varying mediump vec2 qt_TexCoord0; | |
uniform lowp sampler2D gradientSource; | |
uniform highp float qt_Opacity; | |
uniform highp float startAngle; | |
uniform highp vec2 center; | |
void main() { | |
const highp float PI = 3.14159265; | |
const highp float PIx2inv = 0.1591549; | |
highp float a = (atan((center.y - qt_TexCoord0.t), (center.x - qt_TexCoord0.s)) + PI - startAngle) * PIx2inv; | |
gl_FragColor = texture2D(gradientSource, vec2(0.0, fract(a))) * qt_Opacity; | |
} |