A bit of a shader beginner here. I’m trying to create an effect that basically warps part of a texture like this, based on where the mouse is:
Which I have working pretty well. But, I want it to be able to rotate and warp in any direction (depending on the angle from the mouse to the center of the canvas). I’ve tried rotating the resulting y offset with something like vec2(0., offsetY) * a 2d rotation matrix, and adding the result to the texture coordinates, but doing that ends up with some weirdness like:
Here’s my shadertoy link and the shader code: Shader - Shadertoy BETA
float sinc(float x, float amp, float freq) {
x = freq*x;
return amp*sin(x)/(x);
}
vec2 centeredCoord(vec2 c1, vec2 c2) {
return vec2(c1 / c2) * 2. - 1.; // between -1 and 1
}
mat2 rotate2D(float angle) {
return mat2(cos(angle), -sin(angle),
sin(angle), cos(angle));
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
// Declare variables
float PI = 3.14159;
float amplitude;
float ampFactor = .1;
float speedFactor = .3;
float AOIFactor = 2.;
float frequency = 50.;
float oscillations = 2.;
// How much deformation to do for this fragment
amplitude = sin(PI * iTime * speedFactor) * (PI - fract(iTime / oscillations * speedFactor) * PI) * ampFactor;
// Initialize texture coordinates
vec2 texCoord = centeredCoord(fragCoord.xy, iResolution.xx);
vec2 mouseCoord = centeredCoord(iMouse.xy, iResolution.xx);
// The main sinc functions
//float offsetX = sinc(texCoord.y - mouseCoord.y, amplitude, frequency);
float offsetY = sinc(texCoord.x - mouseCoord.x, amplitude, frequency);
// Rotate the result of the sinc functions...
vec2 tempCoord = vec2(0., offsetY);
vec2 rotatedCoord = tempCoord * rotate2D(PI * 1.);
//THIS produces undesirable results...
rotatedCoord = tempCoord * rotate2D(PI * 1.3);
// Apply rotation to the texture
vec2 newCoord = texCoord + rotatedCoord;
// Get distance from mouse
float dist = distance(mouseCoord, texCoord);
// Draw fragment
fragColor = texture(iChannel0, mix(newCoord, texCoord, clamp(0., dist * AOIFactor, 1.)));
}
If anyone knows what I’m doing wrong or can point me in the right direction, that would be great! Thanks!
