40 lines
1.5 KiB
Text
40 lines
1.5 KiB
Text
shader_type spatial;
|
||
render_mode unshaded, depth_draw_never, cull_disabled;
|
||
|
||
// Uniforms that define the bounding box in world space.
|
||
uniform vec3 bbox_min;
|
||
uniform vec3 bbox_max;
|
||
|
||
void vertex() {
|
||
// Compute the particle’s center in world space.
|
||
// (This assumes that your particle’s mesh is centered at the local origin.)
|
||
vec3 particle_center = (MODEL_MATRIX * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
|
||
|
||
// Check if the particle’s center is within the provided bounding box.
|
||
bool inside = (particle_center.x >= bbox_min.x && particle_center.x <= bbox_max.x &&
|
||
particle_center.y >= bbox_min.y && particle_center.y <= bbox_max.y &&
|
||
particle_center.z >= bbox_min.z && particle_center.z <= bbox_max.z);
|
||
|
||
if (inside) {
|
||
// If the particle qualifies, we override its vertex positions so that
|
||
// regardless of its original quad, it covers the full clip space (i.e. the whole screen).
|
||
// This assumes exactly 4 vertices per instance.
|
||
if (VERTEX_ID == 0) {
|
||
POSITION = vec4(-1.0, -1.0, 0.0, 1.0);
|
||
} else if (VERTEX_ID == 1) {
|
||
POSITION = vec4( 1.0, -1.0, 0.0, 1.0);
|
||
} else if (VERTEX_ID == 2) {
|
||
POSITION = vec4(-1.0, 1.0, 0.0, 1.0);
|
||
} else {
|
||
POSITION = vec4( 1.0, 1.0, 0.0, 1.0);
|
||
}
|
||
} else {
|
||
// Otherwise, move the geometry far off clip space so it isn’t rendered.
|
||
POSITION = vec4(2.0, 2.0, 2.0, 1.0);
|
||
}
|
||
}
|
||
|
||
void fragment() {
|
||
// Output pure red color.
|
||
ALBEDO = vec3(1.0, 0.0, 0.0);
|
||
}
|