CSE380/hw3/dist/hw3_assets/shaders/gradient_circle.fshader

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2022-05-23 06:00:37 -04:00
precision mediump float;
varying vec4 v_Position;
uniform vec4 circle_Color;
void main(){
// Default alpha is 0
float alpha = 0.0;
// Radius is 0.5, since the diameter of our quad is 1
float radius = 0.5;
// Get the distance squared of from (0, 0)
float dist_sq = v_Position.x*v_Position.x + v_Position.y*v_Position.y;
if(dist_sq < radius*radius){
// Multiply by 4, since distance squared is at most 0.25
alpha = 4.0*dist_sq;
}
// Use the alpha value in our color
gl_FragColor = vec4(circle_Color);
gl_FragColor.a = alpha;
}