from the original. Translate ex) void mainImage( out vec4 fragColor, in vec2 fragCoord ){     vec2 uv = fragCoord/iResolution.xy;     if (uv.x < 0.5 ){         // translate to x ( -0.25 )         uv.x += 0.25 ;     } else {         // translate to x ( +0.25 )         uv.x -= 0.25 ;     }     fragColor = texture (iChannel0, uv); } result) 2. Scale Scale also has a  similar concept to parallel translation. If you want to zoom in twice, each pixel s...
Post a Comment
Read more

OpenGL SL - Mosaic effect

Mosaic effect is similar to lowering the resolution of an image. Let's see example image. And full source code likes below. void mainImage( out vec4 fragColor, in vec2 fragCoord ){     // Normalized pixel coordinates (from 0 to 1)     vec2 uv = fragCoord/iResolution.xy;     if (uv.x > 0.7 && uv.y < 0.4 ){          //left bottoom small image         uv.x -= 0.6 ;         uv *= 2.0 ;         fragColor = texture (iChannel0, uv);         fragColor += vec4 ( 0.2 );         return ;     }     //mosaic effect     uv = uv * 30.0 ;     vec2 uv = floor (uv);     uv = uv/ 30.0 ;     fragColor = texture (iChannel0, uv); } The key function of mosaic effect is "floor" If you want to make it sharper, multiply uv by ...
Post a Comment
Read more

OpenCV : How to setting OpenCV in CLion

CLion is A Cross-Platform IDE for C and C++ by JetBrains Setting OpenCV in CLion is so easy. FIrst, make new c++ project. Second, edit CmakeList.txt cmake_minimum_required( VERSION 3.10 ) project( [YourProject] ) set( CMAKE_CXX_STANDARD 11 ) find_package( OpenCV REQUIRED ) add_executable( [YourProject] main.cpp ) target_link_libraries( [YourProject] ${OpenCV_LIBS} ) At Last include OpenCV to main.cpp #include <iostream> #include "opencv2/opencv.hpp" using namespace std ; using namespace cv ; ...
Post a Comment
Read more