canysway dev blog

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...

The simple image is made like this. void  mainImage(  out   vec4  fragColor,  in   vec2  fragCoord ){      // Normalized pixel coordinates (from 0 to 1)      vec2  uv = fragCoord/iResolution.xy;           //uv.x = uv.x - 0.3;      fragColor =  texture (iChannel0, uv); } I think GPU processing has two major steps. Normalizing and Pointing. 1. Normalizing Each pixel has screen coordinate and we need to normalizing from 0.0 to 1.0, because there are many displays with various resolutions around us. We can not manage it at each resolution. It is very troublesome. So we should normalize it :   vec2   uv = fragCoord/iResolution.xy; 2. Pointing I told you each pixel has a screen coordinate. At each coordinate we need to link with sampler's coordinate. Sampler has also coordinate 0.0 to 1.0. As a result, we see the samplers p...