Qt Quick 3D - Scene Effects Example
#version 450 layout(location = 0) in vec2 qt_TexCoord0; layout(location = 0) out vec4 fragColor; layout(std140, binding = 0) uniform buf { mat4 qt_Matrix; float qt_Opacity; float value; }; vec3 hsv2rgb(vec3 c) { vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0); vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www); return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y); } #define TWO_PI 6.28318530718 void main() { vec2 st = qt_TexCoord0; vec4 color = vec4(1.0); // Use polar coordinates instead of cartesian vec2 toCenter = vec2(0.5)-st; float angle = atan(toCenter.y,toCenter.x); float radius = length(toCenter)*2.0; if (radius <= 1.0) { color.rgb = hsv2rgb(vec3((angle/TWO_PI)+0.5,radius,value)); } else { discard; } fragColor = color * qt_Opacity; }