#version 100 | |
precision mediump float; | |
uniform vec4 urect_Stage0; | |
uniform float uRTHeight; | |
uniform vec4 urect_Stage1; | |
uniform vec4 uinnerRect_Stage2; | |
uniform vec2 uinvRadiiXY_Stage2; | |
varying vec4 vColor; | |
void main() | |
{ | |
vec4 fragCoordYDown = vec4(gl_FragCoord.x, uRTHeight - gl_FragCoord.y, 1.0, 1.0); | |
vec4 output_Stage0; | |
{ | |
// Stage 0: AARect | |
float xSub, ySub; | |
xSub = min(fragCoordYDown.x - urect_Stage0.x, 0.0); | |
xSub += min(urect_Stage0.z - fragCoordYDown.x, 0.0); | |
ySub = min(fragCoordYDown.y - urect_Stage0.y, 0.0); | |
ySub += min(urect_Stage0.w - fragCoordYDown.y, 0.0); | |
float alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0)); | |
alpha = 1.0 - alpha; | |
output_Stage0 = (vColor * alpha); | |
} | |
vec4 output_Stage1; | |
{ | |
// Stage 1: AARect | |
float xSub, ySub; | |
xSub = min(fragCoordYDown.x - urect_Stage1.x, 0.0); | |
xSub += min(urect_Stage1.z - fragCoordYDown.x, 0.0); | |
ySub = min(fragCoordYDown.y - urect_Stage1.y, 0.0); | |
ySub += min(urect_Stage1.w - fragCoordYDown.y, 0.0); | |
float alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0)); | |
output_Stage1 = (output_Stage0 * alpha); | |
} | |
vec4 output_Stage2; | |
{ | |
// Stage 2: EllipticalRRect | |
vec2 dxy0 = uinnerRect_Stage2.xy - fragCoordYDown.xy; | |
vec2 dxy1 = fragCoordYDown.xy - uinnerRect_Stage2.zw; | |
vec2 dxy = max(max(dxy0, dxy1), 0.0); | |
vec2 Z = dxy * uinvRadiiXY_Stage2; | |
float implicit = dot(Z, dxy) - 1.0; | |
float grad_dot = 4.0 * dot(Z, Z); | |
grad_dot = max(grad_dot, 1.0e-4); | |
float approx_dist = implicit * inversesqrt(grad_dot); | |
float alpha = clamp(0.5 - approx_dist, 0.0, 1.0); | |
output_Stage2 = (output_Stage1 * alpha); | |
} | |
gl_FragColor = output_Stage2; | |
} |