Code works more or less good

src/SparkEmitter.h

@@ -50,6 +50,10 @@ namespace ZL {
 
 		std::string shaderProgramName;
 
+		// Sparks spawn within this radius of each emission point. 0 means
+		// "spawn exactly at the point" (legacy behavior).
+		float emissionRadius;
+
 		bool configured;
 		// Rebuilds the CPU-side quad/UV arrays. If cameraViewMatrix is identity,
 		// particles are rendered as axis-aligned quads in world XY and sorted by
@@ -90,6 +94,9 @@ namespace ZL {
 		void setScaleRange(float minVal, float maxVal) { scaleRange.min = minVal; scaleRange.max = maxVal; }
 		void setLifeTimeRange(float minVal, float maxVal) { lifeTimeRange.min = minVal; lifeTimeRange.max = maxVal; }
 		void setEmissionDirection(const Vector3f& dir) { emissionDirection = dir; }
+		// 0 = spawn exactly at the emission point; >0 = spawn at a uniform random
+		// point inside a 3D ball of this radius around the emission point.
+		void setEmissionRadius(float r) { emissionRadius = r; }
 		void markConfigured() { configured = true; }
 		bool isConfigured() const { return configured; }