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uniform float alpha = 0.4;
flat in vec3 finalStateColor;
flat in vec3 finalBoneColor;
flat in mat4 sphereMatrix;
in vec3 viewPosition;
#ifdef GL_ARB_conservative_depth
/* Saves a lot of overdraw! */
layout(depth_greater) out float gl_FragDepth;
#endif
layout(location = 0) out vec4 fragColor;
layout(location = 1) out vec4 lineOutput;
#define cameraPos ViewMatrixInverse[3].xyz
float get_depth_from_view_z(float z)
{
if (ProjectionMatrix[3][3] == 0.0) {
z = (-ProjectionMatrix[3][2] / z) - ProjectionMatrix[2][2];
}
else {
z = z * ProjectionMatrix[2][2] / (1.0 - ProjectionMatrix[3][2]);
}
return z * 0.5 + 0.5;
}
void main()
{
const float sphere_radius = 0.05;
bool is_perp = (ProjectionMatrix[3][3] == 0.0);
vec3 ray_ori_view = (is_perp) ? vec3(0.0) : viewPosition.xyz;
vec3 ray_dir_view = (is_perp) ? viewPosition : vec3(0.0, 0.0, -1.0);
/* Single matrix mul without branch. */
vec4 mul_vec = (is_perp) ? vec4(ray_dir_view, 0.0) : vec4(ray_ori_view, 1.0);
vec3 mul_res = (sphereMatrix * mul_vec).xyz;
/* Reminder :
* sphereMatrix[3] is the view space origin in sphere space (sph_ori -> view_ori).
* sphereMatrix[2] is the view space Z axis in sphere space. */
/* convert to sphere local space */
vec3 ray_ori = (is_perp) ? sphereMatrix[3].xyz : mul_res;
vec3 ray_dir = (is_perp) ? mul_res : -sphereMatrix[2].xyz;
float ray_len = length(ray_dir);
ray_dir /= ray_len;
/* Line to sphere intersect */
const float sphere_radius_sqr = sphere_radius * sphere_radius;
float b = dot(ray_ori, ray_dir);
float c = dot(ray_ori, ray_ori) - sphere_radius_sqr;
float h = b * b - c;
float t = -sqrt(max(0.0, h)) - b;
/* Compute dot product for lighting */
vec3 p = ray_dir * t + ray_ori; /* Point on sphere */
vec3 n = normalize(p); /* Normal is just the point in sphere space, normalized. */
vec3 l = normalize(sphereMatrix[2].xyz); /* Just the view Z axis in the sphere space. */
/* Smooth lighting factor. */
const float s = 0.2; /* [0.0-0.5] range */
float fac = clamp((dot(n, l) * (1.0 - s)) + s, 0.0, 1.0);
fragColor.rgb = mix(finalStateColor, finalBoneColor, fac * fac);
/* 2x2 dither pattern to smooth the lighting. */
float dither = (0.5 + dot(vec2(ivec2(gl_FragCoord.xy) & ivec2(1)), vec2(1.0, 2.0))) * 0.25;
dither *= (1.0 / 255.0); /* Assume 8bit per color buffer. */
fragColor = vec4(fragColor.rgb + dither, alpha);
lineOutput = vec4(0.0);
t /= ray_len;
gl_FragDepth = get_depth_from_view_z(ray_dir_view.z * t + ray_ori_view.z);
}
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