33 lines
1.0 KiB
Plaintext
33 lines
1.0 KiB
Plaintext
|
precision mediump float;
|
||
|
|
|
||
|
|
varying vec4 v_Position;
|
||
|
|
|
||
|
|
uniform vec4 circle_Color;
|
||
|
|
uniform vec4 default_Color;
|
||
|
|
|
||
|
|
// HOMEWORK 3
|
||
|
|
/*
|
||
|
|
The fragment shader is where pixel colors are decided.
|
||
|
|
You'll have to modify this code to make the circle vary between 2 colors.
|
||
|
|
Currently this will render the exact same thing as the gradient_circle shaders
|
||
|
|
*/
|
||
|
|
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;
|
||
|
|
float ratio = (1.0-(v_Position.x+0.25+v_Position.y+0.25));
|
||
|
|
|
||
|
|
// 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 = 1.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Use the alpha value in our color
|
||
|
|
gl_FragColor = vec4(default_Color[0]*ratio+circle_Color[0]*(1.0-ratio), default_Color[1]*ratio+circle_Color[1]*(1.0-ratio), default_Color[2]*ratio+circle_Color[2]*(1.0-ratio), default_Color[3]*ratio+circle_Color[3]*(1.0-ratio));
|
||
|
|
gl_FragColor.a = alpha;
|
||
|
|
}
|